Comprehensive collagen crosslinking comparison of microfluidic wet-extruded microfibers for bioactive surgical suture development.

Collagen microfiber-based constructs have garnered considerable attention for ligament, tendon, and other soft tissue repairs, yet with limited clinical translation due to strength, biocompatibility, scalable manufacturing, and other challenges. Crosslinking collagen fibers improves mechanical properties; however, questions remain regarding optimal crosslinking chemistries, biocompatibility, biodegradation, long-term stability, and potential for biotextile assemble at scale, limiting their clinical usefulness. Here, we assessed over 50 different crosslinking chemistries on microfluidic wet-extruded collagen microfibers made with clinically relevant collagen to optimize collagen fibers as a biotextile yarn for suture or other medical device manufacture. The endogenous collagen crosslinker, glyoxal, provides extraordinary fiber ultimate tensile strength near 300MPa, and Young's modulus of over 3GPa while retaining 50% of the initial load-bearing capacity through 6 months as hydrated. Glyoxal crosslinked collagen fibers further proved cytocompatible and biocompatible per ISO 10993-based testing, and further elicits a predominantly M2 macrophage response. Remarkably these strong collagen fibers are amenable to industrial braiding to form strong collagen fiber sutures. Collagen microfluidic wet extrusion with glyoxal crosslinking thus progress bioengineered, strong, and stable collagen microfibers significantly towards clinical use for potentially promoting efficient healing compared to existing suture materials. STATEMENT OF SIGNIFICANCE: Towards improving clinical outcomes for over 1 million ligament and tendon surgeries performed annually, we report an advanced microfluidic extrusion process for type I collagen microfiber manufacturing for biological suture and other biotextile manufacturing. This manuscript reports the most extensive wet-extruded collagen fiber crosslinking compendium published to date, providing a tremendous recourse to the field. Collagen fibers made with clinical-grade collagen and crosslinked with glyoxal, exhibit tensile strength and stability that surpasses all prior reports. This is the first report demonstrating that glyoxal, a native tissue crosslinker, has the extraordinary ability to produce strong, cytocompatible, and biocompatible collagen microfibers. These collagen microfibers are ideal for advanced research and clinical use as surgical suture or other tissue-engineered medical products for sports medicine, orthopedics, and other surgical indications.