Stereoisomeric engineering of aggregation-induced emission photosensitizers towards fungal killing

Abstract

Fungal infection poses and increased risk to human health. Photodynamic therapy (PDT) as an alternative antifungal approach garners much interest due to its minimal side effects and negligible antifungal drug resistance. Herein, we develop stereoisomeric photosensitizers ((Z)- and (E)-TPE-EPy) by harnessing different spatial configurations of one molecule. They possess aggregation-induced emission characteristics and ROS, viz. 1O2 and O2−• generation capabilities that enable image-guided PDT. Also, the cationization of the photosensitizers realizes the targeting of fungal mitochondria for antifungal PDT killing. Particularly, stereoisomeric engineering assisted by supramolecular assembly leads to enhanced fluorescence intensity and ROS generation efficiency of the stereoisomers due to the excited state energy flow from nonradiative decay to the fluorescence pathway and intersystem (ISC) process. As a result, the supramolecular assemblies based on (Z)- and (E)-TPE-EPy show dramatically lowered dark toxicity without sacrificing their significant phototoxicity in the photodynamic antifungal experiments. This study is a demonstration of stereoisomeric engineering of aggregation-induced emission photosensitizers based on (Z)- and (E)-configurations.

Micro/Nanorobotic Swarms: From Fundamentals to Functionalities

“…A magnetic microrobotic swarm has been applied in the gastrointestinal and biliary systems of pigs to eradicate the biofilm in biliary stents . While degrading the biofilm, the enzyme-carrying micro/nanorobotic swarms can further generate bactericidal free radicals for killing bacteria. ,,− The addition of swarm motion control has been proven to enhance the cleaning efficacy of the microrobotic swarms on complex topographies, as demonstrated on ex vivo human teeth (Figure E) …”

Acceptor engineering of metallacycles with high phototoxicity indices for safe and effective photodynamic therapy

“…Photodynamic therapy (PDT) is a clinically approved therapeutic modality that has been extensively applied to treat cancer because of its temporal-spatial controllability and minimal side effects. [1][2][3][4][5][6] The PDT mechanism relies on the conversion of an excited photosensitizer (PS) to molecular oxygen, under light irradiation, to generate ROS. [7][8][9][10][11][12] To date, various advanced PSs have been developed, but several obstacles impede their acceptance in biomedicine.…”

Oxidization enhances type I ROS generation of AIE-active zwitterionic photosensitizers for photodynamic killing of drug-resistant bacteria

“…Photodynamic therapy (PDT), that uses external light-activated photosensitizers (PSs) to produce highly oxidizing reactive oxygen species (ROS) to induce cell or microbe death, has recently attracted considerable attention in disease therapeutics owing to its non-invasiveness, limited therapeutic resistance, excellent spatiotemporal selectivity and minimal side effects. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] According to the mechanism and type of ROS generation, there are mainly two types of PSs (type I and type II). [16][17][18][19] To date, most of the reported PSs have come into effect mainly via the highly oxygen-dependent type II pathway, whereas type I PSs with low-oxygen-dependency have rarely been developed because of the lack of a universal structural design strategy, which limits the therapeutic performance of PDT to some extent.…”