Multiaxial filament winding of biopolymer microfibers with a collagen resin binder for orthobiologic medical device biomanufacturing.

Abstract

Multiaxial filament winding is an additive manufacturing technique used extensively in large industrial and military manufacturing yet unexplored for biomedical uses. This study adapts filament winding to biomanufacture scalable, strong, three-dimensional microfiber (3DMF) medical device implants for potential orthopedic applications. Polylactide microfiber filaments were wound through a collagen 'resin' bath to create organized, stable orthobiologic implants, which are sized for common ligament (e.g. anterior cruciate ligament) and tendon (e.g. rotator cuff) injuries and can be manufactured at industrial scale using a small footprint, economical, high-output benchtop system. Ethylene oxide or electron beam sterilized 3DMF samples were analyzed by scanning electron microscopy (SEM), underwent ASTM1635-based degradation testing, tensile testing, ISO 10993-based cytocompatibility, and biocompatibility testing, quantified for human platelet-rich plasma (PRP) absorption kinetics, and examined for adhesion of bioceramics and lyophilized collagen after coating. 3DMF implants had consistent fiber size and high alignment by SEM. Negligible mass and strength loss were noted over 4 months in culture. 3DMF implants initially exceeded 1000 N hydrated tensile strength and retained over 70% strength through 4 months in culture, significantly stronger than conventionally produced implants made by fused fiber deposition 3D printing. 3DMF implants absorbed over 3xtheir weight in PRP within 5 min, were cytocompatible and biocompatible in vivo in rabbits, and could readily bind tricalcium phosphate and calcium carbonate coatings discretely on implant ends for further orthobiologic material functionalization. The additive manufacturing process further enabled engineering implants with suture-shuttling passages for facile arthroscopic surgical delivery. This accessible, facile, economical, and rapid microfiber manufacturing platform presents a new method to engineer high-strength, flexible, low-cost, bio-based implants for orthopedic and extended medical device applications.