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

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.

Joule heating and heat transfer in poly(dimethylsiloxane) microfluidic systems

“…3 and Fig. 4 a significant change in the buffer temperature is observed as the two inlet channels converge into the single outlet channel, similar to that observed by Ross et al 20 in acrylic microchannels, due to differences in the rate of internal heat generation in the inlet channels, where both the current and potential field gradient are approximately half that of the mixing channel. It was proposed in that work that such constrictions could be used as a technique for inducing temperature dependent chemical reactions.…”

Joule heating effects on electroosmotic flow in insulator‐based dielectrophoresis

“…They may potentially be harnessed to enhance microfluidic mixing and immunoassay for lab-on-a-chip applications. In future work we plan to make the fluid velocity and temperature measurements using micro particle image velocimetry (mPIV) technique [39] and the rhodamine B-based thermometry techniques [58], respectively. The obtained experimental results will then be compared quantitatively with the predictions of a 3D model that is currently under development in our lab.…”

Temperature response of luminescent tris(bipyridine)ruthenium(II)-doped silica nanoparticles

“…The development of temperature sensors at the micro-and nanoscale has recently received considerable attention due to the growing interest to perform measurements on a variety of unconventional systems, e.g., cells [1,2], lab-on-chip and microfluidic devices [3][4][5]. The different approaches for the design of thermometers at the nanoscale have been reviewed by Lee and Kotov [6].…”

“…Incorporation of rhodamine 6G, acridine orange and [Ru(bpy) 3 ] 2+ into growing SiO 2 particles has already been described in the literature [11][12][13][14][15]. Despite the emission spectra of the aqueous [Ru(bpy) 3 ] 2+ complex, which has a large Stokes fluorescent shift, and decreases linearly with increasing temperature [4], the ability of tris(bipyridine)ruthenium(II)-doped silica nanoparticles (Ru(bpy) 3 @SiO 2 NPs) to sense temperature changes has not yet been reported.…”