Multifunctional silk fibroin – Poly(L-lactic acid) porous nanofibers: Designing adjustable nanopores to control composite properties and biological responses

Nano-scale renewable porous materials have a wide range of applications in the biomedical field such as tissue engineering and biosensors due to their high biocompatibility and large surface area. In this study, a composite of silk fibroin and poly(L-lactic acid) was electrospun together to form a porous nanofiber biomaterial with 11 blending ratios to tune the porosity of the single fibers (19.3–49%). This is highly advantageous as porous fibers effectively promoted cell attachment and proliferation while also manipulating cell growth. The protein-polymer molecular interactions, structures and crystal contents, as well as the melting and glass transition behaviors of the composites were determined. Results reveal that varying silk fibroin content can directly tune the nanopore structure of each individual fiber. The composite nanofibers have a much higher thermal stability when compared to the pure silk or PLA nanofibers. Besides, as the SF concentration increased from 0% to 100%, the hydrophilicity of the electrospun composite fibers increased (contact angle decreased from 135° to 103°), and the enzymatic degradation residues also increased from 20% to 95%. This study provides a unique method for tuning nano-fabrication properties of electrospun protein-polymer fibers that can be widely useful in the fields of biomedicine and sustainable materials.