A membrane-anchored fluorescent probe for the detection of pH in living cells and NAFLD†

The abnormal pH in cell membranes can lead to disorder in membrane structure and permeability, and is also an important signal of cell cancer. The acidification of the cell membrane can lead to the disorder of cell lipid metabolism and lead to non-alcoholic fatty liver disease (NAFLD). However, fluorescent probes to detect the cell membrane pH have rarely been reported, let alone used to study NAFLD. For this, we developed a fluorescent probe (Mem-pH) that can firmly anchor the cell membrane based on lipophilic action and electrostatic action forces, and successfully detect membrane pH by fluorescence intensity. More importantly, the probe Mem-pH can quantify the pH of different kinds of cell membranes, further demonstrating that the pH of cancer cell membranes is lower than that of normal cell membranes. Furthermore, Mem-pH successfully differentiates and detects different degrees of NAFLD tissues, offering hope for timely diagnosis of NAFLD.