Near-infrared light triggered photodynamic and nitric oxide synergistic antibacterial nanocomposite membrane

As an emerging bactericidal strategy, photodynamic therapy (PDT) exhibits great potential to combat various pathogenic infections, but its antibacterial efficacy may be compromised, generally owing to its shallow penetrability of short-wavelength (UV/Vis) light as well as short diffusion length and lifespan of the generated reactive oxygen species (ROS). Herein, we present a method for developing a nitric oxide (NO)-assisted PDT nanocomposite membrane with significantly enhanced bactericidal performances, upon a single near-infrared (NIR) light irradiation. Hierarchically structured nanoparticles (UCNP@PCN), composed of upconversion nanoparticles (UCNPs) and porphyrinic MOFs (PCN-224) are initially prepared. After being doped with L-arginine (LA), the nanoparticles are incorporated into polyvinylidene fluoride (PVDF) matrix to get electrospun nanocomposite membrane (UCNP@PCN@LA-PVDF). Upon NIR light irradiation (980 nm), this UCNP@PCN@LA-PVDF can generate sufficient ROS, which not only acts as main bactericidal agent in PDT but also induces the loaded LA to produce NO, eventually realizing the NO-assisted PDT antibacterial behavior. The generated NO exhibits a larger sterilization area as compared to that of the ROS, demonstrating a vital complementary advantage in facilitating PDT antibacterial efficacy as proven in vitro and in vivo tests. This type of nanocomposite membrane may find unique biomedical applications where both highly enhanced PDT antibacterial effects and deep penetration of NIR light are desired.