A radio frequency controlled microvalve for biomedical applications

Abstract

In this paper we propose the use of a RF controlled microvalve for implementation on a PZT substrate for biomedical applications. Such device has a huge range of applications such as parallel mixing of photo-lithographically defined nanolitre volumes, flow control in pneumatically driven microfluidic systems and lab-on-chip applications. The microvalve makes use of direct actuation mechanisms at the microscale level to allow its use in vivo applications. A number of acoustic propagation modes are investigated and their suitability for biomedical applications, in terms of the required displacement, device size and operation frequency. A theoretical model of the Surface Acoustic Wave (SAW) device is presented and its use in micro-valve application was evaluated using ANSYS tools. Furthermore, the wireless aspect of the device is considered through combining the RF antenna with the microvalve simulation by assuming a high carrier frequency with a small peak-to-peak signal. A new microvalve structure which uses a parallel type piezoelectric bimorph actuator was designed and simulated using ANSYS tools. Then, further optimization of the device was carried out to achieve a better coupling between electrical signal and mechanical actuation within the SAW device.

Recent advances in microscale pumping technologies: a review and evaluation

“…Hence, the flow becomes directional. Cantilever structures (similar to those in Figure 2) are also commonly used as valve structures and have been shown to be amenable to active control using piezoelectric and RF modulation (Dissanayake et al 2007). …”

Surface acoustic wave device based wireless passive microvalve for microfluidic applications

“…The main PSicmapurap Displacement AmSlySie actuation mechanisms are piezoelectric actuation, electrostatic actuation, electromagnetic actuation, pneumatic actuation, Shape Memory Alloy (SMA) actuation, thermo-pneumatic actuation and bimetallic actuation. 13 Of these mechanisms, piezoelectric actuators are known for low power consumption and high force generation, 14 though the actuation displacement is comparatively lesser and fabrication requirements are fairly complex. Whereas electrostatic actuators generate a comparatively faster response time and shows a good reliability, even though the small force generated and comparatively smaller stroke are not attractive.…”

Design and characterisation of micro-diaphragm for low power drug delivery applications

“…1 Based on the previous work carried out by the authors 1,3,4 it is been demonstrated that the required wireless and batteryless actuation for a microfluidic device is achievable using a fully passive system. Initially, the micropump structure is designed by integrating a SAW device and a micropump chamber, which causes the microfluidic modulation.…”