Automating fluid delivery in a capillary microfluidic device using low-voltage electrowetting valves
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A multilayer capillary polymeric microfluidic device integrated with three normally closed electrowetting valves for timed fluidic delivery was developed. The microfluidic channel consisted two flexible layers of poly (ethylene terephthalate) bonded by a pressure-sensitive adhesive spacer tape. Channels were patterned in the spacer tape using laser ablation. Each valve contained two inkjet-printed silver electrodes in series. Capillary flow within the microchannel was stopped at the second electrode which was modified with a hydrophobic monolayer (valve closed). When a potential was applied across the electrodes, the hydrophobic monolayer became hydrophilic and allowed flow to continue (valve opened). The relationship between the actuation voltage, the actuation time, and the distance between two electrodes was performed using a microfluidic chip containing a single microchannel design. The results showed that a low voltage (4.5 V) was able to open the valve within 1 s when the distance between two electrodes was 1 mm. Increased voltages were needed to open the valves when the distance between two electrodes was increased. Additionally, the actuation time required to open the valve increased when voltage was decreased. A multichannel device was fabricated to demonstrate timed fluid delivery between three solutions. Our electrowetting valve system was fabricated using low-cost materials and techniques, can be actuated by a battery, and can be integrated into portable microfluidic devices suitable for point-of-care analysis in resource-limited settings.
KeywordsFlexible microfluidics Electrowetting valve Inkjet printing Lab-on-a-chip Self-assembled monolayer
This project was supported in part by the UMass Amherst Center for Hierarchical Manufacturing, a nanoscience shared facility funded by the National Science Foundation under NSF Grant #CMMI-1025020. The authors thank undergraduate researcher Elsa Zhao for her assistance with silver ink synthesis. The authors would also like to thank S. Brett Walker and Professor Jennifer A. Lewis for assistance with waveform of reactive silver ink.
Supplementary material 1 (MPEG 34012 kb)
- Holmes D, Gawad S (2010) The application of microfluidics in biology. In: Hughes MP, Hoettges KF (eds) Microengineering in Biotechnology. Humana Press, pp 55–80 Google Scholar
- Liedert R, Amundsen LK, Hokkanen A, Maki M, Aittakorpi A, Pakanen M, Scherer JR, Mathies RA, Kurkinen M, Uusitalo S, Hakalahti L, Nevanen TK, Siitari H, Soderlund H (2012) Disposable roll-to-roll hot embossed electrophoresis chip for detection of antibiotic resistance gene mecA in bacteria. Lab Chip 12:333–339CrossRefGoogle Scholar
- Saeki F, Baum J, Moon H, Yoon JY, Kim CJ, Garrell RL (2001) Electrowetting on dielectrics: reducing voltage requirements for microfluidics. Abstr Pap Am Chem Soc 222:8-PMSEGoogle Scholar