Visible Light-Based\nThree-Dimensional Printing of\nDrug-Loaded Scaffolds: A Comparative Study of Initiating Systems and\nDrug Release Profiles

Three-dimensional (3D) printing offers a transformative\napproach\nto personalized medicine, particularly in the fabrication of bespoke\ndrug delivery systems. Our previous work showcased the customization\nof release profiles through intricate channel-pore structures and\ngeometries of 3D printed scaffolds using photoinitiator reversible\naddition–fragmentation chain-transfer polymerization under\nUV light. Building upon this foundation, our current study further\nrefines the control of drug release kinetics from 3D printed drug-loaded\nscaffolds by exploring three different photoreaction mechanisms. We\nintroduce a versatile and widely applicable visible light-based rapid\nhigh-resolution 3D printing method, marking a significant departure\nfrom traditional high-energy UV light. This shift enables high-resolution\nprinting while addressing constraints associated with high-energy\nUV light, thereby broadening the scope of accessible materials in\n3D printing applications. Our study demonstrates that both the photopolymerization\nactivation mechanism and the design of the interconnected channel-pore\nstructure critically affect the drug release rate and amount. Specifically,\nthe type of photopolymerization significantly influences the cross-linking\ndensity and the uniformity of the cross-linked networks, which in\nturn affect the swelling ratio and the homogeneity of drug distribution\nwithin the scaffolds. The drug release profiles showed a clear correlation\nwith scaffold porosity, where higher porosity facilitated greater\nwater ingress and enhanced drug release. However, beyond a certain\nthreshold, further increases in porosity had a negligible impact.\nThese findings highlight the potential of optimizing both the photopolymerization\nactivation mechanism and the design of the interconnected channel-pore\nstructure to control drug release from 3D printed scaffolds for personalized\nmedicine.