Temperature Measurement in Microfluidic Systems Using a Temperature-Dependent Fluorescent Dye

TLDR

The study presents a fluorescence‑based technique for measuring fluid temperatures in microfluidic systems. Using a standard fluorescence microscope and CCD camera, the method attains micrometer spatial and millisecond temporal resolution. It accurately maps Joule‑heating temperature distributions, measuring 20–90 °C with 0.03–3.5 °C precision and achieving 1 µm spatial and 33 ms temporal resolution.

Abstract

A technique is described for the measurement of fluid temperatures in microfluidic systems based on temperature-dependent fluorescence. The technique is easy to implement with a standard fluorescence microscope and CCD camera. In addition, the method can be used to measure fluid temperatures with micrometer spatial resolution and millisecond time resolution. The efficacy of the method is demonstrated by measuring temperature distributions resulting from Joule heating in a variety of microfluidic circuits that are electrokinetically pumped. With the equipment used for these measurements, fluid temperatures ranging from room temperature to 90 degrees C were measured with a precision ranging from 0.03 to 3.5 degrees C-dependent on the amount of signal averaging done. The spatial and temporal resolutions achieved were 1 microm and 33 ms, respectively.