One‐Step Curcumin‐Mediated Multiphoton Lithography for Bioactive 3D Scaffolds

Multiphoton lithography (MPL) stands out among additive manufacturing (AM) techniques by offering sub‐diffraction‐limited resolution (<100 nm), enabling the fabrication of complex 3D scaffolds, however the lack of biocompatible and bioactive photoinitiators remains a bottleneck for functional bio‐manufacturing. Here, a one‐step strategy is presented using curcumin (CUR), a naturally derived polyphenol, as a high‐efficiency multifunctional bioactive photoinitiator for gelatin methacryloyl (GelMA). Nonlinear optical characterization reveals a synergistic interaction between CUR and the GelMA protein backbone, resulting in a significantly enhanced two‐photon absorption cross‐section (σ ≈ 1500 GM) outperforming conventional initiators. This synergy facilitates an exceptionally broad processing window and high‐speed fabrication (up to 52 mm/s) of high‐fidelity, complex architectures, including triply periodic minimal surface (TPMS) and biomimetic bone‐like scaffolds. Beyond its initiation efficiency, CUR imparts intrinsic multifunctionality to the resulting 3D scaffolds. The printed GelMA/CUR constructs exhibit exceptional biocompatibility with mesenchymal stem cells (MSCs) while demonstrating a potent dual‐action antimicrobial response: active photodynamic eradication for both Gram‐negative Escherichia coli (>91%) and Gram‐positive Staphylococcus aureus (>99.9%) bacteria upon blue LED irradiation, combined with a selective passive antifouling effect against E. coli . This all‐in‐one approach transforms the photoinitiator from a fabrication tool into an active material component, eliminating the need for post‐fabrication functionalization.