The Effect of Lignin Concentration on the Morphology and Structure of Silk Fibroin Nanofibers

Introduction and Objectives: With the rapid advancement of nanotechnology and the enhanced properties of materials at the nanoscale, electrospinning has emerged as a promising technique for restoring the functionality of damaged tissues due to its porous structure, which facilitates oxygen and gas permeability. This study aims to investigate the effect of lignin concentration on the morphology and structure of silk fibroin nanofibers to achieve uniform fibers suitable for biomedical applications.Materials and Methods: Silk fibroin was first extracted from silkworm cocoons and blended with lignin at ratios ranging from 5:1 to 7:1. Nanofibers were then fabricated using electrospinning at three voltage levels: 20, 25, and 30 kV. To assess the successful extraction of fibroin and the fabrication of fibers, various characterization techniques were employed. Initially, scanning electron microscopy was used to analyze the morphological characteristics, followed by contact angle measurements.Results: The findings indicated that both pure silk fibroin fibers and silk fibroin-lignin composite fibers fabricated at 20 kV with lignin ratios of 5:1, 6:1, and 7:1 exhibited uniform structures, with average diameters of 241.44 ± 37 nm, 309.10 ± 11 nm, 164.05 ± 74 nm, and 181.38 ± 58 nm, respectively. Moreover, contact angle analysis revealed that the water contact angle of pure silk fibroin (49 ± 5°) increased to 63 ± 4°, 66 ± 2°, and 71 ± 6° for composite fibers with lignin ratios of 5:1, 6:1, and 7:1, respectively.Conclusion: Given that the contact angle values fall within the range of 55–75° and the nanofibers exhibit a uniform structure, silk fibroin-lignin composite nanofibers provide a favorable surface for cell adhesion and proliferation, making them promising candidates for biomedical applications.