title: A disposable on-chip phosphate sensor with planar cobalt microelectrodes on polymer substrate.
abstract: 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.
authors.affiliation: Microsystems and BioMEMS Laboratory, Department of Electrical and Computer Engineering, University of Cincinnati, Cincinnati, OH 45221-0030, USA. zouz@ececs.uc.edu
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Zou
authors.forename: Jungyoup
authors.initials: J
authors.lastname: Han
authors.forename: Am
authors.initials: A
authors.lastname: Jang
authors.forename: Paul L
authors.initials: PL
authors.lastname: Bishop
authors.forename: Chong H
authors.initials: CH
authors.lastname: Ahn
mesh_terms: 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*
chemical_list: D010710:Phosphates; D011108:Polymers; D017680:Potassium Compounds; D003035:Cobalt; C013216:potassium phosphate