Researchers at theUniversity of Creteand theFoundation for Research and Technology-Hellas(FORTH/IESL) have reported a one-step strategy for fabricating bioactive 3D hydrogel scaffolds using curcumin as a multifunctional photoinitiator in two-photon polymerization (2PP). Posted as apreprintlast month, the study says curcumin serves two roles: it enables high-resolution 3D printing while simultaneously imparting antibacterial properties during fabrication, removing the need for post-print modification.

2PP is widely used for micro-scale scaffold fabrication in tissue engineering. However, its broader adoption in hydrogel systems has been constrained by the lack of photoinitiators that combine high nonlinear absorption efficiency with cytocompatibility. Conventional initiators such as Irgacure 2959 exhibit low two-photon absorption cross sections under near-infrared excitation, requiring higher laser intensities that increase the risk of thermal damage and reduced feature fidelity.

Enhanced nonlinear absorption through GelMA–curcumin interaction

In the reported work, curcumin, a naturally derived polyphenol from turmeric, was incorporated into a 10% (w/v) GelMA formulation. Open-aperture Z-scan measurements showed that the GelMA/curcumin mixture achieved a two-photon absorption cross section of approximately 1500 Goeppert Mayer (GM), compared to roughly 320 GM for curcumin alone.

The researchers attribute this enhancement to interactions between curcumin and hydrophobic amino acid residues in the GelMA backbone. These interactions promote localized aggregation and stronger electronic coupling, increasing nonlinear energy deposition within the focal voxel during printing.

Parametric fabrication studies revealed a broad processing window. The GelMA/curcumin formulation supported polymerization at laser intensities as low as 0.15 TW/cm², with scanning speeds up to 52 mm/s. In comparison, GelMA formulations containing Irgacure 2959, Eosin Y, or Rose Bengal exhibited narrower processing windows and, in some cases, thermal damage at elevated intensities.

Printing complex TPMS and bone-like lattices

Using multiphoton lithography, the team fabricated square lattices, gyroid and Schwarz diamond triply periodic minimal surface (TPMS) architectures, and bone-like lattice structures. Scanning electron microscopy confirmed pore sizes ranging from single-digit microns to over 150 μm, depending on geometry. Optical microscopy of hydrated samples indicated that scaffold architectures remained stable after swelling.

TPMS geometries are widely used in regenerative medicine due to their continuous curvature and high surface-to-volume ratio, which improve nutrient diffusion and cell infiltration.

Stem cell compatibility and dual antibacterial function

Source: 3D Printing Industry