Microfluidic Devices Integrating Clinical Alternative Diagnostic Techniques Based on Cell Mechanical Properties
The present paper discusses the development of a microfluidic (lab-on-chip) device to study cells deformability aiming at developing a new diagnostic system for cancer detection. The chip uses electrowetting for droplet transport and cell deformability, on an open configuration. The chip configuration is analyzed towards various steps, from the selection of the materials, to the evaluation of the chip performance. Wetting properties of the selected materials are shown to play a major role. Furthermore, experimental tests confirm the relevance of selecting materials less prone to adsorb the biocomponents, as they tend to locally alter the surface wettability, promoting energy dissipation at the droplet contact line and affecting its manipulation. A rough analysis on droplet evaporation effects suggests that they are not negligible, even at optimum working conditions that minimize the evaporation by mass diffusion (low temperatures and high relative humidity). In this context, exploitation of droplet based microfluidic devices for point-of-care diagnostics in harsh environments should take mass diffusion effects into account.
KeywordsMicrofluidic device Electrowetting Biofluid droplet dynamics Wettability Cancer diagnostics Cell mechanical properties
The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT) for partially financing this research through the project UID/EEA/50009/2013, and for supporting D. Vieira with a fellowship. The work was also partially financed by FCT through the project RECI/EMS-SIS/0147/2012, which also funded the fellowships of F. Mata and J. Pereira. A.S. Moita also acknowledges the contribution of FCT for financing her contract through the IF 2015 recruitment program.
Finally, the authors acknowledge the contribution of Prof. Susana Freitas and her team from INESC-MN for the microfabrication of the test chips.
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