Paper Accepted by The Analyst

The following paper was accepted for publication in the Analyst:   T. Walsh, J. Lee, and K. Park,  2015, “Laser-Assisted Photothermal Heating of a Plasmonic Nanoparticle-Suspended Droplet in a Microchannel,” Analyst.   Abstract: The present article reports the numerical and experimental investigations on the laser-assisted photothermal heating of a nanoliter-size droplet in a microchannel when plasmonic particles are suspended in the droplet. Plasmonic nanoparticles exhibit strong light absorption and scattering upon the excitation of localized surface plasmons (LSPs), resulting in intense and rapid photothermal heating in a microchannel. Computational models are implemented to theoretically verify the photothermal behavior of gold nanoshell (GNS) and gold nanorod (GNR) particles suspended in a liquid microdroplet. Experiments were conducted to demonstrate a rapid heating of a sub-100 nL droplet up to 100 °C with high controllability and repeatability. The heating and cooling time to the steady state is in the order of 1 second, while cooling requires less time than heating. The effects of core parameters, such as nanoparticle structure, volumetric concentration, microchannel depth, and laser power density on the heating are studied. The obtained results can be integrated into existing microfluidic technologies that demand accurate and rapid heating of microdroplets in a micro channel.