Micromanipulation system for handling of biological molecule and screening of microbes in a microchannel by electric field and laser tweezers

Abstract

In this paper, we propose a novel methodology on noncontact transportation of DNA molecules by dielectrophoretic force and high throughput screening of microbes. First, we utilize the conformational transition in the higher order structure of DNA for transportation. We designed a simple micro electrode-flow system. Experimental demonstration of DNA transportation in the globule state using dielectrophoretic force and direct observation of the DNA molecule in a non- uniform electric field were carried out with fluorescence microscopy. We discuss the experimental results on the motion of the DNA molecule. We show that transportation of DNA with the state of compacted globule is profitable in the future practical application for the separation of giant DNAs such as human gene. Next, we have developed a prototype of Microchannel system for high throughput screening of Escherichia coli. Experimental demonstration of noncontact transportation and manipulation of Escherichia coli by dielectrophoretic force and radiation pressure of laser tweezers were carried out with laser manipulator system. We discussed the basic strategies to improve the working efficiency and the operability of the micromanipulation and presented a new direction in this field. In experiments, we show that transportation and separation of E. coli cells by dielectrophoretic force and optical trapping is useful for future practical application to the high throughput screening of microbes. We showed the possibility of the Microchannel system as one of the biomanipulation and automation systems for DNA sequencing and pharmaceutical field.