A disposable on-chip phosphate sensor with planar cobalt microelectrodes on polymer substrate.
Disposable microsensors on polymer substrates consisting of fully integrated on-chip planar cobalt (Co) microelectrodes, Ag/AgCl reference electrodes, and microfluidic channels have been designed, fabricated, and characterized for phosphate concentration measurement in aqueous solution. The planar Co microelectrode shows phosphate-selective potential response over the range from 10(-5) to 10(-2)M in acidic medium (pH 5.0) for both inorganic (KH(2)PO(4)) and organic (adenosine 5'-triphosphate (ATP) and adenosine 5'-diphosphates (ADP)) phosphate compounds. This microfabricated sensor also demonstrates significant reproducibility with a small repeated sensing deviation (i.e. relative standard deviation (R.S.D.)<1%) on a single chip and a small chip-to-chip deviation (i.e. R.S.D.<2.5%). Specifically, while keeping the high selectivity, sensitivity, and stability of a conventional bulk Co-wire electrode, the proposed phosphate sensor yields advantages such as ease of use, cost effectiveness, reduced analyte consumption, and ease of integrating into disposable polymer lab-on-a-chip devices. The capability to sense both inorganic and organic phosphate compounds makes this sensor applicable in diverse areas such as environmental monitoring, soil extract analysis, and clinical diagnostics.
Zou
Zhiwei
Z
Microsystems and BioMEMS Laboratory, Department of Electrical and Computer Engineering, University of Cincinnati, Cincinnati, OH 45221-0030, USA. zouz@ececs.uc.edu
Han
Jungyoup
J
Jang
Am
A
Bishop
Paul L
PL
Ahn
Chong H
CH
D015374:Biosensing Techniques / Q000295:instrumentation*; D003035:Cobalt; D056656:Lab-On-A-Chip Devices; D008839:Microelectrodes; D010710:Phosphates / Q000032:analysis*; D011108:Polymers; D017680:Potassium Compounds / Q000032:analysis*
D010710:Phosphates; D011108:Polymers; D017680:Potassium Compounds; D003035:Cobalt; C013216:potassium phosphate