Synthesis of BODIPY-Loaded ZIF-8 Nanomaterials with Enhanced Fluorescent and Photodynamic Properties

The increasing prevalence of antibiotic-resistant pathogens has intensified the need for advanced photodynamic materials capable of selectively targeting microbial cells. In this work, we report the synthesis and characterization of a series of photosensitizing nanomaterials based on BODIPY (BDP) dyes encapsulated within the metal–organic framework ZIF-8. Two BDP derivatives were employed: 4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (H₂BDP) and its dibrominated analogue, 2,6-dibromo-4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (Br₂BDP). The latter was synthesized by bromination of H2BDP with N-bromosuccinimide in (trifluoromethyl)benzene, affording Br₂BDP in 97% yield. Encapsulation of H₂BDP and Br₂BDP into ZIF-8 was achieved through a one-pot nanoprecipitation method. To maximize dye incorporation, the BDP derivatives were introduced at the initial stage of ZIF-8 formation by slowly adding a solution of zinc nitrate and BDP to a methanolic solution of 2-methylimidazole. The resulting nanomaterials were isolated by centrifugation, washed with methanol and dichloromethane, and dried under vacuum to afford H₂BDP@ZIF-8 and Br₂BDP@ZIF-8. Their morphology was investigated by transmission electron microscopy (TEM), whileUV–visible spectroscopy confirmed the successful incorporation of the dyes within the porous framework. Encapsulation markedly enhanced the fluorescence emission ofH₂BDP in aqueous media and significantly improved the photostability of Br₂BDP, reducing photobleaching compared to the free dye under irradiation. These results demonstrate the potential of BDP-loadedZIF-8 nanomaterials as efficient fluorescent and photodynamic platforms for the detection and photoinactivation of pathogenic microorganisms.