Cellulose Formate-Based Surgical Sutures With Tunable Absorbability and Enhanced Biocompatibility

Cellulose, as an abundant, renewable, and biocompatible material, is an ideal candidate for suture preparation. Yet, traditional cellulose sutures are non-absorbable because humans lack cellulase. Herein, cellulose-based threads were fabricated using cellulose formate (CF) and collagen (optimal weight ratio 1:1) with surface modification by poly(vinyl alcohol) (PVA). By incorporating collagen, the strength and toughness of the CF threads were enhanced to match commercial collagen sutures. Moreover, during physiological degradation, a small amount of released formic acid led to the conversion of 11.6% CF to glucose within 56 days, and glucose can be absorbed and utilized by the human body. This finding demonstrates its remarkable degradability and absorbability in vivo. Meanwhile, this thread offers tunable absorbability (in vitro strength loss > 50% within 21-49 days, by adjusting the polymerization degree and substitution degree of CF), aligning with the definition of absorbable sutures and matching the actual healing time of most wounds. Compared to absorbable collagen sutures, this novel CF-based thread exhibits superior antibacterial properties and comparable biocompatibility with cells and blood. Besides, it causes minimal inflammatory responses and promotes faster wound healing in vivo experiments. Therefore, this green cellulose-based thread shows great potential as an absorbable suture for advanced surgical applications.