In situ patterning of organic molecules in aqueous solutions using an inverted electron-beam lithography system

Abstract

A method for in situ controlling the detachment and deposition of organic molecules such as sugars and biocompatible polymers in aqueous solutions by electron-beam (EB) scan is proposed and evaluated. It was demonstrated that EB irradiation could detach 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers from a silicon nitride membrane. Moreover, organic molecules such as cationic polymers and sugars could be deposited on the membrane by EB irradiation. Spatial distributions of scattered electrons were numerically simulated, and acceleration voltage dependences of the detachment and deposition phenomena were experimentally measured. The simulations and experimental results suggest that the detachment of MPC polymers is mainly due to electrical effects of primary electrons, and that the deposition of organic molecules is mainly due to chemical reactions induced by primary electrons. In view of these findings, the proposed method can be applied to in situ and nanoscale patterning such as the fabrication of cell scaffolds.

Multi‐Scale Lipid Membrane Flow by Electron Beam‐Induced Electrowetting

“…According to previous simulations, when the sample was irradiated with a 2.5‐kV EB through the SiN membrane, more than 99% of the electrons were stopped within the membrane. [ 30 ] From the simulations, it was thought possible that these stopped electrons could induce polarization of atoms in the SiN membrane, and inductive electrons at the interface between the membrane and the liquid sample could then be polarized, forming a VC. The lateral size of the VC was about 120 nm, which was estimated from the previous experiment of the line‐and‐space pattern of 3,4‐ethylenedioxythiophene.…”