Catalin Zaharia

• Full Professor
• Head of Department at National University of Science and Technology Politehnica Bucharest

Nanocomposite hydrogels are gaining significant attention for biomedical applications in soft tissue engineering due to the increasing demand for highly flexible and durable soft polymer materials. This research paper focused on investigating and optimizing a procedure for the development of novel nanocomposite hydrogels based on poly(2-hydroxyethy...

By the late 1970s, plastics had emerged as the most widely used materials globally. The discovery, development, and processing of diverse polymeric materials have profoundly shaped modern life and driven the expansion of numerous industries. Given the widespread interest in the utilization of these materials, it has become increasingly imperative t...

The development of functional and sustainable materials for additive manufacturing is a rapidly expanding area of interest. In this context, composite blends of chitosan—including commercial low and medium molecular weight variants, as well as laboratory-extracted chitosan from shrimp head and shell waste—and polylactic acid (PLA) were prepared usi...

Structurally defined, protein‐grafted nanoparticles are widely used in various biomedical applications, particularly as intelligent nanocarriers for drug delivery. The integration of synthetic polymers with natural proteins such as silk sericin enhances the functionality and stability of these nanocarriers, making them suitable for targeted and con...

Cardiovascular diseases, a leading cause of global mortality, are driving increased demand for artificial blood vessels for surgical repair. This study discloses the fabrication of three-dimensional (3D)-printed small blood vessels as tissue-engineered grafts. Large-diameter artery and vein grafts are readily available in the market, but small-diam...

Purpose The development of new advanced materials, such as photopolymerizable resins for use in stereolithography (SLA) and Ti6Al4V manufacture via selective laser melting (SLM) processes, have gained significant attention in recent years. Their accuracy, multi-material capability and application in novel fields, such as implantology, biomedical, a...

Advancements in materials science and 3D printing technologies have opened up new avenues for developing low-cost robotic grippers with high-performance capabilities, making them suitable for various biomechatronic applications. In this research, it has been explored the utilization of high-performance polymer materials, such as Polyetherketoneketo...

This paper reports the preparation and characterization of thermosensitive poly(N-isopropylacrylamide) (PNIPAM)/magnetite nanoparticles in various conditions. The nanoprecipitation conditions address the impact of the temperature on PNIPAM/magnetite nanoparticle features due to the thermosensitive character of PNIPAM. Hybrid nanoparticles with desi...

The aim of this study was to obtain biocomposites consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), bacterial cellulose (BC) and α-tocopherol by a melt processing technique for potential use in biomedical applications. The melt processing and roughness of biocomposites were evaluated and compared to sample without BC. The degradati...

In the last years, additive manufacturing technologies have been developed, especially direct metal laser sintering, and used in the dental and medical implant domains. Cardiovascular stents have evolved from bioinert, bare metal cages to biomimetic devices that promote tissue regeneration or healing. In this paper, comparisons concerning mechanica...

Nowadays, Gram-negative bacteria (GNB) are among the most significant public health and environment concerns in the world due to their high resistance to antibiotics [...]

Organ-on-chips (OOCs) are microfluidic devices used for creating physiological organ biomimetic systems. OOC technology brings numerous advantages in the current landscape of preclinical models, capable of recapitulating the multicellular assemblage, tissue–tissue interaction, and replicating numerous human pathologies. Moreover, in cancer research...

Due to their remarkable structures and properties, three-dimensional hydrogels and nanostructured clay particles have been extensively studied and have shown a high potential for tissue engineering as solutions for tissue defects. In this study, four types of 2-hydroxyethyl methacrylate/2-acrylamido-2-methylpropane sulfonic acid/montmorillonite (HE...

The present work reported the preparation of biocomposites based on poly(3-hydroxybutyrate) (PHB), plasticizer, and bacterial cellulose (BC) by melt processing and their testing by means of thermal properties (DSC), water absorption, and in vitro degradation. The surface of the biocomposites was analyzed via atomic force microscopy (AFM). In vitro...

The possibility of using EPR spectroscopy to monitor the current concentration of polyaniline and control the kinetics of aniline polymerization is shown. Kinetic measurements were carried out for various temperatures, initial concentrations of reagents. Autocatalysis was detected in all cases. It was shown that the order of polyaniline-catalyzed o...

Colorectal cancer (CRC), is the second cause of cancer-related deaths worldwide is one of the most prevalent types of cancers. Conventional treatment continues to rely on surgery, chemotherapy, and radiotherapy, but for advanced cases, adjuvant chemotherapy remains the main approach for improving surgical outcomes and lower the disease recurrence p...

In this paper, Bombyx mori silk sericin nanocarriers with a very low size range were obtained by nanoprecipitation. Sericin nanoparticles were loaded with doxorubicin, and they were considered a promising tool for breast cancer therapy. The chemistry, structure, morphology, and size distribution of nanocarriers were investigated by Fourier transfor...

5-fluorouracil (5-FU) remains the gold standard of treatment for colorectal cancer, but its poor bioavailability and high systemic toxicity highlight the urgent need for the development of novel delivery strategies to increase the efficacy of 5-FU treatment. The present study is aimed to design and validate a PEGylated Silk Fibroin Nanocarrier (SF/...

Globally, colorectal cancer (CRC) ranks as one of the most prevalent types of cancers at the moment, being the second cause of cancer-related deaths. The CRC chemotherapy backbone is represented by 5-fluorouracil, oxaliplatin, irinotecan, and their combinations, but their administration presents several serious disadvantages, such as poor bioavaila...

The present study investigated the possibility of obtaining 3D printed composite constructs using biomaterial-based nanocomposite inks. The biopolymeric matrix consisted of methacrylated gelatin (GelMA). Several types of nanoclay were added as the inorganic component. Our aim was to investigate the influence of clay type on the rheological behavior...

Dressing biomaterials play a key role in wound management keeping a moisture medium and protecting against external factors. Natural and synthetic materials could be used as dressings where chitosan and bacterial cellulose is one of the most important solutions. These biopolymers have been used for wound dressing based on their non-toxic, biodegrad...

The aim of this research consists in the development of drug delivery formulations based on silk fibroin and polyethylene glycol nanoparticles. The obtained nanoparticles were characterized by FTIR-ATR and RAMAN. The morphological investigation and size distribution profile of the nanoparticles were performed by scanning electron microscopy (SEM) a...

The past few years have witnessed major developments in nanotechnology with great potential in powering new therapeutic tools for cancer management. Our goal in this study was to develop a biocompatible nanoshuttle for the efficient delivery of 5FU in colorectal cancer patients. Silk fibroin/Poly(ethylene glycol) nanoparticles (SF/PEG NPs) were obt...

Micro-computed tomography (µ-CT) is an X-ray technique with (sub)micron resolution, [...]

Nanocomposite materials based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) and modified mineral clay layered double hydroxides (LDH-SDS) were explored as novel nanostructured materials for potential tissue engineering applications. The mineral clay inorganic phase was modified with an anionic long-chain structure of carbon atoms, such as...

This paper reports the impact of the magnetic field on 3T3-E1 preosteoblasts within silk-fibroin scaffolds decorated with magnetic nanoparticles. Scaffolds were prepared from silk fibroin and poly(2-hydroxyethyl methacrylate) template in which magnetite nanoparticles were embedded. The presence of the magnetite specific peaks within scaffolds compo...

Bone regeneration is a claim challenge in addressing bone defects with large tissue deficits, that involves bone grafts to support the activity. In vitro biocompatibility of the bacterial cellulose-modified polyhydroxyalkanoates (PHB/BC) scaffolds and its osteogenic potential in critical-size mouse calvaria defects had been investigated. Bone promo...

This paper reports the synthesis and complex characterization of novel polymeric networks based on the crosslinking of Bombyx mori silk fibroin via poly(N-isopropylacrylamide) bridges generated by an ammonium cerium nitrate redox system. The research study gives an understanding of the polymerization mechanism in terms of the generation of radical...

This paper reports the synthesis and complex characterization of nanocomposite hydrogels based on polyacrylamide and functionalized magnetite nanoparticles. Magnetic nanoparticles were functionalized with double bonds by 3-trimethoxysilyl propyl methacrylate. Nanocomposite hydrogels were prepared by radical polymerization of acrylamide monomer and...

This study aims to provide an overview of the main polyhydroxyalkanoates (PHAs) used in medical applications. In this review, it has been demonstrated that the properties of PHAs can be controlled both by varying the concentration of units in the copolymer and the substrate for PHA production. Another way of controlling the mechanical properties of...

Aiming to address the issue of poor bioavailability of most anti-tumor medicines against colorectal cancer, we developed a targeted anticancer nanocarrier using biocarriers able to both bind and easily release their load in a controlled manner. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) carriers were obtained via the emulsification-diffusion meth...

The paper focuses on the obtaining of novel nanocomposite hydrogels based on polyacrylamide and layered double hydroxides (LDHs) modified with double bonds. The modification of LDH clay was investigated by FTIR, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses. Mechanical properties of the nanocomposite hydrogels were emp...

Nanocomposite materials have attracted a high interest for biomedical applications because their special properties related with structure and composition. In this paper we synthesized novel hydrogel nanocomposite materials special designed for hard tissue engineering. The nanocomposite materials are able to promote hydroxyapatite formation by alte...

Ballistic gelatin as simulant of the human body and organs is a support in forensics. After having obtained very good results for a new gelatin-based composite in terms of physicochemical and rheological properties, this study focused on this material's mechanical behavior during stabbing and shooting versus bovine and porcine organs and standard b...

The aim of this study was to address one of the major challenges of the actual era of nanomedicine namely, the bioavailability of poorly water soluble drugs such as Silymarin. We developed new, biodegradable, and biocompatible nanosized shuttles for Silymarin targeted delivery in colon-cancer cells. The design of these 100 nm sized carrier nanopart...

The paper is focused on designing a novel silk fibroin-magnetite biomaterial scaffold for wounds healing in terms of: synthesis, physico-chemical and morphological characterization and in vitro biological behaviour assessment. Magnetic scaffolds were prepared from silk fibroin solutions and magnetic nanoparticles with various concentrations by solv...

Direct Metal Laser Sintering process is modern technology and is used in different industries, inclusive in medicine industry. The purpose of this study was to obtain sintered compacts of Co-Cr powder doped with ZrO2 in order to improve the bioactivity of the implants and the behavior in vitro after immersion in simulated biological fluid (SBF) for...

Ballistic gelatin is the simulant of the human body during field tests in forensics and other related fields, due to its physical and mechanical similarities to human trunk and organs. Since the ballistic gelatin used in present has important issues to overcome, an alternative approach is the use of gelatin-polymer composites, where a key factor is...

Hemp fibers (HF) were treated with γ-Aminopropyltriethoxysilane, γ-Glycidoxypropyltrimethoxysilane, γ-Methacryloxypropyltrimethoxysilane (MPS) and potassium permanganate (KP), without alkaline pretreatment, to improve the mechanical properties of polypropylene (PP)/HF composites for automotive parts. MPS and KP treatments were the most efficient in...

This research study is focused on the synthesis and characterization of novel biocomposites based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and modified layered double hydroxides for tissue engineering applications. The biocomposites were obtained by solvent casting technique from polymer solutions containing dispersed clay particles. After p...

Fluorinated epoxy resins (FERs) were extensively studied for applications in electronic packaging, optical waveguides, and antifouling coatings. This research focuses on the synthesis and characterization of FER following a polycondensation reaction between fluorinated bisphenol and epichlorohydrin. Cure reaction was monitored using dispersive Rama...

The present work reports on the biocompatibility of poly (3-hydroxybutyrate) and poly (3-hydroxybutyrate-co-3-hydroxyvalerate) loaded with bacterial cellulose and microcrystalline cellulose via melt processing. Biocompatibility was tested by physico-chemical and in vitro methods. Physico-chemical tests of biocomposites, such as reducing substances,...

The purpose of this study was to determine the bioactivity of Co-Cr disks manufacturing by Direct Metal Laser Sintering (DMLS) process. The Co-Cr samples realized by DMLS process were coated with hydroxyapatite (HA) obtained by sol-gel method to improve the bioactivity of the implants. The Co-Cr samples coated with hydroxyapatite were immersed in s...

Biocompatible synthetic polymers play an important role in medical applications, such as prosthetic devices (drains, catheters, hip, knees, etc.) employed at the present time by millions of patients. Polymers used as prosthetic devices include polyurethanes, silicone rubbers, teflon and vinyl polymers or copolymers. The possibility of utilization o...

The purpose of this study was to obtain Co-Cr sintered compacts doped with hydroxyapatite (HA) in order to improve the bioactivity of implants and the in vitro behavior after an immersion in simulated biological fluid (SBF 1x) for 7 days. Co-Cr powder (ST2724G) was used to realize four compacts doped with 5wt% HA, 10wt% HA, 15wt% HA and 20wt%HA. Th...

Porous chitosan/graphene oxide (CHT/GO) biocomposites with 0.5, 1, 2, and 3 wt% GO were prepared by freeze-drying method. The biocomposites were characterized regarding structural, morphological, and thermal properties, degradation, and swelling responses. Raman spectroscopy and scanning electron microscopy (SEM) results indicated good GO dispersio...

The quality of life of patients with chronic wounds can be extremely poor and, therefore, over the past decades, great efforts have been made to develop efficient strategies to improve the healing process and the social impact associated with these conditions. Cell based therapy, as a modern tissue engineering strategy, involves the design of 3D ce...

The paper focuses on the synthesis and evaluation of biomineralization potential of composite materials based on bacterial cellulose and synthetic acrylic polymers with negative groups attached. The composite materials were obtained by grafting the monomers carrying negative groups onto the surface of bacterial cellulose. These grafted membranes we...

The paper focuses on the development of composite materials based on bacterial cellulose and poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV). Natural composites were obtained from bacterial cellulose membranes and chloroform copolyester solutions (various mass ratios). The composite membranes were characterized by FT-IR spectroscopy, X-ray di...

The research study focuses on the preparation and characterization of composite materials based on bacterial cellulose and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) as biodegradable scaffolds for tissue engineering applications. Bacterial cellulose/polyhydroxyalkanoates composite membranes were prepared from BC membranes and PHBHV chloroform sol...

This paper focuses on the development of silkworm fibroin/polyacrylamide/carboxylated MWCNTs hydrogels as biomimetic materials to support the mineralization process. Hydrogels were obtained by free radical polymerization of acrylamide and methylenebisacrylamide in silk fibroin solutions containing dispersed carboxylated multiwall carbon nanotubes w...

The present work reports on the synthesis and biomineralization capacity of hydrogel networks composed of Bombyx mori silk fibroin, polyacrylamide and carboxylated multiwall carbon nanotubes soaked in simulated body fluid. Hydrogels were fabricated by the polymerization of acrylamide and N,N’ methylenebisacrylamide in silk fibroin solution containi...

The paper reports on the synthesis and characterization of domesticated Bombyx mori silk fibroin (SF) micro- and nanoparticles used for controlled drug delivery systems. SF micro- and nanoparticles were obtained by precipitation in different organic solvents. The fibroin samples were characterized by FTIR-ATR spectroscopy and SEM analysis. The use...

Currently, the active materials used for the fabrication of solar cells are mainly inorganic. Materials such as silicon (Si), gallium-arsenide (GaAs), cadmium-telluride (CdTe), and cadmium-indium-selenide (CIS). Nevertheless, the large production cost for the silicon solar cells is one of the major drawback in this field. This chapter is dedicated...

Currently, the active materials used for the fabrication of solar cells are mainly inorganic. Materials such as silicon (Si), gallium-arsenide (GaAs), cadmium-telluride (CdTe), and cadmium-indium-selenide (CIS). Nevertheless, the large production cost for the silicon solar cells is one of the major drawback in this field. This chapter is dedicated...

This paper reports the mineralization ability of semi-interpenetrating networks composed of regenerated silk fibroin and polyacrylamide hydrogels soaked in simulated body fluid (SBF1x). Hydrogels were prepared by polymerization of acrylamide and N,N′-methylenebisacrylamide in silk fibroin solution with a redox pair as initiator. The incorporation o...

Silks are fibrous proteins with remarkable mechanical properties produced in fiber form by silkworms and spiders. Silk fibers in the form of sutures have been used for centuries. The unique mechanical properties, controlled biodegradability, haemostatic properties of these fibres provided important clinical repair options for many applications. Dur...

This paper reports the mineralization ability of semi-interpenetrating networks composed of regenerated silk fibroin and polyacrylamide hydrogels soaked in simulated body fluid (SBF1x). Hydrogels were prepared by polymerization of acrylamide and N,N′-methylenebisacrylamide in silk fibroin solution with a redox pair as initiator. The incorporation o...

The structure and properties of the bio-hybrids based on starch and PVOH obtained with MMT conditioned before melt processing into a good plasticizer depends on the conditioning sequence characteristics. A small influence on the silicate morphology can be a sign that the silicate was only hydrated by water and it is not yet dispersed into water. Th...

The main characteristics of pressure sensitive adhesives are: peel, shear and tensile strength. This paperwork presents the shear tests and related phenomena of pressure sensitive adhesives based on polychloroprene rubber using both metallic and polymeric substrates. The influence of the main parameters which control the shear strength of the adhes...

Solutions of polyacrylamide modified by Mannich reaction and quaternized have various applications: purification of waste and potable water, decrease of friction coefficient in fluids transport, textile industry, food industry, paper industry etc. These solutions show instability characterized by the variation of viscosity in time, fact that influe...

This paper reports the mineralization ability of 2-hydroxyethyl methacrylate (HEMA) and 2-methacryloylamido glutamic acid (MAGA) based copolymers incubated in synthetic fluids. MAGA monomer was obtained by organic synthesis and next p(HEMA-co-MAGA) copolymers with different compositions were prepared by bulk radical polymerization using benzoyle pe...

Multiwall carbon nanotubes (CNTs) have been brominated by photochemical bromine addition. XPS analysis has been used to determine the amount of bromine reacted. By measuring the concentrations of the co-initiator and the monomer, multiwall carbon nanotubes functionalized with hydrosoluble polymers—polyhydroxyethylacrylate (PHEA) and polyacrylamide...

Preparation of polymeric micro- and nanoparticles has significantly become an effective approach for achieving efficient drug targeting to tumour tissues. A promising solution could be the use of a radio-opaque polymeric system carrying iodine groups. In this context, radio-opaque polymeric microparticles based on methyl methacrylate (MMA) and an 2...

The paper presents the effects of the miscibility and of the micro-structure on the surface defects of some bio-hybrides based on starch, polyvinyl alcohol (PVOH) and multilayered silicates. At macroscopic level (100μ) the studied starch bio-hybrids seem to be compact materials. If these materials are analysed at a microscopic level (10 μ) dependin...

Abstract: The surface property of a biomaterial is known to affect its cell compatibility considerably, which is of particular importance for a medical implant, because the surface contacts directly with the host tissue. A suitable morphology on the implant’s surface serves to guide cell adhesion, migration, and proliferation, and is a key to succe...

Most of the Romanian treatment stations use surface waters to obtain potable water. Suspensions elimination is achieved though coagulation with aluminium sulphate or with aluminium polyhydroxychloride. These chemical reagents contaminate the potable water with aluminium ions, which may lead to different diseases of the organism. This paper focuses...

Natural fibrous polymers were chemically modified to mimic the behaviour of bone proteins responsible for mineralization. In this respect, itaconic acid (IA) and 2-hydroxyethyl methacrylate (HEMA) were grafted onto cellulose and fibroin from natural silk by two initiating systems. The resulted materials were incubated in synthetic body fluid and an...

This paper deals with the synthesis and characterization of new phtalocyanine based chromophores and new electrolyte for the fabrication of dye-sensitized solar cells (DSSCs) and hybrid dye-sensitized solar cells.The new phtalocyanines-based chromophores contain a different number of pending carboxy groups. The classic electrolyte was replaced by p...

The determination of energetic characteristics of six types of poplar clones was achieved, four developed by Alasia New Clones -Italy, (AF-2, AF-6, AF-8, Monviso) and two by ICAS -Romania (Turcoaia, Sacrau-79); they were cultivated for different pedoclimatic conditions in Romania. The plant survival rate and biomass production rate were analyzed in...

The copolymerization reaction between bisphenol A glycerolate dimethacrylate (BisGMA) and urethane dimethacrylate (UDMA) monomers was studied and the monomer reactivity ratios were determined on the base of the FTIR data obtained at different times of reaction. Both Fineman-Ross and copolymer composition equations were used. Also ProCop computation...

The behaviour of some microstructured polymers obtained under dynamic vulcanization conditions in a pilot reactor containing a mixture of EPDM rubber and high density polyethylene (HDPE) at various elastomer/plastic polymer weight ratios in the presence of sulphur (system I) and peroxides (system II) as cross-linking agents was studied. We correlat...