In-Situ Formation of a Gel Microbead for Laser Micromanipulation of Microorganisms, DNA, and Viruses

Abstract

We proposein situformation of gel microbeads made of a thermoreversible hydrogel for indirect laser micromanipulation of microorganisms, DNA, and viruses. Using a 1064 nm laser, we irradiated an aqueous solution mixed with poly-(N-isopropylacrylamide) through a high- magnification lens, thereby forming a gel microbead through heating at the laser focus. The gel microbead, trapped by the laser, was used to indirectly manipulate micro- and nano-scale samples. Laser tweezers stably handle micro-scale object ranging from several tens of nm to several hundreds of µm. This cannot be done with nano-scale objects of a few nm, however, due to laser beam heating. We demonstrate how to manipulate microorganisms, DNA, and viruses indirectly using a gel microbead made from an aqueous poly-(N-isopropylacrylamide) solution. We reduced laser power for gel microbead formation, and used the gel microbead trapped by the laser to manipulate microorganisms, DNA, and viruses.