Indirect micromanipulation of microorganism with gel micro-bead for monitoring in the permeation cage on a chip

We developed a novel, technique to investigate individual properties of microorganisms on a chip using in-situ microfabrication of gel micro-bead and permeation membrane. We propose in-situ formation of gel micro-bead made of the thermoreversible hydrogel for indirect laser micromanipulation of microorganism. Irradiation of a 1064 nm laser to the aqueous solution mixed with poly-(N-isopropylacrylamide) through a high magnification lens resulted in formation of the gel micro-bead at the laser focus by heating. This paper shows a method to reduce the laser power to make a gel micro-bead using the poly-(N-isopropylacrylamide) aqueous solution by adding the additives. We selected YPD Broth as an additive and measured the relationship between the laser power, irradiation time, and diameter of the gel micro-bead. We succeeded in reducing the laser power for gel micro-bead formation, and succeeded in transportation of a yeast cell to the cell cage and manipulation of DNA. The cage having vertical permeation membrane was fabricated in situ in the microchannel by providing the photo-crosslinkable resin and curing it in situ by the focused UV irradiation. Since the cage is made of the permeable membrane, we can culture the cells in it and observe their chemical reactions microscopically by providing growth media or reagents. In experiment, we confirmed repeatability of on-demand analysis of isolated individual yeast cells