Photopolymerization Strategies for Macromolecular Network Engineering in Biomaterials.

UV-induced polymerization and photocrosslinking have become versatile tools for engineering advanced biomaterials, providing rapid reaction kinetics, spatial-temporal control, and compatibility with sensitive biological environments. This review integrates the fundamental mechanisms of photopolymerization, cationic photopolymerization, and thiol-mediated photopolymerization with the design principles of key UV-responsive material classes, including hydrogels, smart stimuli-responsive systems, elastomers and thermosets, polymeric networks, and composite or hybrid matrices. Their expanding roles in biomedical technologies are highlighted through applications in drug delivery, bioactive coatings, scaffolds, and photoactivated bioadhesives, as well as in photopolymerization-based additive manufacturing strategies such as digital light processing (DLP) and stereolithography (SLA). The unique advantages of UV-activated systems, such as mild processing conditions, on-demand curing, and compatibility with in situ and minimally invasive procedures, are discussed alongside current constraints, including limited light penetration, oxygen inhibition, cytotoxicity, and application-specific barriers. By linking photochemical fundamentals with application-driven design, this review underscores the growing potential of UV-engineered polymer networks to enable next-generation solutions in tissue engineering, regenerative medicine, and targeted therapeutic delivery.