Biopolyester / natural polymer blends for biomedical applications

Abstract

In this thesis, it is aimed to fabricate an antibiotic delivery system with optimal release kinetics that will overcome this problem. In recent years, fabrication of biocompatible electrospun nanofibers for drug delivery applications is the subject of increased interest, since they mimic the extracellular matrix, provide high surface area, and controlled drug release. In the present study, natural polymers (gelatin or both gelatin and chitosan) were blended with enzymatically synthesized biopolyester, poly(ω-pentadecalactone-co-ε-caprolactone) copolymer (PDL-CL), in order to obtain a synergetic effect. By the use of synthetic and natural polymers together, it was aimed to combine well-defined degradation and mechanical properties of a synthetic polymer with biocompatibility, cell adhesivity, and ability of site-specific delivery due to their functional groups of natural polymers. In this way, PDL-CL/gelatin and PDL-CL/gelatin/chitosan nanofibrous membranes were fabricated for controlled delivery of tetracycline hydrochloride (TCH) which is a commonly preferred antibiotic for treatment of skin infections resulted from a cut, burn or surgical operation. PDL-CL copolymer was synthesized by the catalysis of a home-made immobilized enzyme, Candida antarctica lipase B (CALB) immobilized onto rice husk ashes (RHA) via physical adsorption. Lipase-catalyzed copolymerization studies are limited and there is an increasing interest to improve material features by this way. Moreover, utilization of an enzymatically synthesized polymer rather than a polymer synthesized by organometallic catalysts in a formulation that will be used for a biomedical application may be advantageous, since the resulting product will be metal-free. Electrospinning of an enzymatically synthesized polymer is a challenging issue due to their low molecular weights, therefore studies that cover fabrication of electrospun nanofibrous drug delivery systems using an enzymatically synthesized polymer are limited in literature.