Topic No. 5.07 Abstract Reference No: 0279 Oral (Confirmation No. from Website) LOCALIZED EXPRESSION OF HEAT SHOCK PROTEIN IN CELL POPULATION BY MICRO HEATER DEVICE

This paper reports on the localized expression of heat shock proteins (HSPs) in a cell population on a micron-scale. Thermal stimulation was realized by micro heaters on cells in microfluidic channels to investigate cell-cell interactions with precise temperature control of microfluidic channels utilizing temperature sensors. Cell-cell interactions are considered as key factors in tissue and organ formation in vivo. Recently, some researchers locally stimulated cells using microfluidic devices and studied cell-cell interactions [1]. One of the most significant challenges in generating local stimulation is the precise confinement of the stimulants in microfluidic channels due to diffusion and flows. Our group has shown thermal stimulation on single cell level using micro heaters and observed heat shock responses (HSRs) [2]. Here, we present a micro heater device integrated with a microfluidic channel to control a temperature distribution locally on the cell culture medium. Well-controlled temperature distribution was achieved in a micro channel regulating the volume of culture medium and reducing natural convective heat transfer effects. We fabricated the Pt micro heaters and temperature sensors using standard micro-fabrication process on glass substrates. Sensors were designed to measure the temperature from a change in electrical resistance due to high temperature coefficient of resistance (TCR) of Pt. Polydimethylsiloxane (PDMS) microfluidic channels were molded by SU-8 patterns. Finally, the micro heater chip was aligned and bonded to the PDMS micro channels