Preparation and Characterization of Natural/Synthetic Hybrid Scaffolds

Abstract

It has been recognized that tissue engineering offers an alternative technique to whole organ and tissue transplantation for diseased, failed or malfunctioned organs. To reconstruct new tissues, cells which are harvested and dissociated from the donor tissue including nerve, liver, pancreas, cartilage, and bone, and scaffold substrates which cells are attached and cultured resulting in the implantation at the desired site of the functioning tissue is needed. Recently, the family of poly(△-hydroxy acid)s such as polyglycolide (PGA), polylactide (PLA) and its copolymer like poly(lactideco-glycolide) (PLGA) which are among the few synthetic polymers approved for human clinical use by FDA are extensively used or tested for the scaffold materials as a bioerodible material due to good biocompatibility, controllable biodegradability, and relatively good processability.’ These polymers degrade by nonspecific hydrolytic scission of their ester bonds. The hydrolysis of PLA yields lactic acid which is a normal byproduct of anaerobic metabolism in human body and is corporated in the tricarboxylicacid (TCA) cycle to be finally excreted by the body as carbon dioxide and water. PGA biodegrades by a combination of hydrolytic scission and enzymatic (esterase) action producing glycolic acid which can either enter the TCA cycle or be excreted in urine and be eliminated as carbon dioxide and water. The degradation time of PLGA can be controlled from weeks to over a year by varying the ratio of monomers and the processing conditions. It might be a suitable biomaterial for use in tissue engineered repair systems in which cells are implanted within PLGA films or scaffolds and in drug delivery systems in which drugs are loaded within PLGA microspheres.