Curcumin-capped SeNPs: An AIE-active photodynamic nanoplatform for dual antimicrobial and anti-inflammatory applications

The growing threat of multidrug-resistant (MDR) pathogens drives interest in multifunctional nanomaterials that combine antimicrobial efficacy with inflammation control. Herein, a novel one-step, light-driven synthesis of curcumin-capped selenium nanoparticles (CurSeNPs) stabilized with PEG is reported. The influence of synthesis irradiation time (1–4 min) on the photochemical and photophysical properties was investigated. The resulting spherical nanoparticles contain covalently incorporated bioactive curcumin within the PEG network via photoreduction. Photophysical characterization demonstrated a pronounced aggregation-induced emission (AIE) effect. While CurSe 1 min showed the highest singlet oxygen (1O2) yield (5.24-fold enhancement), CurSe 3 min exhibited the longest fluorescence lifetime (1.01 ns) and moderate 1O2 (2.71-fold enhancement). CurSe 3 min was selected as optimal due to its superior balance of colloidal stability (∼-34 mV), fluorescence, and photodynamic activity. Antimicrobial assays revealed broad-spectrum dark activity against Escherichia coli, Staphylococcus aureus, Acinetobacter baumannii, and Candida albicans. Notably, blue-light irradiation (460 nm, 15 min, ∼27 J/cm2) enabled CurSe 3 min to achieve a 2.54 log reduction against MDR A. baumannii (vs. 0.92 log for free curcumin; p < 0.01), where the 1O2 enhancement closely correlated with a 2.76-fold antimicrobial improvement. In RAW 264.7 cells, CurSeNPs induced dose-dependent cytotoxicity and suppressed NO production in the dark. These dark effects were not reversed by catalase or thiourea, indicating ROS-independent mechanisms, such as direct nanoparticle–cell interactions. In conclusion, green-synthesized CurSeNPs represent a promising multifunctional nanoplatform that combines enhanced photophysical properties, broad-spectrum antimicrobial activity, and anti-inflammatory effects, positioning them as versatile candidates for wound infection management.