Regular Article – Soft Matter
Temperature profile characterization with fluorescence lifetime imaging microscopy in a thermophoretic chip
IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428, Jülich, Germany
2 Technische Universität Dresden Center for Molecular and Cellular Bioengineering, D-01062, Dresden, Germany
3 Neuroelectronics, Munich School of Bioengineering, Department of Electrical and Computer Engineering, Technical University of Munich, D-85748, Garching bei München, Germany
4 Chemistry Department-Physical Chemistry, University Cologne, D-50939, Cologne, Germany
Accepted: 1 October 2021
Published online: 19 October 2021
This study introduces a thermophoretic lab-on-a-chip device to measure the Soret coefficient. We use resistive heating of a microwire on the chip to induce a temperature gradient, which is measured by fluorescence lifetime imaging microscopy (FLIM). To verify the functionality of the device, we used dyed polystyrene particles with a diameter of 25 nm. A confocal microscope is utilized to monitor the concentration profile of colloidal particles in the temperature field. Based on the measured temperature and concentration differences, we calculate the corresponding Soret coefficient. The same particles have been recently investigated with thermal diffusion forced Rayleigh scattering (TDFRS) and we find that the obtained Soret coefficients agree with literature results. This chip offers a simple way to study the thermophoretic behavior of biological systems in multicomponent buffer solutions quantitatively, which are difficult to study with optical methods solely relying on the refractive index contrast.
© The Author(s) 2021. corrected publication 2021
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