Cluster and Kill: the Use of Clustering-Triggered Emission Materials for Singlet Oxygen Photosensitization in Antimicrobial Photodynamic Therapy

The emergence of light-based technologies is revolutionizing modern medicine and healthcare by enabling precise disease diagnosis and treatment through various luminescent agents and imaging techniques. Despite challenges like biocompatibility, spectral tuning, and synthesis complexity, the primary issue is the aggregation-caused quenching of emission on high concentrations or physiological conditions. In light of these problems, Clustering-Triggered Emission (CTE), which involves the formation of atomic clusters to induce light absorption and the luminescence of unconventional chromophores, represents an all-in-one solution to the challenges identified. Given the potential for CTE materials to behave in ways previously only associated with conventional chromophores, it seems reasonable that highly oxidative reactive oxygen species can be formed from CTE excited states. The results demonstrate that it is possible to transfer the excess energy from the CTE long-lived excited states to molecular oxygen, thereby producing singlet oxygen. It is also noteworthy that over 99.9% of Staphylococcus aureus cells can be eradicated using fluences comparable to those used in traditional systems under violet light irradiation. Uncovering these photophysical properties of CTE opens the door to a revolutionary breakthrough that can disrupt conventional photodynamic therapy and usher in a new era of CTE-based photosensitizers.