No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Medical Applications of Cellulose and its Derivatives: Present and Future
Abstract
Cellulose is a naturally occurring material found in wood, cotton, hemp, and other plant-based materials, and consists of repeating anhydroglucose units joined by β-(1,4) linkages forming the basic repeating unit. It was first isolated from wood in 1885 by Charles F. Cross and Edward Bevan at the Jodrell Laboratory of the Royal Botanic Gardens, Kew, London. Cellulose is well known as one of the most abundant biodegradable materials in nature and has been widely used in medical applications such as wound dressing, tissue engineering, controllable drug delivery system, blood purification, etc., due to its biocompatibility, hydrophilicity, biodegradable, nontoxicity and antimicrobial properties. Although the primary use of cellulose films has been for wrapping purposes, it has also found an application in the treatment of renal failure, as well as in a variety of more recent and evolving clinical applications such as for scaffolds in tissue engineering, temporary skin substitute, haemostatic agent, post-operative adhesion barrier, and as a culture material for hepatocytes. Recently, there has been a decline in the use of many of the clinical applications of cellulose such as film and tubes manufactured from cellulose, which have historically been used for the treatment of renal failure, dialysis, etc., and new applications for its use are emerging. Among those that appear to be most promising is the use of microbial cellulose synthesized by Acetobacter xylinum, which shows vast potential as a novel wound healing system and scaffold for tissue regeneration. In this chapter, the use of cellulose in medical applications is reviewed and discussed.
... The growing demand for environmental sustainability has encouraged much of research into naturally occurring biodegradable materials. Cellulose is well known as one of the most abundant biodegradable materials in nature [1][2]. Cellulose is the main constituent of organic compound on earth, especially within wood fibers (e.g., kenaf, palm, cotton, hemp, flax, etc.) [3]. ...
... Cellulose was first discovered in 1838 by the French chemist Anselme Payen, who isolated it from plant matter and determined its chemical formula [2]. Cellulose consists of a linear chain of several hundred to many thousands of β(1 ! ...
... Based on those excellent properties, CNFs are potential in applications such as energy storage, sensing devices, water treatment, and air filtration. However, it still suffers from some drawbacks which are needed to be improved: (1) In order to obtain a better compatibility with matrices, it is worthwhile to note that more surface functionalization methods are greatly needed to be developed (2). Several processes could be a b c used to extract highly purified nanofibers from cellulosic materials that include physical, chemical, biological, and electrospinning methods. ...
Cellulose fibers which consist of a bundle of stretched cellulose chain molecules with cellulose fibril are the smallest structural unit of plant fiber. These elementary fibrils or nanofibers are about 2–20 nm in diameter and a few micrometers in length. Cellulose nanofiber (CNF) is the world’s most advanced bio-nanomaterial. As the cellulose is the most abundant, renewable, and sustainable biopolymer on earth, it creates low environmental impact in its production and disposal. In this chapter, the unique properties of CNFs were introduced including stiffness, biodegradability, biocompatibility, and ability to form a strong entangled nanoporous network, thermal properties, and swelling in water and water absorptivity. Different fabrication techniques including physical methods (e.g., mechanical refining), chemical methods (treatment with acids and alkalis), and biological methods (treatment with specific bacteria and enzymes) were discussed. The chemical grafting on the CNFs and deposition of nanoparticles on nanofiber surface were described. Finally, the future prospects and challenges of CNFs were presented.
... Regarding the size of the pores, they are too small for applications such as bone The average pore size was determined after around 25 meas-urements on 4 images per sample. Pores whose walls were broken by the cutting section method were not taken into account Cellulose repair, for which pores around 200 µm are required to allow osteoblasts to penetrate the network (Abbasi et al. 2020;Sindhu et al. 2014). To overcome this issue, it could be possible to shape grids by 3D printing with an adequate porosity. ...
... Depending on the material targeted application, specific DM and concentration can be selected to achieve suitable microstructure and mechanical properties. As an example, hydrogels are generally mechanically brittle for bone repair applications (Bai et al. 2018;Sindhu et al. 2014). It is shown here that it is possible to increase the viscoelasticity of hydrogels without increasing the amount of water in the hydrogel, as in the case of the B4 sample. ...
Carboxymethylcellulose (CMC) was functionalized using methacrylic anhydride (MA) to produce photo-crosslinkable methacrylated carboxymethylcellulose (mCMC). Optimization of the synthesis led to a wide range of mCMC samples with well-controlled degrees of methacrylation up to 76 ± 6%, surpassing the literature data. Aqueous mCMC formulations with different DM and concentrations of mCMC were UV-cured to obtain hydrogels, which were transformed into cryogels after freeze-drying. An innovative 13C CP-MAS solid-state NMR methodology was used to calculate the crosslinked methacrylate density in cryogels and thus in hydrogels. These values (from 4.3 10–3 to 1.3 10–2 mmol/cm3) were correlated with both the DM and the mCMC concentration in formulations. These parameters were used to control the material microstructure and rheological properties. As a result, the swelling ratio of hydrated cryogels could be modulated for applications requiring high or low water absorption. Moreover, it was shown that the elastic moduli G’ of the hydrated cryogels were superior to those of the original hydrogels, over the entire frequency range (0.1–10 Hz).
... It is frequently utilized as a disintegrant, diluent, binder, and lubricant in conventional tablets and capsules (Builders and Arhewoh, 2016). Due to its biodegradability, biocompatibility, nontoxicity, hydrophilicity and antimicrobial properties, cellulose is utilized in wound dressing, controllable drug delivery system, tissue engineering, blood purification, and other applications (Sindhu ., 2014). ...
Among polysaccharides in algae, starch and cellulose, are the most
prevalent forms. These are called storage and structural polysaccharides,
respectively. In addition to these, the agar, alginates, and carrageenans are
also extracted from macroalgae. The bulk of commercial seaweed extracts
comes from these three hydrocolloids. The ulvans, fucoidans and laminarin
are the other important polysaccharides found in algae. The commercial
applications of algal polysaccharides in industries such as the food,
cosmetic, pharmaceutical, paper etc., are well known but the algal
polysaccharides as potential medicines are less discussed.
... The high natural biodegradability, biocompatibility, hydrophilicity, and nontoxicity of cellulose make it a significant material for desired medical applications, such as tissue engineering, blood purification, hemostatic agent, hepatocyte culture material, wound dressing, enzyme inhibitor, post-operative adhesion barrier, and controlled drug delivery system Dhital, Gidley, & Warren (2015); More, Antanitta. S, Khonde, & Kandasubramanian (2024); Sindhu, Prasanth, & Thakur (2014). Plants and bacteria (vascular plants, cotton, jute, corn, rice, Agrobacterium, Sarcina ventriculi, and genera Acetobacter) are the primary sources of cellulose, where the cell walls of plants possess cellulose to provide structural integrity Gorgieva & Trček (2019); Heinze, El Seoud, & Koschella (2018); Mohamad Amini (2024). ...
... Furthermore, the average pore size observed by SEM for the cryogels was 25.5 ± 8.8 µm (Fig. 3a, b). This average pore size was not suitable for developing materials targeting cell growth and tissue repair, that should display pores around 100-200 µm [36,45]. Consequently, the preparation of cryogels through DLP-printed hydrogel freeze-drying did not seem an appropriate process for creating porous materials for tissue engineering. ...
Two vat polymerization techniques were evaluated to print innovative hydrogel scaffolds for tissue engineering, from aqueous photo-crosslinkable formulations based on methacrylated carboxymethylcellulose (mCMC). A first formulation containing 2 wt% mCMC with a methacrylation degree (DM) of 34% and lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as photoinitiator was specifically developed for digital light processing (DLP). Considering their viscoelastic properties measured by shear rheology, the DLP-printed hydrogels were proposed for soft-tissue repair. Interestingly, the swelling ratio and shape of the printed hydrogels were found to be preserved when immersed in a physiological environment. While DLP-printed hydrogels demonstrated impressive X- and Y-resolutions (85 µm), they were limited in producing hollow objects in the Z-direction. To address this limitation, the 3D printing of complex mCMC hydrogels through two-photon polymerization (TPP) was investigated for the first time, using a second formulation composed of 4 wt% mCMC (DM = 50%). 3D scaffolds with cavities of 30 µm were successfully printed with a resolution of 10 µm, paving the way for the design of scaffolds with controlled and precise structures, for soft-tissue engineering.
Graphical abstract
... It is frequently utilized as a disintegrant, diluent, binder, and lubricant in conventional tablets and capsules (Builders and Arhewoh, 2016). Due to its biodegradability, biocompatibility, nontoxicity, hydrophilicity and antimicrobial properties, cellulose is utilized in wound dressing, controllable drug delivery system, tissue engineering, blood purification, and other applications (Sindhu et al., 2014). ...
The water world is the primary untapped source of naturally occurring
products with structurally distinct potential that are primarily found in
living things and are not competitive with land utilization or agriculture,
providing a source of income, food, medicine, numerous benefits to human health,
ecological benefits, ecosystem services, and employment. Marine algae are
important sources of chemical compounds that are beneficial for health and
have been extensively utilized for decades. In addition to being novel
nourishment with significant nutritional benefits, marine algae are
speculated to serve as the primary producers of some of the highly bioactive
substances found in marine resources. Algae, comprising seaweeds and
microalgae, contribute to the production of seaweeds used in aquaculture
around the world. Marine algae, one of the most significant potentially
known renewable resources in the ocean and existing in a diversity of
diverse environs and present in all prevailing bionetworks on Globe,
comprise an extremely essential element of the marine ecosystem
contributing a major feeding, breeding and nursery ground for marine
animals as well sunrise sector resources for human being.
... 43 • Cellulose is used in medical applications like tissue engineering, controlled DDS, wound dressing and blood purification. 44 • Pectin has been used as a binder, as a transporter of drugs in drug delivery as well as a controlled release matrix. 45 • Collagen dressings are currentlyused to treat burns, trauma, infectious and surgical skin injuries, and chronic wounds. ...
In this review wehave focused upon the various wound types, wound dressing stages, and wound dressing classification and characteristics. The main objective of this review is to explain the purpose of wound dressings and different types of wound dressings used. Further we have emphasized upon various biomaterials employed in dressings and their need in specific wound dressings. Biomaterials are used in the dressings to improve the healing rate of the injury, maintain moisture at the area of wound, heamostasis and reduce inflammation. So, to achieve this purpose, various approaches of wound dressings and the role of various biomaterials are also discussed. The properties, methods of preparation, advantages, and disadvantages along with future scope are discussed.
... 59 Cellulose is widely used in many TE applications, for example, controllable drug delivery systems, wound dressings, and blood purification owing to its properties such as hydrophilicity, antimicrobial, biocompatibility, nontoxicity, and biodegradability. 94 Moreover, cellulose and its blends have been used for the fabrication of many biomaterials such as hydrogels, nanoparticles, scaffolds, and films. In 2018, Basu et al. fabricated CMC-based films with the intention of healing wounds in diabetic and normal rats. ...
Wound healing is a complex and dynamic process that comprises of a series of molecular and cellular events that occur after tissue injury. The injuries of the maxillofacial and oral region caused by trauma or surgery result in undesirable wound healing such as delayed wound closure and formation of scar tissue. Skin tissue engineering/regeneration is an emerging approach towards faster, superior, and more effective resolution of clinically significant wounds effectively. A multitude of tissue engineering principles approaches are being put to action for the fabrication of hydrogels, electrospun sheets, 3D scaffolds, and thin films that can be used as wound dressings materials, sutures, or skin substitutes. Thin films are advantageous over other materials owing to their flexibility, ability to provide a barrier against external contamination, easy gaseous exchange and easy monitoring of wounds. This review focuses on wound-dressing films and their significance and discusses various fabrication techniques. Additionally, we explore various natural biopolymers that can be used for fabrication of skin tissue engineering materials.
... For example, cellulose is a relatively inert, mechanically strong, and biocompatible polymer [33][34][35]. It possesses a supramolecular 3D ultrafine highly porous fiber network that is suitable for drug dispersion, selectively permeable, and highly 2 of 12 water-absorbent [36]. Chitin [37], a biopolymer structurally similar to cellulose with an acetamide group on the C-2 atom, is an attractive material as a DDS matrix [38] due to its remarkable strength. ...
This mini-review focuses on the various roles that ionic liquids play in the development and applications of biopolymer-based drug delivery systems (DDSs). Biopolymers are particularly attractive as drug delivery matrices due to their biocompatibility, low immunogenicity, biodegradability, and strength, whereas ILs can assist the formation of drug delivery carriers as 1. dopants to control drug release rate; 2. anchoring agents to incorporate APIs into biopolymeric materials; 3. actives (in the form of API-ILs) for controlled release; or 4. a matrix preparation media.
... Due to its biocompatibility, hydrophilicity, biodegradability, and nontoxicity properties for cellulose, it is the most abundant biodegradable material and has been widely used in medical applications, such as wound dressing, tissue engineering, controllable drug delivery system, and blood purification [46]. The bacterial cellulose has better properties compared to plant cellulose, such as higher crystallinity (80−90%) [47], water absorption capacity [48], and a higher degree of polymerization (8000) [49]. ...
Bacterial cellulose (BC) or microbial cellulose (MC) was considered a bioactive material characterized by high absorbed water, high crystalline, high tensile strength, and biodegradability. However, bacterial cellulose has wide applications, such as biomedical, textile, paper industries, food, drug release, and cosmetic applications. So the microbial cellulose production from Acetobacter xylinum from different wastes such as carbon and nitrogen sources, for example, pineapple peel juice, sugar cane juice, dry olive mill residue, waste beer yeast, and wheat thin stillage, are characterized by FTIR, XRD, SEM, and TEM. The product yield of bacterial cellulose is affected by different factors such as the concentration of sugar in carbon source, temperature and time of incubator of the strain, and pH of media. So, it must be studied with the enzymatic pathway procedure.
... Vinegar has been used as a medicine since ancient times due to its healing effect on burns. The antibacterial properties of vinegar are mainly assumed to be responsible for the healing power of vinegar (Sindhu et al., 2014). Some studies have reported that oral administration of acetate has the effect of reducing muscle damages caused by physical exercises (Sugiyama et al., 2010). ...
Vinegar is a well-known natural food product derived from alcoholic and subsequently acetous fermentation of carbohydrate-rich foods. Vinegar is widely used in the food industry; domestically for pickling vegetables and fruits, and as an ingredient in condiments like salad dressings, ketchups, and mayonnaise; and traditionally as a food seasoning and preservative. Historically, vinegar has been used for medicinal purposes such as a cure for stomach aches, wounds, burns, rashes, and oedema conditions. Different types of vinegar are found worldwide such as rice, black, balsamic, grain, and fruit vinegars. These are produced from different raw materials, and using different fermentation methods to give unique tastes and flavours. Vinegar, while enhancing physiological functions such as lipid metabolism, blood glucose level control, and body weight management, also possesses anticancer, antibacterial, antioxidant, and anti-infection properties. It is considered as a good source material for many bioactive compounds including organic acids, melanoidins, polyphenols, ligustrazine, and tryptophol. The pharmacological and metabolic benefits of vinegar are believed to be due to these bioactive compounds present in vinegar. Acetic acid (CH3COOH) is the essential component of vinegar; it is slightly volatile and has a strong and sour aroma and flavour. Regular consumption of vinegar-containing foods is considered important for keeping many life-style related diseases like diabetes, hypertension, hyperlipidaemia, cancers, and obesity in check. Therefore, the present review aims at highlighting the health benefits associated with vinegar consumption for the physiological well-being of an individual.
... Vinegar has been used as a medicine since ancient times due to its healing effect on burns. The antibacterial properties of vinegar are mainly assumed to be responsible for the healing power of vinegar (Sindhu et al., 2014). Some studies have reported that oral administration of acetate has the effect of reducing muscle damages caused by physical exercises (Sugiyama et al., 2010). ...
Vinegar is a well-known natural food product derived from alcoholic and subsequently acetous fermentation of carbohydrate-rich foods. Vinegar is widely used in the food industry; domestically for pickling vegetables and fruits, and as an ingredient in condiments like salad dressings, ketchups, and mayonnaise; and traditionally as a food seasoning and preservative. Historically, vinegar has been used for medicinal purposes such as a cure for stomach aches, wounds, burns, rashes, and oedema conditions. Different types of vinegar are found worldwide such as rice, black, balsamic, grain, and fruit vinegars. These are produced from different raw materials, and using different fermentation methods to give unique tastes and flavours. Vinegar, while enhancing physiological functions such as lipid metabolism, blood glucose level control, and body weight management, also possesses anticancer, antibacterial, antioxidant, and anti-infection properties. It is considered as a good source material for many bioactive compounds including organic acids, melanoidins, polyphenols, ligustrazine, and tryptophol. The pharmacological and metabolic benefits of vinegar are believed to be due to these bioactive compounds present in vinegar. Acetic acid (CH3COOH) is the essential component of vinegar; it is slightly volatile and has a strong and sour aroma and flavour. Regular consumption of vinegar-containing foods is considered important for keeping many life-style related diseases like diabetes, hypertension, hyperlipidaemia, cancers, and obesity in check. Therefore, the present review aims at highlighting the health benefits associated with vinegar consumption for the physiological well-being of an individual.
... For a better future, energy devices having high power densities and current densities should be developed, and that is the current motto of entire energy storage organizations. In the upcoming years, energy storage devices will be the core of research and development and green synthesized energy materials including cellulose [4] are explored. Energy storage devices Overview such as batteries, supercapacitors, and energy conversional devices such as fuel cells are getting increasing attention. ...
The ever increasing proportion of an energy consuming society and the boost in industrialization accelerated the depletion of fossil fuel based energy sources at an alarming rate. This emphasizes the necessity of sustainable energy generation and storage to meet the daily energy demands. But, these alternative renewable energy sources like solar and wind power are intermittent and highly depend on weather, place and individuals. This creates the inevitability of suitable energy storage devices like batteries and supercapacitors. The interfacing of energy storing devices is required to maintain the supply chain equilibrium, power efficiency, regulate power fluctuations and reduce pollution. Besides, the boom in electric mobility and consumer electronics also require uninterrupted power supply. Hence, in the upcoming years the energy storing devices play a vital role in addressing the energy crisis. Innovations in new materials and technologies will be the core area of research and development in the coming future. 2D materials like graphene,transition metal carbides and nitrides (MXenes), transition metal borides (MBenes) and so on are the new class of materials among them MXenes are getting more attention in energy storage owing to its exceptional properties.
Graphical abstract:
... Synthetic polymer-based hydrogels are fabricated from poly ethylene glycol, poly acrylic acid, polyacrylamide, poly vinyl alcohol etc. [2][3][4][5]. Natural polymer-based hydrogels are derived from various natural polymers, such as cellulose, gelatin, peptides, chitosan and alginate, etc. [6][7][8] and can be employed as advanced materials for tissue and organ repair and regeneration [9][10][11]. ...
... The network structure of cellulose as mentioned earlier is the key factor for the use of cellulose in the sensor industry. Cellulose ( Fig. 1-chemical structure) having the chemical formula (C6H10O5)n consists of repeated units of the monomeric glucose [83]. Nano form of cellulose causes to possess great properties over bulk cellulose form in terms of extraordinary strength and large surface to volume ratio, larger surface area, which makes NC potential and efficient matrix material for sensor devices over the metal oxides and carbon materials. ...
Bio-based materials have been extensively studied by material scientists for their application in various fields of technologies. The interest in bio-based materials developed due to their ease of availability and structural properties suitable for various applications. Cellulose is the most abundant biopolymer derived from bio-based sources; further, its physical and chemical properties enhance the interest in cellulose and its further modifications for suitable applications. Cellulose and cellulose-based biopolymer composites are successfully implicated in sensor development and related technologies. The interest in the selection of cellulose and cellulose-based composites for sensor development developed due to its cost of production, physical and chemical properties, mouldability in different forms and morphologies. This book chapter primarily focuses on the extensive investigation of cellulose and cellulose-based composites for gas-sensing application, characterization and mechanism of recognition of various gases.
... Synthetic polymer-based hydrogels are fabricated from poly ethylene glycol, poly acrylic acid, polyacrylamide, poly vinyl alcohol etc. [2][3][4][5]. Natural polymer-based hydrogels are derived from various natural polymers, such as cellulose, gelatin, peptides, chitosan and alginate, etc. [6][7][8] and can be employed as advanced materials for tissue and organ repair and regeneration [9][10][11]. ...
The conversion of biomass waste products to valuable products like cellulose hydrogel films is important in cell regeneration. In this study, the various biomass wastes: thanaka heartwood (TH), sugarcane bagasse (SB) and rice straw (RS) were used as cellulose resources. They were chemically treated using acid and alkali to obtain cellulose fibers. The yield percent of cellulose fibers depends on the nature of biomass materials. Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analyses showed that the amount of lignin and hemicellulose from these samples were successfully reduced by chemical treatment. Cellulose fibers were treated using the dimethylacetamide/lithium chloride (DMAc/LiCl) system to obtain cellulose hydrogel solutions. Following this, the cellulose hydrogel films were prepared employing the phase inversion method without cross-linker. These films were transparent and flexible. In the present study, water retainable property and viscoelasticity of cellulose hydrogel films were measured. Antimicrobial activity tests of cellulose solutions have been carried out to be utilized to hydrogel films for biomedical application.
... Cellulose is a naturally occurring polymer used in biomedical applications for its biocompatibility, biodegradability, low-toxicity and good absorption properties [78,79]. There are different cellulose sources and derivatives. ...
Chronic wounds represent an economic burden to healthcare systems worldwide and a societal burden to patients, deeply impacting their quality of life. The incidence of recalcitrant wounds has been steadily increasing since the population more susceptible, the elderly and diabetic, are rapidly growing. Chronic wounds are characterised by a delayed wound healing process that takes longer to heal under standard of care than acute (i.e. healthy) wounds. Two of the most common problems associated with chronic wounds are inflammation and infection, with the latter usually exacerbating the former. With this in mind, researchers and wound care companies have developed and marketed a wide variety of wound dressings presenting different compositions but all aimed at promoting healing. This makes it harder for physicians to choose the correct therapy, especially given a lack of public quantitative data to support the manufacturers' claims. This review aims at giving a brief introduction to the clinical need for chronic wound dressings, focusing on inflammation and evaluating how bio-derived and synthetic dressings may control excess inflammation and promote healing.
... Cellulose and its derivatives have been used for medical applications-such as in renal dialysis, wound dressings, and anti-bacterial composites-for many years (Sindhu et al. 2014). The molecular self-assembly of structural oligosaccharides is one of the targets in the investigation of the effects of carbohydrate clusters on cellular responses, such as in hepatocellular carcinoma cells (Yoshiike and Kitaoka 2011;Kitaoka et al. 2013), myoblast cells and their alignment , human embryonic kidney 293 cells (HEK293) expressing toll-like receptor 2 (TLR2) (Hatakeyama et al. 2019a), and lectin-binding (Ogawa et al. 2012;Hatakeyama et al. 2019b) activities. ...
Native cellulose is mainly found in phytomass, such as trees and other plants. It has a regular hierarchical nanoarchitecture, in which the extended macromolecular chains are aligned and closely packed in parallel to form the crystalline nanofibrils of cell walls. In the context of material utilization, nanocellulose is a collective term for nano-ordered assemblies of cellulose chains. In recent times, it has been produced in large quantities from woody bioresources. In addition, nanocellulose has some fascinating physicochemical properties, such as high strength, light weight, transparency, birefringence, and low thermal expansion. These properties have enabled broad functional design of nanocellulose-based materials; but most of them are facing serious competition from various products that already exist. However, nanocellulose is not just a green alternative to existing materials. Rather, it is expected to make a profound difference in terms of pioneering novel functions. The present review focuses on the unexpected features of nanocellulose materials, triggered by details of the inherent nanoarchitecture of native cellulose.
... The biodegradable and biocompatible nature of cellulose along with its natural origin and availability resulted in its application as tissue scaffold, bio composite for wound healing and dressing, drug delivery system and blood purification [66]. Purification could be carried out both by membranes and microbead shaped composites [67,68]. ...
Polysaccharides arguably are the most diverse group of biopolymers on earth with critical roles in energy storage, cellular structure components and safekeeping of hereditary information. With the wide variety of structures, source organisms and years of evolutionary history in different habitats, these biomolecules encompass an array of derivatizations and conjugation with other biomolecules. This chapter would mainly focus on the major polysaccharides obtained from the marine environment, i.e. crustaceans, seaweeds, and microalgae. The polysaccharides will be discussed in context of their various properties and the applications for which they are or can be exploited in industries such as biomedical, pharmaceutical, agriculture, and food. This chapter summarizes the diversity of polysaccharides with the underlying basic principles and their versatile applications.
... BC is composed glucose, fructose, sucrose, mannitol and by arranged by nanofibers from 20 to 100 nm in diameter and the tensile strength up to 30 GPa [7,8]. BC had used as smart sensor [9], filtration membranes [10], electro-active paper sensor [11], implants [12], wound dressings [13], blood vessel grafts [14], tissue scaffolding [15], and packaging [16]. ...
This study aimed to identify the functional group of bacterial cellulose films (BCF) treated by alkali (NaOH) solution. The research methods were BCF production using medium culture based on pineapple peel juice. The resulted pellicle was immersed in the alkali of 0%, 1%, 5%, and 10%. Pellicle was dried in the oven to obtain BCF. Functional group of the sample was recorded by an FTIR instrument. BCF surface was observed by scanning electron microscopy. The result shows that structure of BCF contains cellulose I and cellulose II. The functional group of BCF before and after the treatment were at wave number 3400 cm ⁻¹ , 2900 cm ⁻¹ , 2133 cm ⁻¹ , 1635 cm ⁻¹ , 1373 cm ⁻¹ , 1067 cm ⁻¹ . Alkali treatment caused the peak band at 2135 cm ⁻¹ to be reduced due to the breaking of the triple bond of alkynes.
... Specifically, research in which affinity tags are engineered onto enzymes has permitted their rapid and facile immobilization onto their target support, including cellulose, silica and chitosan (Gilbert et al., 2013;Levy and Shoseyov, 2002). Enzyme immobilization on cellulose matrices has been extensively reported and reviewed in literature (Liu and Chen, 2016), due to its versatility and use in the medical, pharmaceutical and food industries (Sindhu et al., 2014;Javad and Khosro, 2013;Wuestenberg, 2014). Cellulose-based matrices are not only non-toxic, they are also abundant, inexpensive, and available in a range of morphologies (e.g. ...
Because of their potential impact in food and bioprocessing, diagnostics, green(er) chemistry, and waste remediation, new enzyme immobilization technologies continue to be explored. In this work, a recombinant lactase (β-galactosidase) (LacZ) presenting a carbohydrate binding module (LacZ-CBM), was engineered, expressed, and immobilized onto cellulose (LacZ-CBM:cell). Binding density, activity, and pH and temperature activity profiles were characterized in comparison to wild type lactase (LacZ). LacZ-CBM effectively self-immobilized onto cellulose (Sigmacell®) in less than 2 hours, demonstrating that recombinant enzymes with cellulose binding modules can enable immobilization onto solid supports without the need for chemical crosslinking agents. The immobilized recombinant LacZ-CBM:cell retained over 30% of its initial activity over 9 cycles. Both immobilized and non-immobilized LacZ-CBM presented similar optimum reaction conditions as wild type lactase, which demonstrates that the addition of a carbohydrate binding module (CBM) to lactase does not alter its optimum reaction conditions. This work has direct relevance to immobilized lactase applications (e.g. lactose reduced milk; oligosaccharide production) and serves as a model for other greener enzyme immobilization applications.
... The microfibrils of BC assemble to form large ribbon cellulose in the fermented medium [1]. Because of excellent properties, the BC becomes attractive for various applications [2] including biotechnological engineerings such as wound dressings [3], tissue scaffolding [4], blood vessel grafts [5], and implants [6], bio-based packaging [7] and smart sensor [8]. Although in many novel applications, BC shows potency as an excellent material, the high production cost and low yield inhibit industrial-scale production. ...
Properties of Bacterial Cellulose was depended on the fermentation conditions to produce BC as well as the processing steps for modifying the Bacterial Cellulose microstructure. This study reports on the comparison effect of drying method on Bacterial Cellulose films structure produced from Pineapple Peel Extract. The drying method was done in the oven and freeze-drying. Pellicle as results of fermentation by bacteria was dried in the oven. High-pressure homogenization was applied before the freeze-drying method. BC film structure was observed using scanning electron microscopy and evaluated using X-ray diffraction. The results show that the peak of diffractogram shows crystalline peaks in a relatively similar position, which are at about 14° and 22°. High-pressure homogenizer process before freeze-drying results the structure with higher crystalline compare than oven drying. The index of crystalline and degree of crystalline of BC film in the freeze-drying method were higher than those in the oven with a value of 83% and 86% compared than 81% and 84%, respectively. Drying methods to pellicle in the oven and freeze-drying results in the degree of crystalline of 79% and 71%, respectively. The morphology of the freeze-drying methods contains a
more porous structure.
... Cellulose is abundant in nature as it accounts for one-third of the Earth's vegetative matter [17], with an estimated worldwide production of 10 10 and 10 11 tons per year [18]. The application of cellulose has received considerable attention in fuel cells [19], biomedical engineering [20], wastewater treatment of textile industry [21] and food industry [22]. Figure 1 shows the chemical structure of cellulose which consists of repeating units of glucose, and it is a linear natural polymer consisting of 1,4-anhydro-D-glucopyranose units [23]. The beneficial properties of cellulose that include biocompatibility, abundance, renewability, biodegradability, non-abrasive nature in processing, and high specific mechanical strength amongst others make cellulose to be one of the most promising candidates for use in energy storage devices [24,25]. ...
CMC-NH2CH3CO2 complexes were characterized via theoretical and experimental approaches using molecular dynamics (MD) calculation, Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD), and electrical impedance spectroscopy (EIS) analysis. These analyses successfully disclosed the structural and ion conduction properties of the bio-polymer electrolytes (BPE) system. The FTIR analysis further revealed that an interaction exists between the carboxylate anion group (COO–) from CMC and the H+ substructure of NH4CH3CO2. The ionic conductivity value at ambient temperature was found to achieve an optimum value of 5.07×10–6 S/cm for a system containing 10 wt% NH2CH3CO2. The ionic conductivity improvement was demonstrated via the increment on the amorphous phase of the BPEs system as shown in the XRD analysis upon the inclusion of NH2CH3CO2. Based on the IR-deconvolution approach, the mobility (μ) and diffusion coefficient (D) were found to influence the ionic conductivity and aligned with the theoretical molecular dynamic (MD) calculation. To evaluate the potential application of the CMC-NH2CH3CO2, an electrical double-layer capacitor (EDLC) was fabricated from the BPE and tested using cyclic voltammetry (CV), and charge-discharge (GCD) for 300 cycles and the BPE exhibited a specific of capacitance ~2.4 F/g.
... The clinical application of cellulose-containing 3D scaffolds includes repair, reconstruction, and regeneration of almost all types of tissues in the mammalian organism; this polymer endows scaffolds with the ability to support cell adhesion and growth. In wound dressings, it is no accident that these cellulose-based materials have been used since the mid-1970s, in the form of cotton gauze or non-woven mixtures of rayon and polyester or cotton fibers, since they are capable of absorbing excess exudates through their bulk polar groups (-OH) and allow for the production of highly porous structures, permeable to air, steam, and heat, ensuring the patients comfort [83]. ...
Wound healing requires careful, directed, and effective therapies to prevent infections and accelerate tissue regeneration. In light of these demands, active biomolecules with antibacterial properties and/or healing capacities have been functionalized onto nanostructured polymeric dressings and their synergistic effect examined. In this work, various antibiotics, nanoparticles, and natural extract-derived products that were used in association with electrospun nanocomposites containing cellulose, cellulose acetate and different types of nanocellulose (cellulose nanocrystals, cellulose nanofibrils, and bacterial cellulose) have been reviewed. Renewable, natural-origin compounds are gaining more relevance each day as potential alternatives to synthetic materials, since the former undesirable footprints in biomedicine, the environment, and the ecosystems are reaching concerning levels. Therefore, cellulose and its derivatives have been the object of numerous biomedical studies, in which their biocompatibility, biodegradability, and, most importantly, sustainability and abundance, have been determinant. A complete overview of the recently produced cellulose-containing nanofibrous meshes for wound healing applications was provided. Moreover, the current challenges that are faced by cellulose acetate-and nanocellulose-containing wound dressing formulations, processed by electrospinning, were also enumerated.
... A citrate-based flexible optical sensor has been developed for medical applications for delivering light into the body (Shan et al. 2017). Cellulose materials have similar properties to the given materials since they are also body compatible already used in medical applications (Sindhu et al. 2014). The use of optical fibers in medical applications has been previously reviewed (Nazempour et al. 2018). ...
In this study an optical cellulose fiber for water sensoring was prepared by using a sequential preparation strategy. The core of the fiber was prepared from dissolved cellulose, in [EMIM]OAc, which was dry–wet spun into water. The cladding layer on the cellulose core was produced by coating a layer of cellulose acetate, dissolved in acetone, using a filament coater. The chemical and optical properties of both regenerated cellulose and cellulose acetate were studied from cast films using ultraviolet–visible and Fourier-transform infrared spectroscopy measurements. Regenerated cellulose film was observed to absorb UV light, passing the visible light wavelengths. Cellulose acetate film was observed to pass the whole light wavelength range. The mechanical strength and topography of the prepared optical cellulose fiber were investigated through tensile testing and SEM imaging. The mechanical performance of the fiber was similar to previously reported values in the literature (tensile strength of 120 MPa). The prepared optical fiber guided light in the range of 500–1400 nm. The attenuation constant of the cellulose fiber was observed to be 6.3 dB/cm at 1300 nm. The use of prepared optical cellulose fiber in a water sensor application was demonstrated. When the fiber was placed in water, a clear attenuation in the light intensity was observed. The studied optical fiber could be used in sensor applications, in which easy modifiability and high thermal resistance are beneficial characteristics.
Graphic abstract
Coaxial cellulose acetate-regenerated cellulose fiber for transporting light in sensor optical fiber sensor applications. Open image in new window
... Together with viscose, it is the one most used in the production of medical textiles (Ates & Cerkez, 2017;Bashar & Khan, 2012;Klemm, Heublein, Fink, & Bohn, 2005). As a biomaterial, cellulose can be converted into a wide range of derivatives with desired properties for a variety of medical applications, such as antimicrobial materials, gauzes, wound dressings, bandages, surgical covers, nappies, tampons, drug delivery matrices, or scaffolds in tissue engineering (Amalraj, Gopi, Thomas, & Haponiuk, 2018;Picheth et al., 2017;Sindhu, Prasanth, & Thakur, 2014). ...
Stability of cotton fibers oxidized by the 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO)-mediated system during natural aging was monitored; the oxidized and five-year-aged fibers were characterized in terms of molecular weight distribution, quantity and distribution of functionalities, tensile strength, color difference, and yellowness index. The distribution of functionalities introduced in cotton fibers by TEMPO-mediated oxidation and subsequent aging was investigated by means of gel permeation chromatography using multiple detection and group-selective labeling. The mild TEMPO-mediated oxidation retains the molar mass of oxidized cotton, but this status is not stable during natural aging. For highly oxidized cotton, the molar mass of aged fibers is low but stable. Aged TEMPO-oxidized cotton shows a prominent discoloration and an increased yellowness index. For tensile strength, the limiting value was obtained for aged TEMPO-oxidized cotton, regardless of whether the samples had initially been oxidized with a low or high degree of oxidation.
... An important development in that time is the understanding that maintaining a moist wound environment is conducive to healing [6], where the consensus was keeping the wound area dry was necessary. This is where cellulose has come into its own as a wound dressing, with its capacity to absorb large amounts of exudate but still maintain a moist environment [7]. Wounds such as diabetic ulcers found on lower limbs produce large amounts of exudate which must be managed to prevent necrosis and allow normal healing to proceed. ...
Cellulose is the most abundant polymer found on the face of the earth with plants and bacteria producing over 1011 103 kg every year. Not only is this material widely available, it is renewable, sustainable and cheap, making it an attractive selection across many industries. The return to naturally derived materials in the medical field is driven by two motivations; the increased cases of resistance in bacteria to conventional drugs, and more relatedly, the need to reduce dependence on non-renewable resources when producing medical materials. Cellulose and its derivatives, are already used widely in the biomedical field in varying applications; drug delivery to eye drops. When manufacturing biomaterials from cellulose, the techniques used usually contain many steps and can be quite costly, this is where electrohydrodynamic (EHD) processing comes in. EHD is a one step process where under the influence of an electric field, a polymer solution or melt can be processed into micro- and nano-scale structures as a function of the polymer solution/melt properties such as concentration, molecular weight, solvent and processing properties such as voltage, flow rate and collection distance. In the first instance, this work investigated the electrospinning of three cellulose derivatives, ethyl cellulose, cellulose acetate and carboxymethyl cellulose; changing parameters aforementioned and observing the effect on the microstructures produced. Bacterial cellulose produced by the Gluconacetobacter xylinus bacteria, is chemically identical to plant cellulose, but is purer, not needing any separation or purifying post production. The most attractive feature of this bacterial cellulose (BC) is its liquid absorption capacity, it can hold many times it weight in liquid and proves to be useful in managing the exudate of diabetic ulcers. This BC was blended with different polymers and anti-diabetic drugs, after which in vitro behaviour was assessed.
... Nanocellulose (NC) is a very attractive material due to its unique properties, i.e., lightweight, strength, flexibility, biodegradability and biocompatibility, wide availability and cost efficiency of the sources [1][2][3]. The increasingly severe environmental policies and the exceptional properties of NC promote it as a valuable material for a wide range of applications. ...
Tailoring the surface properties of nanocellulose to improve the compatibility of components in polymer nanocomposites is of great interest. In this work, dispersions of nanocellulose in water and acetonitrile were functionalized by submerged plasmas, with the aim of increasing the quality of this reinforcing agent in biopolymer composite materials. Both the morphology and surface chemistry of nanocellulose were influenced by the application of a plasma torch and filamentary jet plasma in a liquid suspension of nanocellulose. Depending on the type of plasma source and gas mixture the surface chemistry was modified by the incorporation of oxygen and nitrogen containing functional groups. The treatment conditions which lead to nanocellulose based polymer nanocomposites with superior mechanical properties were identified. This work provides a new eco-friendly method for the surface functionalization of nanocellulose directly in water suspension, thus overcoming the disadvantages of chemical treatments.
Vascular tissue engineering aims to create vessel models for in vitro research and develop vascular grafts for in vivo applications using tubular scaffolds. Natural scaffolds outperform synthetic ones due to their biocompatibility and natural microenvironment supporting cell growth. Given the importance of producing biocompatible tubular scaffolds through cost‐effective and uncomplicated processes, this study introduces nature‐derived tubular structures from three decellularized tubular plants (Water Spinach, Green Onion, and Water Horsetail) as novel alternatives. Microstructural characterization on the luminal surfaces of the plants reveals unique surface topography for each. Water Spinach is the most promising graft candidate in suturability tests besides presenting the highest elongation before rupture in tensile test. Assessment of human endothelial cells on the luminal surfaces of decellularized scaffolds shows higher expression of Ki‐67 protein and a consistent increase in cell number on water spinach and green onion scaffolds compared to tissue culture plate as a control. Focal adhesion‐related molecule Vinculin is expressed more than twice on all scaffolds compared to control, and confluent cell monolayers are formed on water spinach and green onion scaffolds, as confirmed by VE‐cadherin. This study proposes an innovative approach to use the natural structure of macro‐tubular plants for the preparation of vascular scaffolds.
The article describes the preparation of new cotton materials obtained by chemical deposition of copper sulfide. This two-stage process consists of chelation of copper sulfate on cellulose chains of cotton (COT → COT-CuSO4) with subsequent precipitation of copper in the form of copper sulfide (COT-CuSO4 → COT-CuS) using sodium sulfide. The obtained COT-CuS composites were characterized physicobiologically. Thus, the structural characteristic of the Cotton-CuS material was determined by microscopy analysis (SEM), Atomic Absorption Spectrometry with Flame Excitation (FAAS), specific surface area and total pore volume analysis (BET). The copper functionalized cotton fabric was subjected to microbial activity tests against colonies of Gram-negative (Escherichia coli) and Gram-positive ( Staphylococcus aureus) bacteria and Chaetomium globosum, Aspergillus niger fungal molds species. Biochemical evaluation includes hematological tests of activated partial thromboplastin time (aPTT) and prothrombin time (PT). The substantial antimicrobial properties of the newly synthesized COT-CuS material with the lack of influence on blood coagulation processes offer prospects of a potential use as applications as an antibacterial/antifungal material.
The paper presents the new eco-friendly method of bleaching process of the cellulose fibre materials. Cellulose materials were bleached using hydrogen peroxide (both in aqueous solution, vapours, ozone and by the combined action of gaseous hydrogen peroxide and ozone. The method using hydrogen peroxide in aqueous solution presents the standard procedure and was used as the comparison technique. The bleaching processes using gaseous oxidants were carried out in a prototype device for dry, low-temperature treatment of fibrous materials with the use of oxidising agents in the gas phase. The influence of the innovative gas-phase bleaching method on the cotton samples’ properties was analysed by Scanning Electron Microscopy (SEM), evaluation of the colour and whiteness, assessment of the polymerisation degree (DP), analysis of the mechanical properties and sorption capacity as well as microbiological assessment against colonies of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The comparison of the obtained results led to the conclusion that the bleaching processes using gas-phase agents—vaporised hydrogen peroxide, ozone or their combination—are non-invasive. The applied bleaching processes resulted in a slightly lower whiteness parameters than standard bath bleaching. After the bleaching processes with ozone and vaporised hydrogen peroxide separately, the decrease in the DP and tensile strength was similar to that observed after the bleaching with aqueous H2O2. When both processes were used together, a higher reduction in DP and tensile strength was noticed. Both oxidising agents showed a strong biocidal effect against bacteria. Gas-phase bleaching procedures, due to the lower temperature (35 °C vs. 98 °C) and minimal water consumption, have economic and environmental advantages, which allows their use in semi-industrial applications. It has been shown that the treatment of cotton fabrics using ozone and hydrogen peroxide in the gas phase allows to simultaneously obtain the bleaching and disinfection effect.
This volume is a comprehensive compilation of reviews that show how various waste products can be used to produce useful products. Thirteen chapters highlight the following topics:
- applications of plant-derived and fruit waste for value-added product formation;
- fuel and chemical production from lignin
- food waste bioconversion to high-value products
- organic residues valorization for value-added chemicals
- valorization of waste plastics to produce fuels and chemicals
- food valorization for bioplastic production and concepts of circular economy in the valorization process.
Chapters are written in an organized and strategic manner and also include the references from recent years. It will help students and researchers to quickly learn about modern waste valorization practices and advance their knowledge on the subject. The book is suitable as a reference for courses in environmental science, chemical engineering and agriculture. It also serves as a guide for trainees, managers and readers involved in waste management, sustainability and value-added product supply chains
Cellulose derivatives due to their biocompatibility, bioactivity and biomechanics are among the most used resources for biomedical applications. In this study mats using different amounts of cellulose acetate (CA)/polyvinylpyrrolidone (PVP)/ polyvinyl alcohol (PVA) of blended nanofibers were prepared via co-electrospinning technique by employing double nozzle for jetting solutions of CA/PVP and PVA, separately. The chemical structure, morphology, thermal stability and tensile analyses of the prepared nanofibrous samples were fully characterized. Moreover, MTT assay and cell culture studies using human skin fibroblast cell lines were also carried out to determine the cytocompatibility, viability and proliferation of the cells on the surface of the prepared scaffolds. To survey on the release kinetics, ex-vivo skin permeation studies were performed on the mat with the most suitable ratio, using Franz cell diffusion system. According to the obtained thermophysical and biological results, the synthesized electrospun nanofibrous mat unveil great potentials in biomedical applications especially in cell culture, tissue engineering and also as a drug loaded transdermal patch.
Uncontrolled hemorrhage is still the most common cause of potentially preventable death after trauma in prehospital settings. However, there rarely are hemostatic materials that can achieve safely and efficiently rapid hemostasis simultaneously. Here, new carbonized cellulose-based aerogel hemostatic material is developed for the management of noncompressible torso hemorrhage, the most intractable issue of uncontrolled hemorrhage. The carbonized cellulose aerogel is derived from the Agaricus bisporus after a series of processing, including cutting, carbonization, purification, and freeze-drying. In vitro, the carbonized cellulose aerogels with porous structure show improved hydrophilicity, good blood absorption, and coagulation ability, rapid shape recoverable ability under wet conditions. And in vivo, the carbonized aerogels show effective hemostatic ability in both small and big animal serious hemorrhage models. The amount of blood loss and the hemostatic time of carbonized aerogels are all better than the positive control group. Moreover, the mechanism studies reveal that the good hemostatic ability of the carbonized cellulose aerogel is associated with high hemoglobin binding efficiency, red blood cell absorption, and platelets absorption and activation. Together, the carbonized aerogel developed in this study could be promising for the management of uncontrolled hemorrhage.
The purpose of this project is to combine oxidized cellulose nanofibrils (toCNFs) and various β-cyclodextrins (β-CDs) to design improved materials for biomedical applications. The combination of toCNFs and β-CDs, although promising, faces some challenges, notably characterization of this association. Thus, this project aims at developing innovative materials combining toCNF and various β-CD derivatives, with the objective of characterizing the adsorption phenomena and improving drug release of poorly-water soluble active principal ingredient (API) and consequently prolonging antimicrobial properties. First, the production of toCNF/β-CD materials was reported, with an investigation on the impact of various process parameters on water sorption and mechanical properties. The adsorption of β-CDs was characterized via different experimental tools, and it was shown that β-CD derivatives adsorb up to 10 times more onto toCNF than β-CD. The formation of an inclusion complex between a model API and the various β-CDs was thoroughly characterized. Finally, the functionalization of toCNF with β-CDs showed improvement of the antimicrobial properties of films with increased efficiency for carboxymethylated-β-CD. The results of this project contribute to the knowledge on interaction of cyclodextrin and nanocellulosic materials and are a step-towards their efficient application in biomedical field as well as other applications such as depollution.Keywords: cellulose nanofibrils, β-cyclodextrins, adsorption characterization
Bacterial cellulose (BC), pure cellulose, has become a new material for cellulose-based products due to its unique properties such as high crystallinity, precise nanostructure, high biocompatibility, high mechanical strength, biodegradability, non-toxicity, 3-dimensional molding capacity, etc. In this study, the availability of Alcohol Lees, by-product of alcohol production as a cheap carbon and nitrogen source, was evaluated for bacterial cellulose production and then the BC was produced in layer-by-layer form with high productivity without any additives using an Intermittent Feeding Strategy. The synergic effects between Alcohol Lees dilution (60–100%), pH (3.5–7.5), Intermittent Feeding Height (0.5–2.5 mm), and Intermittent Feeding Interval (0–48 h) were analyzed for maximum BC production by respond surface methodology. The optimal condition for maximum BC production in the Intermittent Feeding Strategy were Alcohol Lee dilution (86.2%), pH (5.6), Intermittent Feeding Height (1.4 mm), Intermittent Feeding Interval (22.2 h) and its maximum BC yield was 4.41 ± 0.06 g L−1 compared to the conventional static culture of BC with 2.03 ± 0.05 g L−1 yield in 1-week-culture. BC produced either with HS medium or AL medium indicate similar characteristic figure in Fourier transform infrared spectra and scanning electron microscope and show similar crystalline structure but lower cellulose crystallinity in the AL sample (58.9%) compared to HS sample (63.9%) in X-ray diffraction. This work provides a potential opportunity to propose alternative medium and to highlight the availability of Alcohol Lee, food waste for BC production.
Biotextile-based products are widely used in medical implants and regenerative medicine due to their interconnectivity, large surface area, controlled mechanical strength, open pore structure and ease of modification. This chapter reviews the relevant fabrication technologies and types of polymers used to prepare biotextiles for clinical applications. The applications of biotextiles in several sectors of tissue engineering and medical implants have been described. Details about different biotextile products, their therapeutic applications as well as performance characteristics, current issues and shortcomings are highlighted. Biotextiles, both resorbable and nonresorbable, are used as surgical sutures, arterial prosthesis, prosthetic heart valve material, temporary blood filter, noninvasive biotextile-based closure devices for septal defects, wound dressing and so forth, and are discussed thoroughly. The challenges faced in designing and engineering biotextile products, such as the anterior cruciate ligament prosthesis are also covered. Future trends and scope for intensive research on applications of biotextiles have been discussed with reference.
In this work, cellulose nanofiber was prepared from water hyacinth (WH) using a simple domestic blender and employed as reinforcement in recycled paper. There are various sources to prepare cellulose nanofiber. However, water hyacinth was used as a source to synthesize cellulose in this study to decrease its devastating effect on the water body. Pure cellulose was isolated from water hyacinth with chemical treatments including dilute alkali swelling and bleaching. The chemical composition of water hyacinth was gravimetrically determined and the result demonstrated that cellulose is the largest constituent of the plant (55%), followed by hemicelluloses (19%) and lignin (14%). The remaining 12% was related to other extracts like fat, oil, pectin, etc. As the FTIR data revealed, the functional groups corresponding to lignin and hemicelluloses were absent in the FTIR spectra of extracted cellulose. To increase its functionality, the prepared cellulose was disintegrated into nanofibers using a simple mechanical treatment. To learn more about cellulose fibrillation, UV–Vis spectroscopy was used to analyze the light transmittance of 1 wt% water dispersed, mechanically treated cellulose. The dispersion showed high light transparency, particularly at a higher wavelength. As a result of the cellulose dispersion's reasonable light transmittance value, it can be deduced that the aggregated cellulose chains were efficiently transformed into nanofibers. The inclusion of cellulose nanofibers as reinforcement significantly improved recycled paper's moisture resistance, thermal stability, and mechanical strength.
The use of heterocyclic compounds is established as one of the most successful, economic and practical techniques of corrosion protection. The heterocyclic compounds develop into useful by adsorbing at the metal-environment interface using their electron dense centers, called adsorption centers. However, because of their relatively smaller size, they provide insufficient surface protection. More so, their synthesis is connected with the use of expensive and toxic chemicals, solvents and catalysts. Therefore, there is an extreme demand of ecofriendly alternatives of relatively bigger molecular size. In this direction, the use of natural and synthetic polymers as anticorrosive materials is gaining particular attention. Due to their polymeric nature and presence of polar functional groups at the periphery, the polymers effectively adsorb on the metallic surface and provide excellent surface protection. More so, the exercise of natural polymeric alternatives including carbohydrates, proteins and their derivatives offers a new alternative path to replace traditional toxic corrosion inhibitors. The present review paper aims to collect outcomes of major reports describing the corrosion inhibition potential of natural and synthetic polymers. Advantages of polymers over traditional corrosion inhibitors and the mechanism of corrosion inhibition using polymers have also been discussed.
Cellulose reinforced rubber composites generally consist of the matrix made from rubber and cellulose as reinforcement filler material. Rubbers are known as “elastomers,” a class of polymer which is amorphous with “elastic” properties, which are attributed to the notably low Young’s modulus and high yield strain (McKeen & McKeen, 2019). Elastomers could be categorized as thermoset elastomers and thermoplastic elastomer; depending on its ambient conditions, where they are relatively malleable. Some common examples of the different types of rubbers include:...
The largest group of chemicals that are currently used for the manufacturing of 3D-printed structures are synthetic polymers. Among those, the use of thermoplastics is very common, nearly exclusive, mainly because of the ease of their handling through melt processing. While in recent years, there has been a growing shift toward the use of biopolymers because of many attractive properties of those, traditional 3D printing methods from common solvents (such as volatile organic solvents, VOCs) or melts are not suitable for biopolymers. In fact, 3D printing of biopolymers is held back by the lack of suitable technology that would allow biopolymer liquefaction and layer-by-layer deposition in a liquid state, followed by solidification. The chapter focuses on recent advances in the 3D printing of cellulose and chitin realized by enabling technology based on a class of materials known as ionic liquids.
Cellulose is a versatile material with multiple derivatives and numerous composites. Owing to great biocompatibility, biodegradability, light weight, ample chemically modifying capacity, actuation capability, and eco-friendly nature of cellulose, nowadays natural resource-based renewable cellulosic biopolymers are being major contributors in the fabrication of green biocomposites. These composites have high potential applicability in the diversified arena of biomedical engineering and they are exhibiting excellent performance in terms of wound dressing, tissue engineering, and drug delivery. In this triumphant march of development, the nanoscale cellulosic composites having bacterial origin are leading the way. This chapter evaluates cellulose as a high-performance green biocomposite having zero impact on nature and focuses on its vast spectrum of current applications and emerging future prospects in biomedical engineering.
Suture materials constitute one of the largest biomedical material groups with a huge global market of $ 1.3 billion annually and employment in over 12 million procedures per year. Suture materials have radically evolved over the years, from basic strips of linen to more advanced synthetic polymer sutures. Yet, the journey to the ideal suture material is far from over and we now stand on the brink of a new era of improved suture materials with greater safety and efficacy. This next step in the evolutionary timeline of suture materials, involves the use of natural, carbohydrate polymers that have, until recent years, never before been considered for suture material applications. This review exposes the latest and most important advancements in suture material development while digging deep into how natural, carbohydrate polymers can serve to advance this field.
A wide range of platforms has been developed for 3D culture of cells in vitro to aggregate and align cells to resemble in vivo conditions in order to enhance communication between cells and promote differentiation. The cellulose skeleton of plant tissue can serve as an attainable scaffold for mammalian cells after decellularization, which is advantageous when compared to synthetic polymers or animal-derived scaffolds. Adjustable variables to modify the physical and biochemical properties of the resulting scaffolds include the protocol for the sodium dodecyl sulfate (SDS)-based decellularization procedure, surface coatings for cell attachment, plant type for decellularization, differentiation media, and integrity and shape of the substrate. These tunable cellulose platforms can host a wide range of mammalian cell types from muscle to bone cells, as well as malignancies. Here, fundamentals and applications of decellularized plant-based scaffolds are discussed. These biocompatible, naturally perfused, tunable, and easily prepared decellularized scaffolds may allow eco-friendly manufacturing frameworks for application in tissue engineering and organs-on-a-chip.
Development of sustainable green technologies and process becomes a key on sustainable society. Through sustainable development goals (SDGs) of United Nations, the purpose is trying to achieve better human life under low-carbon, circulation and natural symbiosis societies. Concepts of green chemistry and sustainable green technologies for developing advanced materials are important, for example, in recycle processes of waste materials and bio-based industries. This review highlights the role of SDGs on the material development and introduces examples for cases of recycling with plant wastes or uses of green chemicals for functionally advanced materials. Since such way is able to reduce environmental load, the recent trends survey in the point of views of SDGs for advanced materials and sustainable green technologies, especially for the 9 SDGs as explained for industry, innovation and infrastructure.
Thanaka heartwood, which was biomass waste after using the bark of thanaka, was recycle-used for thanaka cellulose films and then applied for cosmetic facial masks. The thanaka heartwood composed of cellulosic fibers and the ordered whewellite (hydrated calcium oxalate) was chemically treated, and the processes could remove lignin, hemicelluloses, whewellite, and others successfully by using acid (H2SO4), alkali (NaOH) and sodium hypochlorite (NaOCl). Dimethylacetamide/lithium chloride (DMAc/LiCl) solution was used to dissolve the thanaka cellulose fibers, and then cellulose hydrogel films having transparent and flexible were prepared. Antimicrobial activities of cellulose solutions were tested for the purpose of using thanaka cellulose films for facial masks. From those observations, thanaka cellulose hydrogel films and facial masks are potential to be environmental friendly and biocompatible products.This article also has reviewed cellulosic hydrogels for uses of cosmetic application.
A novel nanocomposite material consisting of hydroxyapatite (HAp) deposited on a phosphorylated bacterial cellulose (BC) has been synthesised via a biomimetic route. X-ray photoelectron spectroscopy (XPS) showed that phosphate groups were successfully introduced to the hydroxyl groups of BC by phosphorylation reaction to promote the growth of calcium phosphate. Transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED) patterns of HAp/BC demonstrated that HAp crystals wrap the surfaces of BC fibres. In this work, HAp/BC nanocomposites were studied using thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA result suggested that HAp/BC nanocomposite, similar to natural bone in terms of composition, contained carbonate ions, in agreement with our previous Fourier transform infrared (FTIR) spectroscopy results. Thermal behaviour differences between BC and HAp/BC were observed by differential scanning calorimetry (DSC). The thermal stability of HAp/BC obtained from DSC showed an improvement when compared to that of a pure BC sample.
Com o objetivo de comparar a ação de diferentes agentes terapêuticos promotores da cicatrização da pele, foi realizado um estudo clínico, histopatológico e morfométrico em suíno. Utilizou-se seis animais mestiços provenientes de uma mesma leitegada com 90 dias de idade. Foram produzidas seis lesões experimentais quadrangulares do mesmo tamanho na região dorso-lombar e uma delas permaneceu como controle. Em cada animal, foram testados cinco tratamentos: Biofill humano, Biofill veterinário, Tegaderm, Duoderm e Nitrofurazona. Foram realizadas biópsias aos 7, 14, 21, 45 e 60 dias da evolução cicatricial, seguidas de análise histopatológica. No período de 7 a 45 dias, realizou-se morfometria - perímetro e superfície inscrita - dos leitos cicatriciais. Foram as seguintes as membranas, pela ordem de eficiência, não só quanto à cicatrização mas também com relação à adesão ao leito da ferida: Biofill Humano, Biofill Veterinário, Tegaderm e Duoderm. A Nitrofurazona comportou-se, em relação ao aspecto cicatricial, de uma forma muito próxima à do Biofill; contanto, a necessidade de trocas diárias de curativos tornou o tratamento difícil. Abstract In order to compare different skin healing promoters, it was conducted a clinical, histopathological and morphometric study in swine. Six cross bred 90 days old animals from the same parturition were employed. Six experimental quadrangular wounds were made over the back region of each animal, one of them remaing as control. Five treatments were tested: Human Biofill, Veterinary Biofill, Tegaderm, Duoderm and Nitrofurazone At days 7, 14, 21, 45 and 60, biopsies for histopathological analysis were carried out. From de 7th to the 45th day, a morphometric study (perimeter and area) of the healing wounds beds was achieved. With the criteria of healing quality and adhesion to the wound the occlusive dressings in order of efficiency were: Human Biofill, Veterinary Biofill, Tegaderm and Duoderm. Nitrofurazone showed good healing qualities needing however daily changes of dressings.
Cited By :9, Export Date: 21 July 2015, CODEN: RPSPF, Correspondence Address: De Andrade, D.; Dept. of General/Specialized Nursing, Campus da USP, Av. Bandeirantes 3900, 14040-902, Ribeirao Preto, SP, Brazil; email: dandrade@glete.eerp.usp.br, Chemicals/CAS: Culture Media; Disinfectants; Phenols, References: Scarpitta, C.R.M., Limpeza e desinfecção de artigos hospitalares - Limpeza e desinfecção de áreas hospitalares (1997) Infecções Hospitalares - Prevenção e Controle, pp. 411-421. , Rodrigues EAC et al. São Paulo: Sarvier;
Bacterial cellulose, an exopolysaccharide produced by some bacteria, has unique structural and mechanical properties and is highly pure as compared to plant cellulose. This article presents a critical review of the available information on the bacterial cellulose with special emphasis on its fermentative production and applications. Information on the biosynthetic pathway of bacterial cellulose, enzymes and precursors involved in bacterial cellulose synthesis has been specified. Characteristics of bacterial cellulose with respect to its structure and physicochemical properties are discussed. Current and potential applications of bacterial cellulose in food, pharmaceutical and other industries are also presented.
Hydroxyapatite (HAp)/bacterial cellulose (BC) nanocomposites were prepared by an optimal biomimetic mineralization synthesis approach for bone tissue engineering application. BC with ultrafine three dimensional network was negatively charged by the adsorption of polyvinylpyrrolidone (PVP) to initiate the nucleation of HAp. The HAp was grown in vitro along the nanofiber network of BC via dynamic simulated body fluid (SBF) treatment. It was found that rod-like HAp particles in the nano-scale (100–200 nm) homogeneously deposited on the surface of PVP-BC. ATR-Fourier Transform Infrared Spectroscopy (ATR-FTIR) results showed that carbonate-containing HAp crystals resembling natural bones were formed by biomimetic mineralization method. Moreover, the amount of HAp observed increased with increasing mineralization time. And the Ca/P overall ratio ranged from 1.37 to 1.59. The results from Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) indicated that PVP treatment enhanced the apatite nucleation ability of BC with higher HAp deposit amount.
This article presents a study about the synthesis of colloidal silver (Ag)/biopolymer where Ag submicron particles were prepared in situ on bacterial cellulose (BC) produced by Gluconacetobacter xylinus. Different reducing agents were compared (hydrazine, hydroxylamine or ascorbic acid) together with the influence of gelatin or polyvinylpyrrolidone (PVP) employed as colloid protectors. Particle size distribution and morphology were investigated by scanning electron microscope (SEM). SEM images show silver nanoparticles (40–100 nm) size range attached on (BC) microfibrils. XRD analyses confirmed the Ag cubic phase deposited on to BC fibrils. The ash contents determined by thermogravimetric analyses have indicated high level of silver loading on the obtained composites.
A facile method was developed to prepare a magnetic Ag nanocomposite. The 3-D nanofibrous structure of bacterial cellulose (BC) was homogenized with a ferric and ferrous mixture by a high speed blender. Magnetite nanoparticles were precipitated and incorporated into BC nanostructure by adjusting the homogenate to alkaline pH. The magnetic BC nanofiber soaked in dopamine solution will be coated with an adherent self-polymerized polydopamine layer. Since the polydopamine surface is very effective for reducing silver ion, Agnanoparticles were incorporated into the dopamine treated magnetic BC by soaking in silver nitrate solution. The magnetization of the as-prepared Ag nanocomposite was well maintained. The magnetic Ag nanocomposite possesses a high antimicrobial activity against the model microbes Escherichia coli and Bacillus subtilis. It also has potential as a mild fermentation medium sterilizing agent that a freshly prepared LB medium shows no appreciable contamination after incubating with Ag nanocomposite for 4 h and removed by an external magnet.
A simple method was developed to load a large amount of silver nanoparticles into bacterial cellulose (BC) produced by Gluconacetobacter xylinus in a controlled manner. Due to the high electron-rich oxygen density in the BC macromolecules and the large surface area of the BC nanoporous structure as an effective nanoreactor, the in situ direct metallization technique was successfully used to synthesize Ag nanoparticles with an average diameter of 30nm and a loading content of at least 5 wt. (%), approximately. This novel procedure provides an easy and economical way to manufacture Ag nanoparticles supported on a porous membrane for various biomedical applications. These composite fibers showed nearly 100% antibacterial activity (elimination of microorganisms) against Escherichia coli because of the presence of the silver nanoparticles.
Introduction
Current therapies for articular cartilage defects fail to achieve qualitatively sufficient tissue regeneration, possibly because of a mismatch between the speed of cartilage rebuilding and the resorption of degradable implant polymers. The present study focused on the self-healing capacity of resident cartilage cells in conjunction with cell-free and biocompatible (but non-resorbable) bacterial nanocellulose (BNC). This was tested in a novel in vitro bovine cartilage punch model.
Methods
Standardized bovine cartilage discs with a central defect filled with BNC were cultured for up to eight weeks with/without stimulation with transforming growth factor-β1 (TGF-β1. Cartilage formation and integrity were analyzed by histology, immunohistochemistry and electron microscopy. Content, release and neosynthesis of the matrix molecules proteoglycan/aggrecan, collagen II and collagen I were also quantified. Finally, gene expression of these molecules was profiled in resident chondrocytes and chondrocytes migrated onto the cartilage surface or the implant material.
Results
Non-stimulated and especially TGF-β1-stimulated cartilage discs displayed a preserved structural and functional integrity of the chondrocytes and surrounding matrix, remained vital in long-term culture (eight weeks) without signs of degeneration and showed substantial synthesis of cartilage-specific molecules at the protein and mRNA level. Whereas mobilization of chondrocytes from the matrix onto the surface of cartilage and implant was pivotal for successful seeding of cell-free BNC, chondrocytes did not immigrate into the central BNC area, possibly due to the relatively small diameter of its pores (2 to 5 μm). Chondrocytes on the BNC surface showed signs of successful redifferentiation over time, including increase of aggrecan/collagen type II mRNA, decrease of collagen type I mRNA and initial deposition of proteoglycan and collagen type II in long-term high-density pellet cultures. Although TGF-β1 stimulation showed protective effects on matrix integrity, effects on other parameters were limited.
Conclusions
The present bovine cartilage punch model represents a robust, reproducible and highly suitable tool for the long-term culture of cartilage, maintaining matrix integrity and homoeostasis. As an alternative to animal studies, this model may closely reflect early stages of cartilage regeneration, allowing the evaluation of promising biomaterials with/without chondrogenic factors.
New nanocomposite films based on different chitosan matrices (two chitosans with different DPs and one water soluble derivative) and bacterial cellulose were prepared by a fully green procedure by casting a water based suspension of chitosan and bacterial cellulose nanofibrils. The films were characterized by several techniques, namely SEM, AFM, X-ray diffraction, TGA, tensile assays and visible spectroscopy. They were highly transparent, flexible and displayed better mechanical properties than the corresponding unfilled chitosan films. These new renewable nanocomposite materials also presented reasonable thermal stability and low O2 permeability.
Coating of ZnO nanoparticles on paper surface has potential technological applications. With this motivation, a simple approach of ultrasound assisted coating of paper with ZnO nanoparticles (y20 nm) without the aid of binder is reported for the first time in this work. The ultrasound assisted coating approach concurs with ''green'' chemistry as it is simple and environmentally friendly. Scanning electron microscope is used to characterize the surface morphology showing ZnO nanoparticles bound to cellulose fibers. Further characterization of coated surface is performed by attenuated total reflectance-Fourier transform infrared, X-ray diffraction, and time-of-flight secondary ion mass spectrometry in positive ion detection mode along with its imaging capability. The effect of ultrasound irradiation time on ZnO nanoparticles loading is estimated by thermogravimetric analysis. A plausible coating mechanism is proposed. The ZnO nanoparticles coated paper is found to possess antibacterial activity against Escherichia coli 11634.
Bacterial cellulose (BC)/Chitosan (Ch) composite has been successfully prepared by immersing wet BC pellicle in Ch solution
followed by freeze-drying process. The morphology of BC/Ch composite was examined by scanning electron microscope (SEM) and
compared with pristine BC. SEM images show that Ch molecules can penetrate into BC forming three-dimensional multilayered
scaffold. The scaffold has very well interconnected porous network structure and large aspect surface. The composite was also
characterized by Fourier transform infrared spectrum, X-ray diffraction, thermogravimetric analysis and tensile test. By incorporation
of Ch into BC, crystallinity tends to decrease from 82% to 61%, and the thermal stability increases from 263°C to 296°C.
At the same time, the mechanical properties of BC/Ch composite are maintained at certain levels between BC and Ch. The biocompatibility
of composite was preliminarily evaluated by cell adhesion studies. The cells incubated with BC/Ch scaffolds for 48h were
capable of forming cell adhesion and proliferation. It showed much better biocompatibility than pure BC. Since the prepared
BC/Ch scaffolds are bioactive and suitable for cell adhesion, these scaffolds can be used for wound dressing or tissue-engineering
scaffolds.
KeywordsBacterial cellulose–Chitosan–Scaffold–Mechanical properties–Cell adhesion
Bacterial cellulose (BC)/poly(ethylene glycol) (PEG) composite was prepared by immersing wet BC pellicle in PEG aqueous solution
followed by freeze-drying process. The product looks like a foam structure. The morphology of BC/PEG composite was examined
by scanning electron microscope (SEM) and compared with pristine BC. SEM images showed that PEG molecules was not only coated
on the BC fibrils surface but also penetrated into BC fiber networks. It has very well interconnected porous network structure
and large aspect surface. The composite was also characterized by Fourier transform infrared spectrum, X-ray diffraction,
thermogravimetric analysis (TGA) and tensile test. It was found that the presence of PEG affected the preferential orientation
of the (1[`1]0 1\bar{1}0 ) plane during the drying process of BC pellicle, which in turn decrease the crystallinity of dried BC. The TGA result showed
that the thermal stability was improved from 263 to 293°C, which might be associated with strong interaction between BC and
PEG. Tensile test results indicate that the Young’s modulus and tensile strength tend to decrease. Biocompatibility of composite
was preliminarily evaluated by cell adhesion studies using 3T3 fibroblast cells. The cells incubated with BC/PEG scaffolds
for 48h were capable of forming cell adhesion and proliferation, which showed much better biocompatibility than the pure
BC. The prepared BC/PEG scaffolds can be used for wound dressing or tissue-engineering scaffolds.
Bacterial cellulose was produced by Acetobacter xylinum (strain TISTR 975). Bacterial cellulose is an interesting material for using as a wound dressing since it provides moist environment to a wound resulting in a better wound healing. However, bacterial cellulose itself has no antimicrobial activity to prevent wound infection. To achieve antimicrobial activity, silver nanoparticles were impregnated into bacterial cellulose by immersing bacterial cellulose in silver nitrate solution. Sodium borohydride was then used to reduce the absorbed silver ion (Ag+) inside of bacterial cellulose to the metallic silver nanoparticles (Ag0). Silver nanoparticles displayed the optical absorption band around 420 nm. The red-shift and broadening of the optical absorption band was observed when the mole ratio of NaBH4 to AgNO3 (NaBH4:AgNO3) was decreased, indicating the increase in particle size and particles size distribution of silver nanoparticles that was investigated by transmission electron microscope. The formation of silver nanoparticles was also evidenced by the X-ray diffraction. The freeze-dried silver nanoparticle-impregnated bacterial cellulose exhibited strong the antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive).
Venous ulceration, a relative common manifestation of chronic venous insufficiency and venous hypertension, is often difficult to treat. Successful treatment begins with the management of the underlying pathology and wound bed preparation. This article reports the authors' experience with a novel wound dressing produced from microbial cellulose synthesized by an acid-producing bacterium, Acetobacter xylinium. Twenty-four patients with chronic venous insufficiency and lower-leg ulceration were treated with either biocellulose wound dressing (BWD) plus a two-layer compression bandage or standard care. Standard care consisted of a nonadherent primary wound dressing plus a two-layer compression bandage. Evaluations were performed weekly to measure wound pain, nonviable tissue reduction, degree of wound granulation, and wound healing (reduction in wound size and surface area). BWD was significantly more effective than standard care for autolytic debridement (reduction in the amount of nonviable tissue [p=0.0094]). The mean number of days to >75-percent granulation was 43 days for the BWD treated group and 71 for the standard care group. Mean percent reduction in wound area was also greater for the BWD treated group at Week 6 (39% vs. 19%) and at Week 12 (74% vs. 49%). When compared to patients treated with standard care, the group treated with BWD reported less wound pain at each evaluation point. Significant differences in wound pain scores between the two treatments were noted at Week 3, 6 (p=0.039), and 8 (p=0.043).
The artificial kidney is a dialysing-apparatus with a small blood volume and a dialysing area of about 20,000 sq. cms., in which the blood of a patient is cleared of retention products. With one patient 24, 40, and 35 grams of urea could be dialysed out in 1.5, 4, and 6 hours respectively. Other retention products were removed by dialysis as well. This could be demonstrated for: rest N, urea, uric acid, creatinine and indoxyl. We believe to be able to keep patients suffering from uremia and anuria alive so long as bloodvessels for punction are available. In the case of acute uremia the possibility exists for the kidneys to regenerate in the meantime. Sulfamethylthiazol and other substances with small molecules (poisons!) may be removed by dialysis as well. Post Scriptum at the time of correction, January the 15th, 1944. In table 5 the high value of 748 (check 750) mg% of NaCl is probably caused by infusion of saline a short time before the sample for determination was taken. Further analysis of the rinsing fluid after dialysis no. X gave the following results: 70 litres of bath water contained 42 mg of magnesium, 25 mg of phosphorus and 210 mg of potassium. Two more patients have been treated with the artificial kidney, both were from a clinical point of view hopeless cases; 1. a man suffering from cachexia and uremia due to bilateral renal tuberculosis. 32 grams of urea were removed by one dialysis; on the next day he passed more urine than before the dialysis. 2. a man with an acute glomerulo-nephritis and oliguria, one of whose kidneys had been decapsulated without success. He passed into collapse and coma a few hours before the dialysis, from which he did not awake. 100 grams of urea were removed in 6 hours, the urea contents of the patient's blood showing a decline from 460 to 290 mg%. In order to prevent thrombosis in the needles it proved advisable to start heparinisation 2 or 3 hours before the dialysis, by giving 200, 100 and 100 mg of héparine at hourly intervals.
Zusammenfassung
Ziel: Untersuchung der Wirkung einer topischen Behandlung nicht heilender venöser Beinulzera. Patienten, Methoden: Die 54 in die Studie aufgenommenen Patienten wurden in zwei Gruppen unterteilt. Gruppe 1: 27 Patienten (Größe der Ulzeration: 16,8 - 34,8 cm2; Ulkusalter: 7 Monate bis 9 Jahre) wurden unter Verwendung von Zellulosemembran behandelt. Gruppe 2: 27 Patienten (Größe der Ulzeration 14,6 – 33,2 cm2; Ulkusalter: 9 Monate bis 8 Jahre) wurden unter Verwendung eines Unna-Schuhs behandelt. Es wurden beide Methoden zur Therapie nicht heilender venöser Beinulzera verglichen. Ergebnisse: Bei 15 Patienten aus Gruppe 1 heilte das Ulkus nach 8 Wochen unter therapeutischer Anwendung der Zellulosemembran vollständig ab. Die Ulzera der übrigen Patienten heilten innerhalb der folgenden 6 Wochen. Bei 4 Patienten aus Gruppe 2 war der Heilungsprozess nach 8 Wochen erfolgreich abgeschlossen. Bei den anderen Patienten dieser Gruppe dauerte die Heilung 20 Wochen. Schlussfolgerungen: Wir stellten fest, dass die Zellulosemembran im Vergleich zum Unna- Schuh eine wirksamere Behandlungsmethode chronischvenöser Beinulzera darstellt.
In order to determine of the osmotic-diffusive properties of membranous dressing Bioprocess, which is a microfibrous network of homogeneous cellulose produced in biosynthesis by Acetobacter, the hydraulic permeability (Lp), reflection (sigma) and diffusive permeability (omega) coefficients were measured. The values of these coefficients showed that this membrane possess a low selectivity. This amount it easy permeable for solvent (water) as well as for solutions (aqueous solutions of glucose, sucrose, ethanol, NaCl or KCl). Thus, it attend a demands make for polymeric materials used in therapy of scald and ulceration.
THE USE of nonabsorbable suture material in surgery is more and more encroaching on the domain of surgical gut. Long ago Kocher1 and Halsted2 focused attention on the use of silk, while Meade and Ochsner3 and Meade and Long4 have demonstrated the superiority of cotton. More recently Whipple,5 Shambaugh,6 Hyde7 and others have advocated the use of nonabsorbable sutures.
Of the various materials belonging to this group, cotton has gained the greatest popularity, its only drawback being the relatively low tensile strength. Size for size, dry surgical gut is the strongest suture material, with silk, linen and cotton following in order. Cotton, size for size, is two thirds as strong as surgical gut and three fourths as strong as silk.3b The tensile strength of a suitably twisted high grade egyptian cotton remains below that of true Bombyx mori silk. The "United States
N,N′-Bis(benzoyl) suberic acid dihydrazide (NA) as nucleating agent for poly(L-lactic acid) (PLLA) was synthesized from benzoyl hydrazine and suberoyl chloride, which was deprived from suberic acid via acylation. PLLA/NA samples were prepared by melt blending and a hot-press forming process. The nonisothermal and isothermal crystallization, spherulite morphology, and melting behavior of PLLA/NA with different contents of NA were investigated with differential scanning calorimetry, depolarized-light intensity measurement, scanning electron microscopy, polarized optical microscopy, and wide-angle X-ray diffraction. With the incorporation of NA, the crystallization peak became sharper and shifted to a higher temperature as the degree of supercooling decreased at a cooling rate of 1°C/min from the melt. Nonisothermal crystallization indicated that the presence of NA accelerated the overall PLLA crystallization. In isothermal crystallization from the melt, the presence of NA affected the isothermal crystalline behaviors of PLLA remarkably. The addition of NA led to a shorter crystallization time and a faster overall crystallization rate; this meant that there was a heterogeneous nucleation effect of NA on the crystallization of PLLA. With the addition of 0.8% NA, the crystallization half-time of PLLA/NA decreased from 26.5 to 1.4 min at 115°C. The Avrami theory was used to describe the kinetics of isothermal crystallization of the PLLA/NA samples. Also, with the presence of NA, the spherulite number of PLLA increased, and the spherulite size decreased significantly. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Bacterial cellulose has attracted increasing attention as a novel wound dressing material, but it has no antimicrobial activity, which is one of critical skin-barrier functions in wound healing. To overcome such deficiency, we developed a novel method to synthesize and impregnate silver nanoparticles on to bacterial cellulose nanofibres (AgNP-BC). Uniform spherical silver nano-particles (10-30nm) were generated and self-assembled on the surface of BC nano-fibers, forming a stable and evenly distributed Ag nanoparticles coated BC nanofiber. Such hybrid nanostructure prevented Ag nanoparticles from dropping off BC network and thus minimized the toxicity of nanoparticles. Regardless the slow Ag(+) release, AgNP-BC still exhibited significant antibacterial activities with more than 99% reductions in Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Moreover, AgNP-BC allowed attachment and growth of epidermal cells with no cytotoxicity emerged. The results demonstrated that AgNP-BC could reduce inflammation and promote wound healing.
A bacterial cellulose—chitosan (BC—Chi) composite has been successfully prepared by immersing wet BC pellicle in chitosan acetic acid solution followed by freeze-drying. By changing chitosan concentration and immersion time, a foam-like structure is made with the chitosan content in the range of 12—45 per cent. Scanning electron microscope images show that chitosan molecules can penetrate into BC forming a multi-layer structure. This foam has a very well interconnected porous network structure. The X-ray diffraction patterns indicate that with the increase in chitosan content, the crystalline structure is not changed but the crystallinity index tends to decrease. The thermal degradation temperature increases from 263 to 366 °C with the chitosan content increasing from 12 to 45 per cent. The tensile test results show that the tensile strength and Young's modulus of BC—Chi composites tend to decrease with the increase in chitosan content but the value is much higher than that of pure chitosan. This improved elasticity of the BC—Chi composites is important for biomedical applications.
Bacterial cellulose/fibrin composites were treated with glutaraldehyde in order to crosslink the polymers and allow better match of the mechanical properties with those of native small-diameter blood vessels. Tensile and viscoelastic properties of the glutaraldehyde treated composites were determined from tensile static tests and cyclic creep tests, respectively. Glutaraldehyde-treated (bacterial cellulose) BC/fibrin composites exhibited tensile strength and modulus comparable to a reference small-diameter blood vessel; namely a bovine coronary artery. However, the breaking strain of the glutaraldehyde-treated composites was still well below that of the native blood vessel. Yet a long strain hardening plateau was induced by glutaraldehyde treatment which resembled the stress–strain response of the native blood vessel. Tensile cyclic creep test indicated that the time-dependent viscoelastic behavior of glutaraldehyde-treated BC/fibrin composites was comparable to that of the native blood vessel. Covalent bonding between BC and fibrin occurred via glutaraldehyde, affording mechanical properties comparable to that of the native small blood vessel.
In situ synthesis of silver chloride (AgCl) nanoparticles was carried out under ambient conditions in nanoporous bacterial cellulose (BC) membranes as nanoreactors. The growth of the nanoparticles was readily obtained by alternating dipping of BC membranes in the solution of silver nitrate or sodium chloride followed by a rinse step. X-ray diffraction (XRD) patterns indicated the existence of AgCl nanoparticles in the BC and scanning electron microscopy (SEM) images showed that the AgCl nanoparticles well dispersed on the surface of BC and penetrated into the BC network. The AgCl nanoparticle-impregnated BC membranes exhibited high hydrophilic ability and strong antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The preparative procedure is facile and versatile, and provides a simple route to manufacturing of useful antimicrobial membranes, which would be a good alternative for antimicrobial wound dressing.
The biomedical applications of bacterial cellulose (BC) as a dressing material are mainly dependent on its water holding capacity (WHC) and water release rate (WRR), which in turn depend on pore size, pore volume and surface area. In the present study, the effects of structural modifications (in situ and ex situ) of BC on the WHC and WRR were investigated. The in situ modified BC was produced by the addition of various concentrations of a single sugar α-linked glucuronic acid-based oligosaccharide (SSGO) to the culture media while the ex situ modifications were carried out by preparing BC composites with chitosan (Ch) and montmorillonite (MMT). The morphological characteristics of the modified BC samples were studied with FE-SEM while their pore size, pore volume and surface area were determined through BET analysis. The results showed modifications in micro-fibril arrangements, pore size, pore volume and surface area in all BC samples compared to the control. The in situ modified BC showed denser fibril arrangement and decreasing pore size and pore volume with increasing SSGO concentration. Pore size and volume were also reduced in BC composites, probably due to the filling of pores by MMT and Ch. The variations in the WHC and WRR of BC samples were correlated to changes in various parameters after structural modifications. The WHC and WRR increased with pore volume and pore size in in situ modified BC samples. In ex situ modified BC, the WHC and WRR were dependent on the nature and arrangement of the composite materials on the surface and in the matrix of the BC sheets.
Nanocellulose (bacterial cellulose, BC), such as that produced by Acetobacter xylinum, has shown promising results as a replacement material for small diameter vascular grafts. The surface morphology of the lumen and mechanical properties of such tubes are crucial for their performance. The growth of a BC tube in a vertical fermentation bioreactor using silicone tubing for support and as an oxygen delivery membrane has not been studied in detail previously. Oxygen concentration and the number of bacteria added influence the production of the BC tubes. A dense and smooth luminal surface was formed after 4days on a 3mm silicone support. The bacteria were found to be in high concentration close to the silicon support and decreased in number further away. In the region with a high bacteria concentration, dense thin layers of BC were formed since the bacteria moved close together in this region. The presented observations were summarized in a theoretical model of BC tube growth.
Bacterial cellulose (BC), a natural nanoporous matrix, was utilized as the template to in situ synthesize silver nanoparticles (AgNPs) by chemical reduction. Effects of the microstructure of the BC template, produced by different fermentation carbon sources were investigated on the formation of AgNPs. A detailed characterization, e.g. SEM, XRD and nitrogen physisorption for pure BC, and EDX, UV–vis spectroscopy, TEM and inductively coupled plasma for the AgNPs impregnated BC composites (BC/AgNPs) were done, and the antimicrobial activity of every composite was evaluated by both zone of inhibition and log reduction methods. It was revealed that the particle size of AgNPs, and the silver content and antimicrobial activity of the BC/AgNPs composites varied depending on the different BC templates used, mainly due to the differences in the microstructure of the BC template, especially the crystallinity and porous properties. As far as we know, little studies have been done on this issue.
The in vitro degradation and cytotoxicity of bacterial cellulose (BC) and its degradation products were studied for potential applications in bone tissue engineering. Emission scanning electron microscope was used to observe the morphology of original materials and their degradation products. The degradation was evaluated by measuring the concentration of reducing sugar by using ultraviolet spectrophotometer. Bone forming osteoblast (OB) cells and infinite culture cell line L929 fibroblasts were used to measure the cytotoxicity of materials using the MTT assay. Both types of cells proliferated normally with the BC and its degradation products with a cytotoxicity graded of 0—1. Nevertheless, the bone-forming target OB cells were more susceptible to cytotoxicity than the infinite culture fibroblast cells L929 fibroblasts. The results indicate that the BC is not very cytotoxic and that tissue functional cells are more suitable for evaluating the cytotoxicity of biomedical materials.
Bacterial cellulose (BC) and bacterial cellulose-chitosan (BC-Ch) membranes were successfully produced in large scale. BC was synthesized by Acetobacter xylinum. BC-Ch was prepared by immersing BC in chitosan followed by freeze-drying. The surface morphology of BC and BC-Ch membranes were examined by a scanning electron microscope (SEM). SEM images showed that BC-Ch possessed a denser fibril network with smaller pores than BC. Infrared spectroscopy was used to confirm the incorporation of chitosan in BC-Ch. The swelling behavior, water retention capacity, and mechanical properties of BC and BC-Ch were further evaluated. Results indicated that both membranes maintained proper moisture contents for an extensive period without dehydration. The tensile strength and elongation at break for BC-Ch were slightly lower while the Young's modulus was higher. Cell culture studies demonstrated that BC and BC-Ch had no cytotoxicity. In the antibacterial test, the addition of chitosan in BC showed significant growth inhibition against Escherichia coli and Staphylococcus aureus. The effects of BC and BC-Ch on skin wound healing were assessed by rat models. Histological examinations revealed that wounds treated with BC-Ch epithelialized and regenerated faster than those treated with BC or Tegaderm. Therefore, BC-Ch was considered as a potential candidate for wound dressing materials.
Novel poly(3-hydroxyoctanoate), P(3HO), and bacterial cellulose composites have been developed. P(3HO) is hydrophobic in nature whereas bacterial cellulose is extremely hydrophilic in nature. Therefore, homogenized bacterial cellulose has been chemically modified in order to achieve compatibility with the P(3HO) matrix. Modified bacterial cellulose microcrystals and P(3HO) have been physically blended and solvent casted into two-dimensional composite films. Mechanical characterization shows that the Young's modulus of the P(3HO)/bacterial cellulose composites is significantly higher in comparison to the neat P(3HO) film. The melting temperature (Tm) of the composites is lower while the glass transition temperature (Tg) is higher than the neat P(3HO) film. Also, the composite film has a rougher surface topography as compared to the neat P(3HO) film. A month's in vitro degradation study has been carried out in Dulbeccos modified eagle medium and in phosphate buffer saline. The incorporation of modified bacterial cellulose microcrystal in the P(3HO) film has increased the degradability of the composite film. Finally, in vitro biocompatibility studies using human microvascular endothelial cells established the biocompatibility of the P(3HO)/bacterial cellulose microcrystal films. The cell proliferation was 50–110% higher on the P(3HO)/bacterial cellulose composites as compared to the neat P(3HO) film. Hence, in this study, for the first time, P(3HO)/bacterial cellulose composites have been developed. The addition of bacterial cellulose has resulted in properties that are highly desirable for medical applications including the development of biodegradable stents.
BACKGROUND: Both hydroxyapatites (HAp) and bacterial cellulose (BC) are excellent biomaterials. The former has outstanding osteoconductivity and bioactivity, while the latter has been proven to be a remarkably versatile biomaterial. By alkaline treatment, Ca ²⁺ activation, and biomimetic mineralization, the nanocomposites (CaDHCAp/BC) consisting of calcium‐deficient carbonate‐containing hydroxyapatite (CaDHCAp) in the three‐dimensional (3D) network of BC nanofibers were synthesized.
RESULTS: The CaDHCAp/BC nanocomposites obtained were characterized by inductively coupled plasma atomic emission spectroscopy (ICP‐AES), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X‐ray diffraction spectroscopy (XRD). The results indicated that alkaline treatment improved the apatite nucleation ability of BC, and the apatite crystals deposited along BC nanofibers were partially substituted with calcium carbonate and the uniform spherical apatite particles were composed of squama‐shaped nano‐sized apatite crystals. The crystallite sizes of apatite crystals are below 10 nm and the crystallinities are below 1%. The formation mechanism of CaDHCAp crystals along the BC fibers was described.
CONCLUSION: Alkaline treatment was introduced before the biomimetic mineralization process. Compared with the results without alkaline treatment, the mineralization efficiency was obviously improved. The nanocomposites obtained may have potential application as an orthopedic biomaterial. Copyright © 2008 Society of Chemical Industry
Biodegradable scaffolds have played an important role in a number of tissue engineering attempts over the past decade. The goal of this review article is to provide a brief overview of some of the important issues related to scaffolds fabricated from synthetic biodegradable polymers. Various types of such materials are available; some are commercialized and others are still in the laboratories. The properties of the most common of these polymers are discussed here. A variety of fabrication techniques were developed to fashion polymeric materials into porous scaffolds, and a selection of these is presented. The very important issue of scaffold architecture, including the topic of porosity and permeability, is discussed. Other areas such as cell growth on scaffolds, surface modification, scaffold mechanics, and the release of growths factors are also reviewed. A summary outlining the common themes in scaffold-related science that are found in the literature is presented. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res, 55, 141–150, 2001
Structural characteristics of microbial cellulose synthesized by two different methods have been compared using FT-IR and X-ray diffraction techniques. Cellulose synthesized by Acetobacter xylinum NQ-5 strain from agitated culture conditions is characterized by a lower I mass fraction than cellulose that was produced statically. Such a decrease was in good correlation with smaller crystallite sizes of microfibrils produced in agitated culture. Formation of characteristic cellulose spheres during agitation has been investigated by various electron and light microscopic methods. On this basis, a hypothetical mechanism of sphere formation and cell arrangement in the agitated culture has been proposed. During agitation, cells are stacked together in organized groups around the outer surface of the cellulose sphere.