Construction of bi-layered osteochondral structures using DLP bioprinting with multi-component comprised bioink

Osteoarthritis is the most common chronic degenerative joint disease worldwide. Effective treatment of osteochondral defects requires multifunctional constructs with mechanical properties that support regeneration of both cartilage and subchondral bone. Such constructs demand bioinks with both osteogenic and chondrogenic capacities, as well as fabrication methods capable of producing multilayered structures that mimic the architecture and function of native osteochondral tissue. In this study, we aimed to develop: (1) multifunctional region-specific alginate-based bioinks incorporating α-tricalcium phosphate (α-TCP), RGD peptide, and N-cadherin peptide to enhance targeted cell differentiation, and (2) an integrated fabrication methodology for generating bi-layered osteochondral constructs. Methacrylated alginate (MA)-based bioinks were fabricated into bi-layered constructs via digital light processing (DLP) bioprinting, and the activity of the encapsulated cells was evaluated. The upper chondrogenic layer incorporated N-cadherin peptide to preserve a stable chondrogenic phenotype, while the lower osteogenic layer containing RGD peptide and α-TCP enhanced osteogenic activity and mechanical properties. The resulting integrated bi-layered constructs demonstrated distinct region-specific biological activities and structural integrity, indicating their feasibility for osteochondral tissue regeneration.