Thermally-actuated microfluidic membrane valve for point-of-care applications

Abstract

Microfluidics has enabled low volume biochemistry reactions to be carried out at the point-of-care. A key component in microfluidics is the microfluidic valve. Microfluidic valves are not only useful for directing flow at intersections but also allow mixtures/dilutions to be tuned real-time and even provide peristaltic pumping capabilities. In the transition from chip-in-a-lab to lab-on-a-chip, it is essential to ensure that microfluidic valves are designed to require less peripheral equipment and that they are transportable. In this paper, a thermally-actuated microfluidic valve is presented. The valve itself is fabricated with off-the-shelf components without the need for sophisticated cleanroom techniques. It is shown that multiple valves can be controlled and operated via a power supply and an Arduino microcontroller; an important step towards transportable microfluidic devices capable of carrying out analytical assays at the point-of-care. It is been calculated that a single actuator costs less than $1, this highlights the potential of the presented valve for scaling out. The valve operation is demonstrated by adjusting the ratio of a water/dye mixture in a continuous flow microfluidic chip with Y-junction channel geometry. The power required to operate one microfluidic valve has been characterised both theoretically and experimentally. Cyclical operation of the valve has been demonstrated for 65 h with 585 actuations. The presented valve is capable of actuating rectangular microfluidic channels of 500 μm × 50 μm with an expected temperature increase of up to 5 °C. The fastest actuation times achieved were 2 s for valve closing (heating) and 9 s for valve opening (cooling).

Open and closed microfluidics for biosensing

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Neuropathogenesis-on-chips for neurodegenerative diseases

“…These features effectively manipulate neurite growth and can create both indirect and direct as well as asymmetric and symmetric neuronal connections. Moreover, valves can be established on the chip to act as a controllable barrier between compartments using external factors, such as air, oil, gel, liquid, temperature, or pressure 447 – 449 . Regulated fluid flow can be achieved using extra pump systems and passive hydrostatic pressure, which applies controllable shear stress to the cells.…”

Microvalves for Applications in Centrifugal Microfluidics

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