Fast thermo-pneumatic actuation of a thin PDMS membrane using a micro Peltier-element for microfluidic applications

Abstract

In this paper we present a concept for fast thermo-pneumatic actuation of a thin flexible PDMS membrane using a micro Peltier-element for controlling the temperature of the working fluid in a piston-like liquid reservoir. By adjusting the temperature of the working fluid, in our case ethanol, the volumetric thermal expansion is controlled, which is in turn directly coupled to membrane deflection. Pinch-off and subsequent release of a microfluidic channel above the membrane is achieved in a few seconds. The proposed setup can be potentially utilized for the realization of fast and robust microfluidic valves and pumps.Schnelle thermopneumatische Aktuation einer dü nnen PDMS-Membran mittels Mikro-Peltier-Elements fü r mikrofluidische Anwendungen.In diesem Beitrag wird ein Konzept fü r eine schnelle thermopneumatische Aktuation einer dü nnen, flexiblen PDMS-Membran vorgestellt. Dabei wird die Temperatur einer Arbeitsflü ssigkeit in einem kolbenä hnlichen Flü ssigkeitsreservoir mittels eines Mikro-Peltier-Elements gesteuert. Durch Variation der Temperatur der Arbeitsflü ssigkeit, in diesem Fall Ethanol, wird ü ber die volumetrische thermische Ausdehnung direkt eine Auslenkung der Membran erzielt. Das Abschnü ren und anschließende Ö ffnen eines mikrofluidischen Kanals oberhalb der Membran benö tigt nur wenige Sekunden. Das vorgestellte Setup kann fü r die Realisierung von schnellen und robusten mikrofluidischen Ventilen und Pumpen benutzt werden.Schlü sselwö rter: PDMS-Membran; Mikro-Peltier-Element; Arbeitsflü ssigkeit; thermische Ausdehnung

Disposable DNA Amplification Chips with Integrated Low-Cost Heaters †

“…Miniaturizing heaters lowers the bulkiness and power consumption. Miniaturized heaters can be integrated as integrated resistive heaters, e.g., as deposited thin-film metal [26][27][28][29] or as laminated Cu foil [30], or as micro-Peltier elements [31,32]. These miniaturized heaters can be implemented directly onto the microfluidic chip [28] or on a different substrate and leter incorporated onto the microfluidic chip [33][34][35][36].…”

“…This biocompatibility can be an intrinsic property of the material or the surface can be modified or coated to achieve this [12][13][14][15][16][17][18][19][20]. One often used material is polydimethylsiloxane (PDMS) [22,23,31,32,34,35,38], which can be processed using soft lithography [39]. However, this is a fabrication technology used in academia and is not suitable for upscaling to mass production [40].…”

Development of a Low-Cost, Wireless Smart Thermostat for Isothermal DNA Amplification in Lab-On-A-Chip Devices

“…Heating elements used in LoC are typically electrical, with two main categories: external Peltier [11,12,13,14] and integrated resistive [15,16,17] or micro-Peltier [18,19,20]. All of these are regulated by thermostats that are typically external to the LoC device.…”