Three-dimensional-printed shape-memory composite scaffold for meniscus repair

ObjectiveThe meniscus has poor intrinsic healing capacity, particularly in avascular regions. Meniscal injury is strongly associated with progressive knee dysfunction, chronic pain, and accelerated osteoarthritis development. Current treatments, such as allografts and partial meniscectomy, are limited by donor scarcity and secondary joint degeneration. Therefore, this study aimed to develop a regenerative meniscal scaffold with integrated biomechanical and biological functionality.MethodsA biomimetic composite scaffold was fabricated via low-temperature three-dimensional printing using poly(D,L-lactic acid-co-trimethylene carbonate) and bacterial cellulose. Native meniscal architecture was reproduced using micro-computed tomography-based modeling, and interconnected porosity was designed to promote cell infiltration. Material integration employed dichloromethane as a shared solvent, enabling dual-ink (poly(D,L-lactic acid-co-trimethylene carbonate) + bacterial cellulose) co-printing. Scaffold performance was assessed using scanning electron microscopy morphology, porosity and water absorption assays, mechanical testing, Fourier-transform infrared spectroscopy, and in vitro cytocompatibility studies with rat bone mesenchymal stem cells.ResultsThe scaffold exhibited a tensile modulus of 16.6 MPa and compressive modulus of 2.97 MPa, closely matching native meniscal mechanics. Porosity reached 63.57% ± 5.72%, supporting cell adhesion, while water absorption exceeded 138% after 7 days. Notably, the scaffold exhibited temperature-responsive shape memory behavior, allowing minimally invasive implantation and anatomic recovery at 37°C. Bone mesenchymal stem cells exhibited 95% viability (live/dead staining), significant proliferation (cell counting kit-8), and spontaneous chondrogenic differentiation (SRY-box transcription factor 9/collagen type II (SOX9/COLII) expression) without exogenous induction.ConclusionThis three-dimensional-printed poly(D,L-lactic acid-co-trimethylene carbonate)/bacterial cellulose composite scaffold integrates biomimetic mechanics, shape-memory functionality, and pro-chondrogenic bioactivity, offering a promising strategy for meniscal regeneration. Further in vivo studies are warranted to confirm long-term efficacy and clinical translational potential.