Wirelessly powered electrowetting-on-dielectric (EWOD) by planar receiver coils

Abstract

Electrowetting-on-dielectric (EWOD) is one of the most versatile methods used to control the wettability of liquids using electrical input. In most applications, EWOD is applied using physical wiring, which may restrict its application to implantable EWOD devices. In order to resolve this issue, we have studied and developed a wirelessly powered EWOD by using planar coils at the receiver that are fabricated out of a printed circuit board (PCB) by means of standard micro photolithography. Unlike conventional, bulky, spool coil type, the planar coil type lends itself to compact design and easy integration with EWOD chips. The present wireless powering principle is based on magnetic induction, which is very efficient when the transmitter and receiver coils are close to each other. The voltage obtained at the receiver is much higher than typically required EWOD voltages (>50 V) using a high transmission frequency (~MHz). The span of the EWOD contact angle is over 40°. In addition, amplitude modulation (AM) is implemented in the present wireless powering setup, followed by demodulation, in order to oscillate droplets at low frequency. This technique ensures smooth and reliable droplet movements. The wirelessly powered EWOD is used to transport a droplet and is mounted in a mini-boat which it powers and propels.

Design and characterization of a passive, disposable wireless AC-electroosmotic lab-on-a-film for particle and fluid manipulation

“…Operating at high voltages can have detrimental effects on bioparticle viability and if used improperly, may cause detachment of biomolecules resulting from bioparticle death [61]. Moreover, their functionality is generally limited to only one microfluidic function as in the case of other devices used for particle concentration [30], droplet manipulation [32][33][34][35][36], and fluid pumping [36]. The operational functionality of the LOF presented in this work is truly reconfigurable and its functionality can be externally and wirelessly controlled by adjusting the voltage level Table 1 Comparing characteristic of proposed wireless lab-on-a-film with previously published wireless lab-on-a-chips.…”

“…Recently, the AM scheme has been used for implementation of wireless electrowetting-on-dielectric (EWOD) devices [32][33][34][35]. Byun et al has presented a wireless EWOD device for droplet oscillation and transportation [32,35].…”

Wettability Manipulation by Interface-Localized Liquid Dielectrophoresis: Fundamentals and Applications

“…In the electrowetting mechanism, especially the electrowetting on dielectrics (EWOD) configuration [6,7], the apparent contact angle of a conducting droplet is reversibly modulated by applying a direct current/alternating current (DC/AC) voltage between the droplet and the conducting substrate, separated by a hydrophobic dielectric thin layer. Upon the application of the electric potential across the droplet and the substrate, the free electrical charges (ions) accumulate immediately at the interfaces of the droplets and, as a result, a Coulombic force is developed under the electric field.…”

“…The charge density becomes maximum at the three-phase contact line with the corresponding maximum outward component of the Coulombic force, which pulls the liquid droplet to spread via the deformation of the air–liquid interface. The principle of EWOD was used extensively in various fields [6,8,9,10,11,12,13]. Unlike EWOD, liquid dielectrophoresis (LDEP) does not need any free charges (ions), but requires polarization.…”

Thermal analysis of wirelessly powered thermo-pneumatic micropump based on planar LC circuit

“…This feature was exploited in powering the pumping device using various transmitter-receiver configurations, including spool-type [20,21] and metal disc [22,23] receiver coils. Despite that, they not well suited for transdermal application due to issues related to the bulky devices and not compatible with conventional MEMs fabrication technique [24]. This paper presents a thermal behavior analysis of a thermo-pneumatic micropump that is powered and controlled through RF wireless heating using planar receiver inductive coil.…”