Lignin-Based Visible Light-Triggered Nitric Oxide Nanogenerator for Antibacterial Applications

Nitric oxide (NO) has received growing attention as an effective antibacterial agent with broad-spectrum activity and a low risk of resistance. However, it remains challenging to develop effective, controllable, and biocompatible NO-releasing materials. Here, we report a novel NO nanogenerator (AL-BNN6-PEG) self-assembled by lignin, a UV-absorbing and hydrophobic NO donor (<i>N</i>,<i>N</i>'-di<i>sec</i>-butyl-<i>N</i>,<i>N</i>'-dinitroso-1,4-phenylenediamine, BNN6), and PEG-DSPE₂₀₀₀. It was discovered that upon visible light irradiation (450-460 nm), BNN6 can be decomposed by lignin within micellar nanoparticles via a photoinduced electron transfer mechanism in the aqueous medium. Lignin not only served as a sustainable carrier, enhancing the water dispersity of BNN6, but also acted as a biocompatible photosensitizer, triggering BNN6 decomposition with the concomitant release of NO. As a result, the micellar nanoparticles displayed superior antibacterial effects against Gram-negative and Gram-positive bacteria upon visible light illumination. Moreover, MTT assay revealed the negligible cytotoxic effect of the micellar nanoparticles to the mouse fibroblast cells (L929). This research provides more insight into the BNN6 decomposition mechanism and demonstrates a straightforward, effective, and biocompatible strategy for controlled NO-mediated antibacterial applications.