Atomic force microscopy based nanorobotic operations for biomedical investigations

Atomic Force Microscopy (AFM) based nanorobotics has been applied for building nano devices for almost a decade. It also offers the prospect for analyzing, handling and manipulating biological objects at nanometer scale. AFM itself is a high resolution imaging tool with unique advantages over others to work in liquid where physiological conditions can be maintained for biological samples. Visualization of cytoskeleton structures of live cells was done through controlling the interaction force of the AFM tip with the live cell membrane at nN or sub-nN range. More importantly, by considering the AFM cantilever as a robotic arm with capabilities of mechanical pulling, pushing and cutting, the nanoscale handling and manipulation can be achieved. Utilizing its localization ability, mechanical property characterization can be performed on a great number of cells. Stiffness change is observed by statistically analyzing the Young's modulus values of individual B lymphoma cells before and after antibody treatment. With precise motion planning and control, nano-dissection can be realized on individual or bundles of cytoskeleton elements at sub-100 nm cuts. This was demonstrated by the dissection of intermediate filaments connecting neighboring human keratinocytes. These biomedical investigations with the aid of AFM based nanorobotics can facilitate the search for biomarkers in disease diagnosis and treatment and the understanding of dynamic signaling events of cell biology.