NIR-Triggered Multifunctional NO Nanoplatform for Conquering Thermal Resistance in Biofilms

Photothermal treatment (PTT) has emerged as a promising avenue for biofilm elimination, yet its potential drawbacks, such as local hyperpyrexia and bacterial heat resistance, have posed challenges. To address these concerns, an innovative nanoplatform (Au@mSiO2-arg/ICG) is devised that integrates phototherapeutic and gas therapeutic functionalities. This multifaceted nanoplatform is composed of mesoporous silica-coated Au nanorods (Au@mSiO2), supplemented with l-arginine (l-arg) and indocyanine green (ICG), and is engineered for mild temperature PTT aimed at biofilm eradication. Au@mSiO2-arg/ICG nanoparticles (NPs) show excellent antibacterial effects through the generation of nitric oxide (NO) gas, heat, and reactive oxygen species (ROS) under 808 nm light irradiation. The ROS generated by ICG initiates a cascade reaction with l-arg, ultimately yielding NO gas molecules. This localized release of NO not only effectively curbs the expression of heat shock proteins 70 mitigating bacterial thermoresistance, but also reduces extracellular polymeric substance allowing better penetration of the therapeutic agents. Furthermore, this nanoplatform achieves an outstanding biofilm elimination rate of over 99% in an abscess model under 808 nm light irradiation (0.8 W center dot cm-2), thereby establishing its potential as a dependable strategy for NO-enhanced mild PTT and antibacterial photodynamic therapy (aPDT) in clinical settings. Au@mSiO2-arg/ICG combines phototherapeutic and gas therapeutic features for efficient biofilm elimination. Under 808 nm light, ROS can cause the release of NO from l-arg. Meanwhile, NO suppresses the HSP70 expression to achieve mild PTT and reduces EPS via regulating c-di-GMP. The platform addresses concerns like bacterial heat resistance and offers the potential for NO-enhanced mild PTT and aPDT in clinical applications. image