Simultaneous Quantitation of Na+and K+in Single Normal and Cancer Cells Using a New Near-Infrared Fluorescent Probe

Considering the important functions of cellular Na+ and K+ together with their cooperative efforts on various biological processes, it is significant to simultaneously detect Na+ and K+ at a single-cell level. Here, we present a novel method to discriminate and quantify simultaneously Na+ and K+ in single cells using a new near-infrared fluorescent probe associated with microchip electrophoresis. The fluorescent probe selectively responds to both Na+ and K+. The microchip electrophoresis allows accurate single-cell manipulation and effective distinction of Na+ and K+. Based on the method, the concentration of Na+ and K+ in single normal and cancer cells was compared, and the variation of Na+ and K+ in single cancer cells during the early stage of apoptotic volume decrease was monitored, which would help us to better understand the critical roles of Na+ and K+ in malignant cells and apoptosis. This method has paved a new way for the research of the synergistic function of Na+ and K+ in the regulation of various biological processes at a single-cell level.