Scanning Electrochemical Microscopy for Bioimaging

Scanning electrochemical microscopy (SECM) is a scanning probe technique where typically micro- or nanoelectrodes are translated in close proximity to a specimen immersed in an electrolyte solution. The flux of redox active species between the SECM probe and the sample can be used to map local surface reactivity, to record the sample topography, or to manipulate the microenvironment of surfaces for micropatterning. Because SECM can be used in phosphate-buffered solutions with probes acting in contact-less or soft-contact mode, the technique is very attractive for the characterization of biological samples. Compared to microscopic techniques, the advantages of SECM include that the capability of extracting electrochemical information in samples and avoiding potential optical interferences, e.g., from sample color-background. In this article, the principles of SECM bioimaging are introduced: first for the investigation of biosensors with antibody, DNA, or enzyme modification, second for the imaging of live cells, and third for mapping biomarkers in tissues.