Open-Surface Microfluidics

J. Berthier, K.A. Brakke, E.P. Furlani, I.H. Karampelas, G. Delapierre
CEA-Leti, FR

Keywords: capillarity, open-surface microfluidics, suspended microfluidics, SCF

Summary:

The developments of open-surface microfluidics (OSM) for biotechnology are recent, and motivated by the development of point-of-care (POC) and home-care systems. The advantages of capillary systems are (1) low cost due to easy and fast fabrication, (2) portability ensured by the capillary actuation of the fluids, (3) user-friendliness due to the simplicity of the device. Open systems bring the additional advantage of accessibility and the facility to eliminate air bubbles. All these aspects contribute to make open capillary systems a preferred choice for POC and home-care systems. We first present the general theory of spontaneous capillary flows (SCF) on textured substrates or between fibers. We shortly present the most popular POC systems presently, i.e. the paper-based systems. Another approach for portable systems is the use of grooves to move the fluid and transport the analytes. We investigate the spontaneous capillary flow (SCF) in micro-grooves. We also investigate a new geometry, that of suspended micro-channels, i.e. where flows use surface tension to fill and maintain a fluid in microscale structures devoid of a ceiling and floor. The SCF onset and dynamics aspects are investigated in all these different geometries; recent applications are reported and analyzed.