Numerically Controlled Electrochemical Etching of Tungsten Nano-needles for Penetrating the Tough Yeast Cell Wall

Abstract

Effectively transferring foreign macromolecule into yeast cells has been challenging for decades due to the tough yeast cell wall. The existing transfer methods require removing the cell wall or changing the cell wall permeability, which seriously damages the cell structure and affects their further budding proliferation. Traditional microinjection is successfully applied to animal cells but not viable for yeast cells due to the low stiffness of glass micro-pipette tip compared to the tough yeast cell wall. In this paper, a tungsten nano-needle with optimized tip profile is fabricated via a numerically controlled electrochemical etching platform. We successfully penetrated the tough yeast cell wall by using our customized tungsten nano-needle. The experiment results confirm the possibility of mechanically penetrating the yeast cell wall by nano-needles. This method may start a new promising way for further microinjection of foreign substances into yeast cells.