Personalized bioactive 3D printed scaffolds for bone and cartilage repair: Engineering strategies toward clinical precision regeneration

Purpose Three-dimensional (3D) printing has become a game changer in regenerative medicine because it can create patient-specific bioactive scaffolds for the repair of bone and cartilage. This work aimed to investigate the design principles, materials, and functionalization means behind developing 3D-printed scaffolds that can try to mimic the hierarchical architecture and biological characteristics of native osteochondral tissues. Methods A thorough review of currently available 3D printing processes, including fused deposition modeling (FDM), stereolithography (SLA), selective laser sintering (SLS), extrusion-based, and inkjet bioprinting, was conducted. The review focused on natural polymers (collagen, gelatin, chitosan, and alginate), biodegradable synthetic polymers (PLA, PCL, PLGA), and bioactive ceramics (hydroxyapatite, β-tricalcium phosphate, bioactive glass) for scaffold fabrication. The biological functionalization of scaffolds through techniques involving growth factors, peptides, stem cells, and antimicrobial agents was discussed for promoting osteogenesis, chondrogenesis, vascularization, and immunomodulation. Results Composite scaffolds made with a combination of natural and synthetic materials have shown increases in mechanical strength, biocompatibility, and osteoconductivity. Prefclinical in vivo studies have shown greater efficacy for bone and cartilage regeneration, and early trials have confirmed feasibility for translation. The combination of artificial intelligence (AI) and digital twin technology will allow for predictive modeling and optimization of scaffold architecture and patient-specific modeling. Nonetheless, obstacles remain that prevent effective large-scale production, government approval, long-term safety and effectiveness, and affordability. Conclusions 3D-bioprinted bioactive scaffolds represent remarkable potential for customized regenerative medicine applications, offering patient-specific, multifunctional, and clinically adaptable strategies for osteochondral defect repair. Future directions will focus on standardized construction protocols, developing robust regulatory pathways, and initiating extensive clinical validation to support appropriate clinical translation.