Electron beam induced fine virtual electrode for mechanical strain microscopy of living cell

摘要

We have demonstrated nanomechanical applications using physicochemical and electrochemical phenomena of inverted-electron beam lithography (I-EBL), which induced in-situ two-dimensional (2-D) processing on wet samples and a living cell after the EB was stoppted in a 100-nm thick SiN membrane. The incident EB generates a virtual electrode and then this induces electrochemical and electrokinetic phenomena around the scanning trajectory. The I-EBL processing has a 120-nm resolution in full-width-at-half-maximum (FWHM) at the deposited line-and-space pattern in 10mM 3,4-ethylenedioxythiophene (EDOT) diluted water solution. The virtual electrode also causes a electrokinetic local repulsive force with ＜ ～ 1 μm resolution toward the negatively charged nanoparticles, and the 2-D scanning of the EB allows 2-D actuation of the nanoparticles dispersed in a pure water solution. The virtual electrode also induces local detachment of adherent nanoparticles and focal adhesion of a living cell from the SiN membrane in a saline solution, probably due to both electrokinetic and partly chemical protein denaturation processes. The local detachment of a living cell is utilized to investigate spatio-temporal distributions of intracellular elastic strain as mechanical strain microscopy (MSM), which represents mechanical connectivity in the intracellular structure. This MSM should provide visualization of the location of the force generation in the cell.