Electrolysis of selectively patterned Vorticella with pneumatic microchambers and electrodes

Abstract

Living machines are expected to expand the limits of silicon microtechnology. Vorticella convallaria is a ciliated protozoa and a promising linear actuator. The use of Vorticella as a Ca2+-responsive actuator, in a small system, requires a reduction in the size of the membrane treatment of selectively patterned Vorticella. However, selective cell patterning and the electrolysis of cell membranes have not yet been combined; therefore, the development of a combined method is essential. The objective of this study is to develop a method for combining selective cell patterning and the electrolysis of cell membranes. A two-layer pneumatic device was fabricated in polydimethylsiloxane (PDMS), and the device and electrodes were clamped with acrylic plates. The deformation of the PDMS membrane was controlled by compressed air. The electrochemical reactions were visualized with fluorescein, and the temporal pH change was evaluated. Vorticella cells were introduced into a microfluidic device and were captured in chambers at a pressure of 21 kPa. They were immobilized in the chambers after incubation for 6 h. Further, OH– was generated from the cathode by the electrolysis of water, and the bell-shaped bodies of Vorticella became spherical. This permeabilization treatment stopped both spontaneous contraction and cilia movement. The application of DC 3 V was sufficient for the electrolysis of Vorticella. Selective patterning and electrochemical membrane treatments are beneficial for facilitating the use of Vorticella as a Ca2+ responsive actuator in a small system.

Keywords

• selective patterning
• electrochemical treatment
• bioactuator
• pneumatic channel
• vorticella
• permeabilization