Programmable 4D printing of sustainable multifunctional photoresins with tissue-matched mechanics for interfacial tissue regeneration

The integrative regeneration of articular cartilage and subchondral bone remains a major clinical challenge due to the difficulties of mimicking the spatial and compositional complexity of native osteochondral tissues in artificial implants. To overcome these limitations, 3D printing has enabled personalized solutions, going beyond traditional plug-shaped scaffolds that are limited to repairing small, cylindrical focal defects. In this study, we report solvent-free 4D printing of olive oil-derived fatty amide-based acrylate photoresin for osteochondral tissue engineering applications. The physicochemical properties of the printed polymers were fine-tuned using acrylic acid as a comonomer. With optimized printing conditions, the resin can be printed into high-resolution objects with each layer of ∼50-100 μm. Depending on the resin composition, the mechanical properties of the printed polymers vary between ∼200-1400 kPa with ∼210-420% strain under tensile setting, and ∼26-98 MPa at ∼80% strain under compressive setting. The mechanical properties of the printed polymers are comparable to those of various interfacial soft tissues, including ligaments, articular cartilage, and soft collagenous bone, indicating their potential for interfacial tissue engineering applications. Furthermore, the printed polymers showed near-body temperature-responsive shape memory (4D) properties with a recovery ratio of ∼99% for optimized resin composition. In addition, the printed polymers exhibited excellent bactericidal antimicrobial activity against both Gram-negative and Gram-positive bacteria, highlighting their multifunctional nature. More importantly, the printed polymers exhibited good cytocompatibility (cell viability ∼≥90% across all samples compared to control) toward adipose-derived human mesenchymal stem cells, facilitating growth factor-free osteogenic and chondrogenic differentiation, which confirms their potential for osteochondral tissue regeneration. Overall, the newly developed biobased resin offers a low-cost, sustainable alternative for 4D printing of personalized implants for osteochondral tissue regeneration.