Alkyl chain regulated cytomembrane and mitochondria targeting fluorescent probes for ratiometric sensing SO2 and its bio-application in mice model

Abstract

Abstract Sulfur dioxide has been recognized as an important signaling molecule which can be generated enzymatically in mitochondria during oxidation of sulfur-containing amino acids. Meanwhile, cell membrane plays an important role in signal transduction. Therefore, the study of SO2 effects has proven to be challenging due to the lack of reliable tools for monitoring SO2 in different subcellular organelle. Herein, we designed two probes CPA-1 and CPA-2 based on coumarin derivatives. The cyano substituted double bond of the two probes were selected as the SO2 response site, and the length of the alkyl side chain of the pyridine salt was used to regulate the hydrophobicity to achieve the efficient targeting of the mitochondria and the cell membrane, respectively. Importantly, CPA-1 and CPA-2 shows ratiometric fluorescence response towards SO2 with highly sensitive and selective. Moreover, cell-imaging demonstrated that CPA-1 and CPA-2 possesses good mitochondria-targeted and cell membrane-targeted ability, respectively. Additionally, CPA-1 and CPA-2 were perfectly used for detection of SO2 in mice. We expect that the work will provide a useful tool and strategy for studying and visualizing signal molecules on the cell membrane in vivo.