Development and Biological Application of Nanodynamics Observation System(BIXAM) by Tip-scan Atomic Force Microscopy

Cellular morphological changes and molecular dynamics are observed using microscopes, facilitating biological discoveries and explaining biological functions. Our hybrid atomic force microscopy (AFM)-optical microscopy system enables observation of dynamics at higher resolution than the diffraction-limit of optical microscopes. The system requires compatibility between the fluorescent microscope function, which discriminates among molecular samples, and the AFM function for observation of dynamics with minimal sample impact. The AFM configuration for compatibility of both microscope functions is a probe scan (tip-scan). High-speed, less-invasive stable control is essential for observing sample dynamics. High-speed requires a cantilever with high resonance frequency and a high-speed scanning mechanism. Less invasiveness (reduced sample deformation) requires a small cantilever with small spring constant and small inertial mass. Stability requires a high-precision light-tracking displacement sensor. Our Nanodynamics observation system (BIXAM) satisfies these requirements and enables simultaneous observation of fluorescent microscopic and AFM images of protein molecule localization under the cell membrane in living cells. Here we present the system and observation examples.