A universal multi-platform 3D printed bioreactor chamber for tendon tissue engineering

This study developed a low-cost, universally adaptable, six-well tensile bioreactor chamber fabricated by fused filament fabrication (FFF) 3D printing to improve reproducibility and comparability across tendon tissue engineering studies using different actuator platforms. The chamber body and tensile arm components were printed in PLA and waterproofed/sterilized via a coating workflow (XTC-3D oxirane epoxy resin for impermeability plus Sylgard-184 PDMS well-base coating to reduce adhesion). Biocompatibility was validated by LDH assay, showing that fully cured and repeatedly PBS-washed resin/PDMS components were non-cytotoxic. The chamber provided six isolated culture wells (~8 mL capacity) and uniform displacement delivery across wells (validated up to 50% strain with <~0.6% deviation). Biological validation was performed using human MSC-derived tissue-engineered tendons formed in fibrin hydrogels within custom anchor frames, followed by cyclic tensile stimulation (5% strain,0.5 Hz,5 h/day,5 days/week for 21 days). Cyclic loading increased tissue alignment and collagen organization (H&E, Picrosirius Red under polarized light), prevented matrix calcification observed in static controls (Alizarin Red), and increased collagen Iα1 production (~2.5-fold) with reduced collagen IIIα1 trends by dot blot, consistent with a tenogenic phenotype.