On-chip pressure measurements and channel deformation after oil absorption

Hunter, L., Gala de Pablo, J., Stammers, A. C. , Thomson, N. H., Evans, S. D. and Shim, J.-u. (2020) On-chip pressure measurements and channel deformation after oil absorption. SN Applied Sciences, 2(9), 1501. (doi: 10.1007/s42452-020-03288-8)

Abstract

Microfluidic channels moulded from the soft polymer poly(dimethylsiloxane) (PDMS) are widely used as a platform for mimicking biological environments, and can be used for the simulation of fluid filled structures such as blood and lung vessels. The control of pressure and flow rate within these structures is vital to mimic physiological conditions. The flexibility of PDMS leads to pressure-induced deformation under flow, leading to variable flow profiles along a device. Here, we investigate the change in Young’s modulus of microfluidic channels due to infiltration of mineral oil, a PDMS permeable fluid, and how this affects the resulting pressure profile using a novel pressure measurement method. We found a 53% decrease in Young’s modulus of PDMS due to mineral oil absorption over the course of 3 h accounted for lower internal pressure and larger channel deformation compared to fresh PDMS at a given flow rate. Confocal fluorescence microscopy used to image channel profiles before and after the introduction of mineral oil showed a change in pressure-induced deformation after infiltration of the oil. Atomic force microscopy (AFM) nanoindentation was used to measure Young’s modulus of PDMS before (2.80±0.03 MPa) and after (1.32±0.04 MPa) mineral oil absorption. Raman spectroscopy showed the infiltration of mineral oil into PDMS from channel walls and revealed the diffusion coefficient of mineral oil in PDMS.

• Item Type: Articles
• Additional Information: The authors acknowledge the financial support of the Engineering and Physical Sciences Research Council (Grant No. EP/M506552/1).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Stammers, Dr Ashley
• Authors: Hunter, L., Gala de Pablo, J., Stammers, A. C., Thomson, N. H., Evans, S. D., and Shim, J.-u.
• College/School: College of Science and Engineering > School of Engineering > Biomedical Engineering
• Journal Name: SN Applied Sciences
• Publisher: Springer
• ISSN: 2523-3963
• ISSN (Online): 2523-3971
• Copyright Holders: Copyright © 2020 The Authors
• First Published: First published in SN Applied Sciences 2(9):1501
• Publisher Policy: Reproduced under a Creative Commons License