Multifunctional fluorescence probe for detecting viscosity, ONOO– and polarity in vitro and vivo with three channels

The cellular microenvironment (viscosity and polarity) and ONOO - play significant effects on the maintenance of redox balance, signal transmission, and normal cell operation, even closely associated to the onset of various diseases. Therefore, we designed and synthesized the targeted mitochondrial probe ( VNP - M ) featuring three distinct switch-on modes for detecting viscosity, ONOO - and polarity. The emission spectrum of VNP - M displayed remarkable response for viscosity at 680 nm and ONOO - at 580 nm, respectively. Meanwhile, there was a satisfying correspondence between the area under curve (AUC) of 454–654 nm and the polarity. The fluorescence change mechanism was elaborated in detail by theoretical calculation. The VNP - M showed excellent bioimage application ability for confirmation of cancer cells and diabetes diagnosis in vitro and in vivo. More importantly, leveraging VNP - M , we confirmed for the first time that metformin can alleviate diabetes by inhibiting ferroptosis via the detection of viscosity, polarity and ONOO - . Therefore, the VNP - M provided a potential tool for exploring disease status and process through simultaneous measure of viscosity, ONOO - and polarity in mitochondria with three-channel.