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Integrated Electrochemical Analysis System with Microfluidic and Sensing Functions
Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
* Author to whom correspondence should be addressed.
Received: 17 January 2008; Accepted: 18 February 2008 / Published: 21 February 2008
Abstract: An integrated device that carries out the timely transport of solutions andconducts electroanalysis was constructed. The transport of solutions was based oncapillary action in overall hydrophilic flow channels and control by valves that operateon the basis of electrowetting. Electrochemical sensors including glucose, lactate,glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), pH,ammonia, urea, and creatinine were integrated. An air gap structure was used for theammonia, urea, and creatinine sensors to realize a rapid response. To enhance thetransport of ammonia that existed or was produced by the enzymatic reactions, the pHof the solution was elevated by mixing it with a NaOH solution using a valve based onelectrowetting. The sensors for GOT and GPT used a freeze-dried substrate matrix torealize rapid mixing. The sample solution was transported to required sensing sites atdesired times. The integrated sensors showed distinct responses when a sample solutionreached the respective sensing sites. Linear relationships were observed between theoutput signals and the concentration or the logarithm of the concentration of theanalytes. An interferent, L-ascorbic acid, could be eliminated electrochemically in thesample injection port.
Keywords: Flow channel; valve; electrowetting; amperometric sensors; potentiometric sensors
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Satoh, W.; Hosono, H.; Yokomaku, H.; Morimoto, K.; Upadhyay, S.; Suzuki, H. Integrated Electrochemical Analysis System with Microfluidic and Sensing Functions. Sensors 2008, 8, 1111-1127.
Satoh W, Hosono H, Yokomaku H, Morimoto K, Upadhyay S, Suzuki H. Integrated Electrochemical Analysis System with Microfluidic and Sensing Functions. Sensors. 2008; 8(2):1111-1127.
Satoh, Wataru; Hosono, Hiroki; Yokomaku, Hiroomi; Morimoto, Katsuya; Upadhyay, Sanjay; Suzuki, Hiroaki. 2008. "Integrated Electrochemical Analysis System with Microfluidic and Sensing Functions." Sensors 8, no. 2: 1111-1127.