Comparative behaviour of electrospun nanofibers fabricated from acid and alkaline hydrolysed gelatin: towards corneal tissue engineering

Abstract

Gelatin is a hydrolysed form of collagen which is categorised as type A (acid hydrolysed) or type B (base hydrolysed), based on method of hydrolysis. In this work, we have studied the comparative properties of electrospun nanofibers of gelatin A (GA) and gelatin B (GB) prepared using a ternary solvent (glacial acetic acid/ethyl acetate/water). In addition, silk fibroin was used to improve the integrity and stability of gelatin nanofibrous sheets. Silk fibroin is known to serve as a potential implantable biomaterial because of its optimal mechanical stability, transparency, cell proliferation and tunable degradability. GA scaffold and silk permeated gelatin A nanofibrous scaffold (SFG) showed 50-70% of transparency comparable to that of adult rat and goat cornea. ATR-FTIR analysis showed the presence of native functional groups and bonds. Scanning electron microscope (SEM) micrographs revealed the porous nature of the scaffolds i.e., 48.08± 3.35 and 51.38 ± 3.72 for GA and GB, respectively. GB nanofibrous scaffolds got dissolved instantly in phosphate buffer solution (PBS), while GA scaffolds remained stable up to ∼ 11 h at 25˚C, however got degraded within 12 h when incubated at 37˚C. Furthermore, SFG scaffolds physically cross-linked with ethanol vapour displayed relatively improved stability when examined for at least 6 days at 37°C, minor weight loss when incubated in a lysozyme solution and facilitated the cellular proliferation significantly. Liquid retention capacity of the electrospun GA nanofibrous scaffolds was found to be nearly 800% from its original weight within 48 h. The electrospun nanofibrous scaffolds i.e., SFG facilitated ~72% of cellular proliferation compared to the control for SIRC [Statens Seruminstitut Rabbit Cornea] fibroblasts cells by 5th day of cell culture. Comparative outcomes reveal that the electrospun GA nanofibers possess significantly better integrity and noted stability in an aqueous environment compared to GB nanofibrous scaffold. Moreover, owing to the enhanced integrity and better stability the GA nanofibrous scaffold in combination with silk fibroin could be exploited in corneal tissue engineering applications where transparency plays an indispensable characteristic.