Biomaterials in 3D bioprinting: Design strategies, material-technique interactions, and biomedical applications

Three-dimensional (3D) bioprinting has emerged as a transformative approach in biomedical engineering, enabling the fabrication of complex, patient-specific constructs through layer-by-layer deposition of biomaterials and living cells. This review critically synthesizes the role of biomaterials in 3D bioprinting by comparing how material properties, fabrication techniques, and biological requirements interact to determine construct performance across different biomedical applications. Unlike many existing reviews that discuss materials, techniques, and applications separately, this review focuses on the coupled interactions between biomaterial chemistry, fabrication methods, and application-specific requirements across multiple tissue systems. Across these applications, no single biomaterial satisfies all design requirements, leading to compromises between mechanical strength, printability, and biological performance. Hard tissue applications prioritize thermoplastic polymers and ceramics for structural integrity, while soft tissue engineering relies on hydrogel-based bioinks. Printing techniques such as extrusion, inkjet, and stereolithography impose constraints related to resolution, viscosity, and cell viability, driving the use of composite biomaterials and hybrid fabrication strategies. Despite significant advances, major challenges remain, including mechanical mismatch, limited vascularization, reproducibility, and lack of long-term in vivo validation. This review highlights 4D printing, smart biomaterials, and artificial intelligence-assisted design as emerging strategies to advance clinically translatable constructs. Taken together, successful bioprinting is governed by coupled biomaterial-technique interactions within specific clinical contexts.