In this work we analyzed the effect of the atomic force microscopy probe tip apex shape on Kelvin Probe Force Microscopy (KPFM) potential sensitivity and spatial resolution. It was found that modification of the apex shape from spherical to planar upon thinning of the conductive coating leads to enhanced apex contribution to the total electrostatic force between the probe and the sample. The effect results in extended potential sensitivity and spatial resolution of KPFM. Experimental results were supported by calculations.

There is an unmet need for researchers in life sciences and clinical pathology to obtain untainted target cells with very high accuracy, which are suitable for subsequent genome and protein analysis. In this paper, an electrostatic capture laser microdissection technology (ECM) is proposed and explained. Following microscopic identification and separation of target cells from the surrounding tissues using laser cutting, the ECM uses electrostatic forces to capture target cells. Validation experiments indicate that ECM can capture a wide assortment of contamination-free homogeneous samples, ranging from very tiny pieces of a few micrometers in diameter to large pieces with a surface area of over 40,000 µm2. Evidence is also provided indicating that uncontaminated homogeneous tissue materials collected by ECM are suitable for further DNA and RNA analysis. This suggests that ECM capture causes little or no identifiable damage to the collected tissues. This technique has significant advantages compared with existing traditional capture methods, such as very low risk of biological sample damage and the fact that it can be applied to both upright and inverted microscopy. The latter allows for separating target cells in tissue culture. ECM usage provides a cost-effective alternative to more traditional laser capture microdissection techniques.