Visible Light-Based Three-Dimensional Printing of Drug-Loaded Scaffolds: A Comparative Study of Initiating Systems and Drug Release Profiles

Three-dimensional (3D) printing offers a transformative approach to personalized medicine, particularly in the fabrication of bespoke drug delivery systems. Our previous work showcased the customization of release profiles through intricate channel-pore structures and geometries of 3D printed scaffolds using photoinitiator reversible addition–fragmentation chain-transfer polymerization under UV light. Building upon this foundation, our current study further refines the control of drug release kinetics from 3D printed drug-loaded scaffolds by exploring three different photoreaction mechanisms. We introduce a versatile and widely applicable visible light-based rapid high-resolution 3D printing method, marking a significant departure from traditional high-energy UV light. This shift enables high-resolution printing while addressing constraints associated with high-energy UV light, thereby broadening the scope of accessible materials in 3D printing applications. Our study demonstrates that both the photopolymerization activation mechanism and the design of the interconnected channel-pore structure critically affect the drug release rate and amount. Specifically, the type of photopolymerization significantly influences the cross-linking density and the uniformity of the cross-linked networks, which in turn affect the swelling ratio and the homogeneity of drug distribution within the scaffolds. The drug release profiles showed a clear correlation with scaffold porosity, where higher porosity facilitated greater water ingress and enhanced drug release. However, beyond a certain threshold, further increases in porosity had a negligible impact. These findings highlight the potential of optimizing both the photopolymerization activation mechanism and the design of the interconnected channel-pore structure to control drug release from 3D printed scaffolds for personalized medicine.