A low-cost method for developing a β-sheet packed silk fibroin powder for medical application in LMICs

Abstract

Background: FDA clinically approved silk for biomedical products in 2013 leading to its increased use. The silk comprises regenerated silk fibroin (SF) rich in β-sheet and with no traces of silk sericin. Removal of silk sericin(degumming) helps to convert silk I into silk II (β-sheet-rich SF). β-sheets provide silk with biocompatibility, biodegradability, and mechanical properties. Degummed SF is stored in different formats; SF-fibre, SF-solvent, SF-aqueous, and SF powder. Although SF-aqueous is commonly used, it poses challenges in LMICs because of its short shelf life posing the need for new batches. Furthermore, LMICs face limited access to silk solvent alternatives. Aim: To develop a low-cost method for producing a β-sheet packed silk fibroin powder for medical application in LMICs Results: Successful SF dissolution occurred using cheaper solvent alternatives and optimising done for appropriate process. 1 wt% SF dissolution in formic acid: LiCl (FL) occurred at 60oC after 45min while with formic acid: CaCl2 (FC) at 60oC after 55min. UV-Vis analysis showed an increase in SF nanoparticles from e = 1.426 to 2.652 after dialysis indicating that solvent removal purified the solution. FTIR showed the presence of b-sheets in the SF powder at amide I, amide II, and twin amide III bands indicating the presence of silk II.