Fabrication and characterization of Eri silk braided anterior cruciate ligament (ACL)

Purpose Anterior cruciate ligament (ACL) rupture is a common sports-related injury. Due to the limited regenerative capacity of the ACL, surgical repair using autografts and allografts is typically performed. In this context, Eri silk-based braided scaffolds for ACL reconstruction were fabricated using a circular braiding machine. Furthermore, this study aims to value added on ACL structure with the blended natural extract coating with of Tridax procumbens and chitosan to synergistically enhance wound healing and antibacterial activity. Design/methodology/approach Two braid types such as 3 and 6 plies were developed in three different configurations such as flat, round and diamond. To enhance the antimicrobial properties of the braided ACL structures, surface coatings were applied using blends of Tridax procumbens extract and chitosan. Findings The tensile strength and knot strength were found to be highest in the 6-ply round and diamond braided samples. Coating effectiveness was confirmed through Fourier transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) analysis. Five different blend ratios of Tridax procumbens and chitosan (1:1, 1:2, 2:1, 1:3 and 3:1) were used for coating, in addition to two control samples − one coated with raw chitosan and another with ethanol. Forty-two samples were developed for optimization studies. Antimicrobial testing revealed that the 1:2 Tridax procumbens:chitosan ratio exhibited the highest activity against Pseudomonas aeruginosa. The 1:3 Tridax procumbens:chitosan ratio showed superior antimicrobial effectiveness for all other microbial strains tested. The 1:3 coated 6-ply flat braided Eri silk sample demonstrated the highest overall antimicrobial activity among all the variants. Blood compatibility tests confirmed that all braided composite coatings did not induce significant adverse effects on blood components. Research limitations/implications Notably, the 1:3 Tridax procumbens: chitosan-coated sample exhibited significantly enhanced anti-inflammatory activity. Cytotoxicity assays on L929 fibroblast cell lines indicated slight to mild cytotoxicity after 24 h of exposure. Wound healing studies reported that the braided silk samples achieved up to 77% wound closure, confirming their potential for biomedical applications. Originality/value The purpose of this study is to enhance the natural extract coating on textile materials for the manufacture of artificial ligaments. To the best of the authors’ knowledge, this research work is the first of its kind to produce the Eri silk-based scaffolds coated with plant extract and biopolymer of Tridax procumbens and chitosan, offering a novel approach toward obtaining antimicrobial, anti-inflammatory and wound healing properties along with requisite tensile characteristic. The study paves the new direction for developing multifunctional, bio-active textile structured ACL grafts.