Formulation-Driven Design of Antimicrobial Hydrogel Wound Patches 3D-Printed by Digital Light Processing: Mapping Polysaccharide and Nanoparticle Effects

Wound dressings must balance antimicrobial efficacy with the printability limits imposed by nanoparticle-mediated ultraviolet attenuation during digital light processing 3D printing. Here, we develop process-structure-property relationships for poly(ethylene glycol) diacrylate (PEGDA)-based hydrogel wound patches containing Ag/ZnO-derived antimicrobial phases and polysaccharide/cellulose modifiers (cellulose nanofibrils, chitosan, or alginate). Beer-Lambert analysis shows that nanoparticle loading reduces optical penetration depth at 405 nm to 1.04-1.28 mm, narrowing the usable curing margin so that radiant exposure exceeds the critical energy by only 4%-5%. Flory-Rehner analysis of swelling reveals formulation-dependent crosslink density: alginate lowers effective crosslink density by 45% vs. neat PEGDA and increases mesh size from 0.42 to 0.60 nm. This network loosening drives 1.5× variation in water vapor transmission rate (WVTR; 346-518 g·m^{- 2}·day^{- 1}) and a 7× range in wettability (11.5°-81.1°). Two-way factorial analysis identifies polysaccharide type as the dominant driver of swelling (87.5% of variance) and antimicrobial efficacy (>50%), while nanoparticle type controls contact angle (60.1%) and WVTR (76.9%). The Ag + chitosan formulation (S5) achieves 23-24 mm inhibition zones against Escherichia coli and Bacillus sp. via chitosan-facilitated Ag⁺ diffusion plus intrinsic contact-killing. Inductively coupled plasma optical emission spectroscopy confirms cumulative Ag⁺ release (32.7 mg·L^{- 1} over 14 days), while Zn^{2 +} remains immobilized below detection.