Preparation of electrospun core-sheath nanofibers from poly(lactic acid)-collagen polymers and their biomedical applications

Abstract

Biomaterials are applied to living organisms and used as biomedical appliances to accomplish, enhance, or substitute particular natural functions. Completely hydrophobic or hydrophilic biomaterials are not suitable to be applied to cell growth. Poly(lactic acid) (PLA) is a biodegradable and bioresorbable synthetic polymer that is already in use in many commercial biomedical devices. In this study, commercial PLA was modified by grafting vinyl acetate (VAc) onto it using lithium tetrahydridoaluminate (LiAlH 4 ) or benzoyl peroxide (BPO) to increase the hydrophilic moiety. Resultant materials were characterized by FT-IR, 1 H-NMR, and 13 C-NMR, and hereafter the mechanism of the grafting processes was proposed. The materials were subjected to thermal analysis and X-ray diffraction studies for further characterization. Biocompatible and biodegradable polymers gelatins, a derivative of collagen and collagen, are used in biomedical applications. Additionally, electrospun nanofibrous scaffolds possess biomimic structures and have promising applications in tissue regeneration, especially for wound healing purposes. Electrospun nanofibrous scaffolds from the hydrophobic PLA, and hydrophilic gelatin blend solutions using Tween 80 were prepared. Solution properties such as conductivity, and viscosity of blended solutions were investigated, and the scaffolds were analyzed using FESEM. Moreover, core-sheath bi-polymeric scaffolds have been substantiated as promising materials centered on the requirements of scaffolds of component materials in which one polymer is covered (core) with another polymer. This work was also employed to prepare core-sheath scaffolds by using gelatin or collagen as core material and PLA or vinyl acetate grafted on PLA as sheath material to get the utmost properties of the polymers. Acid soluble collagen (ASC) was extracted from waste Tilapia fish skin. Amino acid profile of ASC revealed its triple helix structure whereas SDS-PAGE confirmed the existence of α1 (130 kDa), α2 (120 kDa) cross linked with a β (280 kDa) chain. Morphology of the scaffolds was determined by the FESEM. All the scaffolds were characterized further by FT-IR, TGA, DSC, and XRD. Cytotoxicity of all scaffolds were measured as well prior to in vivo application and cytotoxicity was not observed on Vero cell line. Water contact angle measurement of the scaffolds revealed that bi-polymeric scaffolds were more wettable than the single polymeric scaffold of PLA or grafted PLA. Scaffolds were applied to the surgically produced wounding of skin in a rat model followed by histological assay to observe their improved properties towards wound healing processes. Relative wound size reduction as well as healing were observed using bi-polymeric scaffolds rather than the use of a single polymeric scaffold of PLA or Grafted PLA. Histological assay also supported the bi-polymeric scaffolds as encouraging materials for tissue regeneration.