Low-power microfluidic electro-hydraulic pump (EHP)

Abstract

Low-power electrolysis-based microfluidic pumps utilizing the principle of hydraulics, integrated with microfluidic channels in polydimethylsiloxane (PDMS) substrates, are presented. The electro-hydraulic pumps (EHPs), consisting of electrolytic, hydraulic and fluidic chambers, were investigated using two types of electrodes: stainless steel for larger volumes and annealed gold electrodes for smaller-scale devices. Using a hydraulic fluid chamber and a thin flexible PDMS membrane, this novel prototype successfully separates the reagent fluid from the electrolytic fluid, which is particularly important for biological and chemical applications. The hydraulic advantage of the EHP device arises from the precise control of flow rate by changing the electrolytic pressure generated, independent of the volume of the reagent chamber, mimicking the function of a hydraulic press. Since the reservoirs are pre-filled with reagents and sealed prior to testing, external fluid coupling is minimized. The stainless steel electrode EHPs were manufactured with varying chamber volume ratios (1 : 1 to 1 : 3) as a proof-of-concept, and exhibited flow rates of 1.25 to 30 microl/min with electrolysis-based actuation at 2.5 to 10 V(DC). The miniaturized gold electrode EHPs were manufactured with 3 mm diameters and 1 : 1 chamber volume ratios, and produced flow rates of 1.24 to 7.00 microl/min at 2.5 to 10 V(AC), with a higher maximum sustained pressure of 343 KPa, suggesting greater device robustness using methods compatible with microfabrication. The proposed technology is low-cost, low-power and disposable, with a high level of reproducibility, allowing for ease of fabrication and integration into existing microfluidic lab-on-a-chip and analysis systems.

System‐Engineered Miniaturized Robots: From Structure to Intelligence

“…[221] The combination of PDMS-based microfluidic structures and electrochemical effects, such as electrolysis, stands out to be efficient in soft activation. [222,223] The pneumatic force, resulting from gas bubble inflation, has been directly exploited to induce actuation response by an increase in volume of the confinement chambers. [222][223][224] The volumetric actuation technique can be used by any other volume-changing material or device such as microspheres made of magnetically responsive elastomer/ nanoparticle composites.…”

Resettable skin interfaced microfluidic sweat collection devices with chemesthetic hydration feedback

“…Microfluidic systems that combine pumps with soft valves could enable a range of important features, from the ejection of sweat as a mechanism to reset a device to an empty state, to the deployment of wearable time-sensitive assays, such as enzyme-linked immunosorbent assays (ELISA) that involve metered delivery or extraction of fluids. Electrokinetic pumps that exploit electroosmotic 29 and electrolytic 30,31 phenomena and optically driven pumps 32,33 are options, but each requires complex, external control modules. The deformation of elastomeric membranes by pneumatic pressure 34 or manual actuation 35–37 represent attractive alternatives, but they cannot readily generate negative pressure differentials.…”

Fabrication of a 3D Teflon microdevice for energy free homogeneous liquid flow inside a long microchannel and its application to continuous-flow PCR

“…For example, most microuidic devices today require complex and large pumping accessories to achieve sample transport through microchannels. [16][17][18][19] This conicts with the purpose of achieving a convenient and portable process expected from using a microdevice. Even if various selfactivated pumping systems have been applied to microuidic devices, most of these pumps have strict requirements related to the surface tension of the microuidic devices.…”