A porous 3D biofilm-inspired alginate/gellan hydrogel fabricated via dual-wavelength UV-crosslinking printer: Structural and rheological properties

The advancement of additive manufacturing for biopolymers with spatially tailored properties remains challenging, particularly in multi-material structures. Traditional methods relying on automated sample swapping compromise production speed and interlayer adhesion. Critically, existing biofilm models predominantly use 2D formats that fail to replicate essential 3D microenvironments for structural development and antimicrobial resistance-limiting their physiological relevance. To address both manufacturing and modeling limitations, we introduce a novel dual-wavelength in-place UV crosslinking technique using chemo-selective irradiation (UV-A:390 nm and UV-C:260 nm) in combination with a Norrish Type I photoinitiator to fabricate multi-material macroporous biofilm-inspired architecture with enhanced mechanical and rheological properties, as well as effective 3D architectures for biofilm simulation. An alginate/gellan-inspired hydrogel mimicking biofilm materials enables stiffness modulation via photosensitization tuning. Results demonstrated UV-A yielded softer, flexible networks while UV-C produced stiffer, elastic structures. The application of Norrish type I photoinitiators in combination with in-place UV irradiation-coupled with bioprinter considerably broadened the achievable thermo-mechanical and cytocompatibility with improved build efficiency, overcoming traditional UV-curing limitations for functional multi-material components in advanced manufacturing and physiologically relevant biofilm modeling.