Selective electrohydrodynamic concentration of waterborne parasites on a chip. Issue 21 (4th October 2018)

• Record Type: Journal Article
• Authors: Lejard-Malki, Romuald; Follet, Jérôme; Vlandas, Alexis; Senez, Vincent
• Is Part Of: Lab on a chip. Volume 18:Issue 21(2018)
• Page Start: 3310
• Page End: 3322
• Publication Date: 2018-10-04
• Subjects: Miniature electronic equipment -- Periodicals; Combinatorial chemistry -- Periodicals; Biotechnology -- Periodicals; 543.0813
• DOI: 10.1039/c8lc00840j
• Languages: English
• ISSNs: 1473-0197

Abstract

Abstract : Coupling electrohydrodynamic forces and electrowetting-on-dielectric actuation allows concentration of diluted biological samples in 10 μL droplets. Abstract : Concentrating diluted samples is a key step to improve detection capabilities. The wise use of scaling laws shows the advantages of working with sub-microliter-sized samples. Rapid progress in MEMS technologies has driven the design of integrated platforms performing many biochemical operations. Here we report a new concentrator device based on electro-hydrodynamic forces which can be easily integrated into electrowetting-on-dielectric (EWOD) platforms. This approach is label-free and applicable to a wide range of micro-objects. The detection and analysis of two common waterborne parasites, Cryptosporidium and Giardia, is a perfect test case due to their global health relevance. By fully controlling the interplay of the various forces acting on the micron-sized Cryptosporidium parvum and Cryptosporidium muris oocysts, we show that it is possible to concentrate them on the side of a 10 μL initial drop and then extract them efficiently from a droplet of a few hundred nanoliters. We performed a finite element modeling of the forces acting on the parasites' oocysts to optimize the electrodes' shapes. We obtained state-of-the-art concentration factors of 12 ± 0.4 times and 2 to 4 times in the sub-region of the drop and the extracted droplet, respectively, with an efficiency of 70 ± 6%. Furthermore, this device had the ability to selectively concentrate parasites of different species out of a mix. We demonstrated this by segregating C. parvum oocysts from either Giardia lamblia cysts or its related species, C. muris oocysts.