Posters-Accepted Abstracts: Biol Syst Open Access
The quest for microscopes that can surmount light diffraction limits hasresulted in Scanning probe microscopes. However many of these are not ideal for living biology. The scanning ion conductance microscope (SICM) bridges the gap between the resolutions of (a)the Atomic Force Microscope (AFM) or the scanning electron microscope, and (b) the functional capabilities of conventional light microscopy. The SICM is a high-resolution (submicron) microscope similar in principle to the AFM. But while morphologically definingmembrane near nanostructure, unlike the AFM, which taps the cell, the SICM is notouch. A nanopipette, on a three-axis piezo-actuator scans the nanopipette over living preparations in physiological solutions. Ion current is measured between the pipette tip and the sample. (The sample stage can also move - with pipettestationary.) Feedback control maintains a given ion current and thus maintains distance between the sample and the pipette (no touch). Recorded XYZ pipette movement generate 3D topographical images of live biological samples. The hollow nanopipette probe provides added modalities�??, enabling functional studies.The same pipette and feedback control, precisely targets, and patches, discrete regions of the cell for ion channel recording. The SICM can include fluorescence (pipette stationary, sample moves) facilitating structure-function correlations. Also, as a �??mechanical�?� instrument it can precisely measure local membrane compliance (Young�??s Modulus). Moreover, applied pressure through the pipette,targeting selected areas indents the membrane, liberating intracellular calcium by mechanosensitive processes. All this is on living tissue. The SICM as a high resolution multifunctional instrument has significant future potential.