Selective Inactivation of Resistant Gram-Positive Pathogens with a Light-Driven Hybrid Nanomaterial

Abstract

Herein, we present a straightforward strategy to disperse highly insoluble photosensitizers in aqueous environments, without major synthetic efforts and keeping their photosensitizing abilities unaffected. A layered nanoclay was employed to adsorb and to solubilize a highly efficient yet hydrophobic Si(IV) phthalocyaninate in water. The aggregation of the photoactive dye was correlated with its photophysical properties, particularly with the ability to produce highly cytotoxic singlet oxygen. Moreover, the resulting hybrid nanomaterial is able to selectively photoinactivate Gram-positive pathogens, due to local interactions between the bacterial membranes and the negatively charged nanodiscs. Nanotoxicity assays confirmed its innocuousness toward eukaryotic cells, showing that it constitutes a new class of "phototriggered magic bullet" for the inactivation of pathogens in phototherapy, as well as in the development of coatings for self-disinfecting surfaces.

Labeling and Selective Inactivation of Gram‐Positive Bacteria Employing Bimodal Photoprobes with Dual Readouts

“…Moreover, Si IV phthalocyanine‐loaded layered nanoclays developed in our labs have shown a remarkable efficiency in the selective inactivation of antibiotic‐resistant Gram‐positive pathogens. , Despite their potential for diagnostics or therapy, it is clear that the long term toxicity associated to the permanence of aluminosilicate‐based nanoparticles in living organisms and in the environment severely limit their application. Therefore, biocompatible and biodegradable photosensitizers based on luminescent Si IV phthalocyanine‐based PS would constitute ideal theranostic agents for the directed fluorescent labeling and inactivation of pathogens, provided that they can be conjugated with a broad range of tailored targeting units that can be selected according to the microorganism.…”

Nanomaterials for removal of waterborne pathogens

“…Besides these metal-based nanoparticles, laponite nanodiscs loaded with Si(IV) phthalocyanine dihydroxide (photosensitizer) was also applied as photocatalytic materials. They were found to be active against resistant Gram-positive pathogens (Grüner et al, 2015). Other issues that need to solved are posttreatment separation of nanomaterials and presence of extracellular polymeric materials (EPS).…”

Enhanced visible light promoted antibacterial efficiency of conjugated microporous polymer nanoparticles via molecular doping

“…[25][26][27][28] Especially singlet oxygen is well known as the main reactive oxygen species responsible for cell death in antimicrobial photodynamic therapy. [29][30][31] Besides the material class choice perspective, there are a vast number of useful structural modification methods of semiconductor-based materials in order to enhance the pristine functionalities. Among them, the introduction of foreign impurities into a semiconductor, the so-called doping method, has been largely employed as an efficient strategy to manipulate the electronic structure of semiconductors, and thus, to achieve the desired control over the optical, conductive, magnetic or other physical properties for targeted applications.…”