In situ chemical sensing by using scanning probe microscope

Scanning electrochemical microscopy (SECM), which utilizes microelectrodes as a probe to measure the chemicals released and consumed by cells as current signal, is a promising tool for measuring the metabolites of cells. We have improved SECM resolution for single cell imaging by miniaturizing the size of the electrode and developing hybrid system of SECM and scanning ion conductance microscopy (SICM), which utilizes nanopipette as a probe to measure live cell topography. SECM-SICM provides simultaneous imaging of concentration profiles of chemical substances and cell surface topography. Using this system, we successfully measured the release of neurotransmitters from PC12 cells. In addition, the nanoscale electrodes are useful for intracellular chemical detection by inserting the electrodes into cells and measured reactive oxygen species (ROS).