Single-atom replacement as a general approach towards visible-light/near-infrared heavy-atom-free photosensitizers for photodynamic therapy

Abstract

<p>Thio-based photosensitizer: a general strategy for preparing visible/NIR light absorbing heavy-atom-free photosensitizers was developed by performing a simple sulfur-for-oxygen atom substitution within existing fluorescent molecules.</p>

Thionated organic compounds as emerging heavy-atom-free photodynamic therapy agents

“…This chemistry was further extended through the incorporation of a dual-functional morpholine group (i.e., electron-donating and lysosome-targeting) into the thionaphthalimide, which was shown to generate ROS in the lysosomes of HeLa cells and to cause cell death upon light irradiation. 79 Xiao and co-workers 80,81 have recently generalized the thionation approach to design heavy-atom-free photosensitizers that can be photoactivated by visible or near-infrared light. Thionation of the carbonyl groups leads to near-unity singletoxygen quantum yields and large molar absorption coefficients at wavelengths as long as 760 nm (Fig.…”

“…The developed thionated photosensitizers do not exhibit cytotoxicity in the dark, while show good photodynamic efficacy against cancer cells and 3D multicellular tumor spheroids. 80 The authors further conjugated the thionated photosensitizers to the trastuzumab, a monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2), to achieve tumor-specic delivery and demonstrated their tumor-specic therapeutic activity against a HER2-positive cell line. Collectively, these results indicate the promising value of thionated photosensitizers as heavy-atom-free photodynamic agents for PDT applications based on intracellular generation of ROS.…”

Quantitative interrogation of protein co-aggregation using multi-color fluorogenic protein aggregation sensors

“…Future color enrichment of the sensor toolbox by developing novel protein aggregation sensors from solvatochromic uorophores, uorescent molecular rotors, and AIEgens may improve the detection multiplexity for more complex disease model systems, such as amyotrophic lateral sclerosis disease. [93][94][95]…”

Site‐Specific Incorporation of a Photoactivatable Fluorescent Amino Acid

“…In 2019, we made improvements in this field by developing a general thio‐caging strategy for preparing photoactivatable probes [33,34] . Our approach introduces a minimal molecular modification within an existing fluorescent molecule; namely a single sulfur‐for‐oxygen atom substitution [35] .…”

“…Importantly, compared to the strong fluorescence of Acd, SAcd had a quantum yield below 0.1 % and exhibited almost no fluorescence in either DMSO or water (Table S1). Earlier studies of similar thiocarbonyl‐based fluorophores have suggested that the sulfur for oxygen exchange induces an intramolecular photo‐induced electron transfer and enhances intersystem crossing to generate non‐emissive triplet states, both of which contributed to the quenching of fluorescence [33,34] …”