Modeling of integrated nanoneedle-microfluidic system for single cell temperature measurement

Abstract

In this research, a finite element study on a nanoneedle-microfluidic system for single cell temperature measurement is presented. The nanoneedle design and electrical and mechanical characterization are analyzed, in which tungsten is used as the sensing material. A rectangular shaped sensor with a gap of 10.8 μm showed to give the same current density distribution within the nanoneedle, and a 90 nm2 cross-sectional area showed to cause minimum damage to the cell. Furthermore, the current showed to have a positive temperature coefficient of resistance (TCR) with an increase in the temperature, and the nanoneedle showed to be able to resist ramp force up to 22.5 μN before failure. Electrical measurement on yeast cell showed that the nanoneedle was independent of the cell conductivity. The nanoneedle proved to be able to measure temperature with a current difference of 50 nA and a resolution of 0.02 °C in 10 ms. A Y-shaped microchannel was proposed and the microchannel cross-sectional area was optimized to be 63 μm2 and a flow rate of 24.6 pL/min allowed successful cell penetration causing minimal damage to the cell.