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.