EWOD driven cleaning of bioparticles on hydrophobic and superhydrophobic surfaces

Abstract

Environmental air monitoring is of great interest due to the large number of people concerned and exposed to different possible risks. From the most common particles in our environment (e.g. by-products of combustion or pollens) to more specific and dangerous agents (e.g. pathogenic micro-organisms), there are a large range of particles that need to be controlled. In this article we propose an original study on the collection of electrostatically deposited particles using electrowetting droplet displacement. A variety of particles were studied, from synthetic particles (e.g. Polystyrene Latex (PSL) microsphere) to different classes of biological particle (proteins, bacterial spores and a viral simulant). Furthermore, we have compared ElectroWetting-On-Dielectric (EWOD) collecting efficiency using either a hydrophobic or a superhydrophobic counter electrode. We observe different cleaning efficiencies, depending on the hydrophobicity of the substrate (varying from 45% to 99%). Superhydrophobic surfaces show the best cleaning efficiency with water droplets for all investigated particles (MS2 bacteriophage, BG (Bacillus atrophaeus) spores, OA (ovalbumin) proteins, and PSL).

Bio-Inspired Extreme Wetting Surfaces for Biomedical Applications

“…Open-channel droplet-based microfluidic systems have several benefits compared with conventional closed-channel based microfluidic devices in terms of easy introduction of sample liquid, low sample and energy consumptions, and rapid chemical and biological reactions [155,156,157,158,159,160,161,162,163,164,165]. Manipulation of droplet motions is most important for the open-channel droplet-based microfluidic system.…”

A high-efficiency superhydrophobic plasma separator

“…These surfaces are self-cleaning, that is, water droplets can roll off these surfaces at a very small tilt angle and carry away dust particles and debris. 34,35 Superhydrophobic coatings have been applied to surfaces to repel bioparticles due to their excellent anti-adhesion and anti-biofouling properties. 36,37 In recent years, there has been an increasing interest in incorporating superhydrophobic surfaces into microfluidic devices for fluid manipulation 38,39 and bioanalytical applications.…”

Digital Microfluidic Processing of Mammalian Embryos for Vitrification

“…Serum contains a mixture of proteins that can adsorb on the Teflon coated surfaces of the device, eventually accumulating to the point that the surface becomes hydrophilic, making droplets immovable [38]. Some strategies have been developed to help overcome this problem, such as the use of Pluronic additives [39], silicone oil baths [40], and superhydrophobic surfaces [41]. Pluronic additives were avoided in our work as embryos are highly sensitive to additives.…”