Polydimethylsiloxanes - Based Fluorescent Probe for HS Detection in Living Cells.

The development of fluorescent probes for HS detection especially in living cells is of great significance due to its fundamental role as signal molecule. A promising scaffold for the development of such probes is polydimethylsiloxanes (PDMS), which is cost-effectiveness, non-toxicity, flexibility, and biocompatibility and easy to post-functionalize. Surprisingly, fluorescent probes for HS detection based on PDMS have not been investigated. Moreover, 4-nitro - 2,1,3-benzoxadiazole (NBD) derivates provides high fluorescence quantum yield, a large molar absorption coefficient, and sensitivity to environmental changes. Through reasonable design and adjustment of substituents on the NBD group, precise control of its fluorescence properties can be achieved. Herein, a novel HS fluorescent probe, P-NBD, was designed and synthesized by a one-step aromatic ring nucleophilic substitution of Cl-NBD with a PDMS derivative. Due to the occurrence of the cleavage reaction strategy and the intramolecular charge transfer process, P-NBD can detect HS via a colorimetric method. The limit of detection is down to 93 nM. P-NBD demonstrated considerable detection capability comparable to other reported types of HS probes. Moreover, the probe can also be utilized for HS imaging in HeLa cells. This work provides new insights into the design and synthesis of novel HS probes while also offering experimental evidence for the application of PDMS in cellular imaging.