BODIPY-Loaded ZIF-8 Nanomaterials for Enhanced Photodynamic Inactivation of Staphylococcus aureus

Abstract

The rise of antibiotic-resistant pathogens has heightened the demand for innovative treatments, promoting advanced photodynamic materials for targeted microbial inactivation. Here, we report the synthesis of a series of photosensitizer nanomaterials consisting of BODIPY (BDP) dyes confined within ZIF-8, prepared via a straightforward one-pot nanoprecipitation method. The morphology of these materials was analyzed by SEM and TEM, and spectroscopic characterization confirmed the successful incorporation of BDP dyes within the porous ZIF-8 framework. Encapsulation significantly improved the ability of BDPs to generate reactive oxygen species (ROS) in aqueous media, with the brominated derivative, Br2BDP@ZIF-8, exhibiting particularly high production of singlet molecular and superoxide anion radicals. The photodynamic activity of Br2BDP@ZIF-8 was further demonstrated by its efficient degradation of tryptophan through a type II photoprocess. In addition, encapsulating BDPs within the ZIF-8 framework significantly enhanced their photostability compared with the free dyes. Antimicrobial assays revealed the strong potential of these nanomaterials for photoinactivation of Staphylococcus aureus. Under green light irradiation, Br2BDP@ZIF-8 achieved a 99.999% reduction in the bacterial population in liquid suspensions after exposure to a light fluence of 5 J/cm2. Fluorescence images of S. aureus showed the characteristic green fluorescence of BODIPY, indicating an effective interaction with BDP@ZIF-8. Furthermore, effective eradication of S. aureus contamination (>97%) was found on surfaces irradiated with only 0.9 J/cm2. These findings highlight the potential of BDP-loaded ZIF-8 nanomaterials as robust and efficient photosensitizing agents for bacterial elimination, offering promising applications in the photokilling of bacterial cells and surface decontamination.