Electrospinning of core shell nanofibers using amine modified sericins

Abstract

Abstract In this study as a renewable resorce, silk sericin (SS), a protein surrounding fibroin fibers in silk, was chemically modified with various amines (e.g., methylamine, butylamine) to improve its functional properties. These modifications, which included nucleophilic substitution reactions, improved its thermal stability, mechanical strength, and biological activity by substituting primary amine groups in place of hydroxyl ions in the structure. Modified SS (M-SS) was then used to produce nanofiber membranes via coaxial electrospinning. In this process, polyvinyl alcohol (PVA) served as the hydrophilic and SS/M-SS carrier polymer to delay biodegradation, while hydrophobic polylactic acid (PLA) and polycaprolactone (PCL) formed the shell to enhance mechanical strength and provide minimum adhesion to wounded tissues. This technique enabled the stable fabrication of core–shell nanofibers containing SS/M-SS, which are typically difficult to electrospin alone. Among the M-SS variants, methylamine-modified sericin (SMAT) yielded nanofibers with the highest tensile strength (0.673 MPa) and 6.44% elongation. The highest thermal resistance was observed in methylamine (SNF7) and butylamine (SNF9) modifications, with SNF7 showing 5% mass loss at 250 °C. The lowest resistance was seen in benzylamine-modified fibers (SNF11) at 220 °C. SNF9 also exhibited the highest cell viability, indicating its potential for biomedical applications.