Smart biomaterials design for tissue engineering and regenerative medicine.
ABSTRACT As a prominent tool in regenerative medicine, tissue engineering (TE) has been an active field of scientific research for nearly three decades. Clinical application of TE technologies has been relatively restricted, however, owing in part to the limited number of biomaterials that are approved for human use. While many excellent biomaterials have been developed in recent years, their translation into clinical practice has been slow. As a consequence, many investigators still employ biodegradable polymers that were first approved for use in humans over 30 years ago. During normal development tissue morphogenesis is heavily influenced by the interaction of cells with the extracellular matrix (ECM). Yet simple polymers, while providing architectural support for neo-tissue development, do not adequately mimic the complex interactions between adult stem and progenitor cells and the ECM that promote functional tissue regeneration. Future advances in TE and regenerative medicine will depend on the development of "smart" biomaterials that actively participate in the formation of functional tissue. Clinical translation of these new classes of biomaterials will be supported by many of the same evaluation tools as those developed and described by Professor David F. Williams and colleagues over the past 30 years.
Article: Cell therapies for heart function recovery: focus on myocardial tissue engineering and nanotechnologies.[show abstract] [hide abstract]
ABSTRACT: Cell therapies have gained increasing interest and developed in several approaches related to the treatment of damaged myocardium. The results of multiple clinical trials have already been reported, almost exclusively involving the direct injection of stem cells. It has, however, been postulated that the efficiency of injected cells could possibly be hindered by the mechanical trauma due to the injection and their low survival in the hostile environment. It has indeed been demonstrated that cell mortality due to the injection approaches 90%. Major issues still need to be resolved and bed-to-bench followup is paramount to foster clinical implementations. The tissue engineering approach thus constitutes an attractive alternative since it provides the opportunity to deliver a large number of cells that are already organized in an extracellular matrix. Recent laboratory reports confirmed the interest of this approach and already encouraged a few groups to investigate it in clinical studies. We discuss current knowledge regarding engineered tissue for myocardial repair or replacement and in particular the recent implementation of nanotechnological approaches.Cardiology research and practice. 01/2012; 2012:971614.
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ABSTRACT: Tissue engineering has recommended the development of biomaterials for implantable porous scaffolds at the injured site, which temporarily acted as the supporting materials for ingrowths of the cells and degraded along with extra cellular matrix production, vascularization and tissue regeneration. Usually, three dimensional scaffolds play the most important role in the design of Tissue Engineering Construct that affects the cell fate process. Natural Polymer biomaterial such as Collagen, Keratin mimics the extra cellular matrix at the site of injury for regeneration of tissue. Collagen is one of the protein biomaterials and already prominently placed in the development of tissue engineering contructs.But due to poor environmental conditions, Collagen denatures into gelatin which lost triple helix conformation and also affects the cell fate process. Keratin is one of the fibrous proteins found in the extra cellular matrix, providing outer covering such as wool, hair feathers and nail and alternative to collagen biomaterials. The presence of high cysteine content in the keratin helps to immobilize the bioactive molecules for drug delivery application. The extracted keratin from horn meal is made into the macro porous scaffold by freeze drying method. The molecular weight of extracted keratin was determined by SDS.Poly acryl amide gel electrophoresis and was characterized by CD spectroscopy, FTIR. The scanning electron microscopy studies of macro porous Keratin scaffold confirms that the scaffold has interconnectivity heterogeneous pores that will help to bind with drugs or cells for design of drug delivery systems and tissue engineering constructs. INTRODUCTION The regeneration of tissues at the site of damage is really a challenging task in the field of Tissue Engineering 1 . The need of suitable biomaterials, which influence the formation of in vivo extra cellular matrix and support cellular proliferation for tissue regeneration, have motivated the word of sciences towards tissue engineering which in turn recommended the development of biomaterials for implantable macroporous scaffolds at the damaged site which temporarily act as the supporting materials for ingrowths of the cells and degrade along with in vivo extra cellular matrix production, vascularization and tissue regeneration 1 . Biocompatibility and biomaterial surfaces to favour cell attachment and enhance cell fate process are the fundamental requirements for development of biomaterial scaffold. The scaffold is a three dimensional substrate and it acts as a template for tissue regeneration. The ideal scaffolds should have an appropriate surface chemistry and microstructures to facilitate cellular attachment, proliferation and differentiation. In addition to that, the scaffolds should possess adequate mechanical strength and degradation rate without any undesirable by-products that should not cause any immunological effects. Generally, Biomaterials made from fibrous protein mimics the extra cellular matrix at the site of injury for regeneration of tissues 2,3 . Collagen is one of the most prominent protein based biomaterials and already ruled in the development of tissue engineering constructs with few limitations. Due to extreme conditions, Collagen denatures into gelatin which lost triple helix conformation. So, the collagen biomaterials needs cross linking whichINTERNATIONAL JOURNAL OF PHARMACEUTICAL AND CHEMICAL SCIENCES. 10/2012;
Article: Contribution of lysine-containing cationic domains to thermally-induced phase transition of elastin-like proteins and their sensitivity to different stimuli.[show abstract] [hide abstract]
ABSTRACT: A series of elastin-like proteins, SKGPG[V(VKG)(3)VKVPG](n)-(ELP1-90)WP (n = 1, 2, 3, and 4), were biosynthesized based on the hydrophobic and lysine linkage domains of tropoelastin. The formation of self-assembled hydrophobic aggregates was monitored in order to determine the influence of cationic segments on phase transition properties as well as the sensitivity to changes in salt and pH. The thermal transition profiles of the proteins fused with only one or two cationic blocks (n = 1 or 2) were similar to that of the counterpart ELP1-90. In contrast, diblock proteins that contain 3 and 4 cationic blocks displayed a triphasic profile and no transition, respectively. Upon increasing the salt concentration and pH, a stimulus-induced phase transition from a soluble conformation to an insoluble aggregate was observed. The effects of cationic segments on the stimuli sensitivity of cationic bimodal ELPs were interpreted in terms of their structural and molecular characteristics.BMB reports 01/2011; 44(1):22-7. · 1.72 Impact Factor