Mapping of enzyme activity by detection of enzymatic products during AFM imaging with integrated SECM–AFM probes

With the integration of submicro- and nanoelectrodes into atomic force microscopy (AFM) probes using microfabrication techniques, an elegant approach combining scanning electrochemical microscopy (SECM) with AFM has recently been introduced. Simultaneous contact mode imaging of a micropatterned sample with immobilized enzyme spots and imaging of enzyme activity is shown. In contrast to force spectroscopy the conversion of an enzymatic byproduct is directly detected during AFM imaging and correlated to the activity of the enzyme.