title: Development and characterization of an all-solid-state potentiometric biosensor array microfluidic device for multiple ion analysis.
abstract: A microfluidic device with an all-solid-state potentiometric biosensor array was developed using microfabrication technology. The sensor array included a pH indicator, and potassium and calcium ion-selective microelectrodes. The pH indicator was an iridium oxide thin film modified platinum microelectrode and the iridium oxide was deposited by an electrochemical method. The potassium and calcium ion-selective microelectrodes were platinum coated with silicon rubber based ion-selective membranes with respectively potassium (valinomycin) and calcium (ETH 1001) ionophores. The detection system was integrated with a micro-pneumatic pump which can continuously drive fluids into the microchannel through sensors at flow rates ranging from 52.4 microl min(-1) to 7.67 microl min(-1). The sensor array microfluidic device showed near-Nernstian responses with slopes of 62.62 mV +/- 2.5 mV pH(-1), 53.76 mV +/- 3 mV -log[K+](-1) and 25.77 mV +/- 2 mV -log[Ca2+](-1) at 25 degrees C +/- 5 degrees C, and a linear response within the pH range of 2-10, with potassium and calcium concentrations between 0.1 M and 10(-6) M. In this study the device provided a convenient way to measure the concentration of hydrogen, potassium and calcium ions, which are important physiological parameters.
authors.affiliation: Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Wei-Yin
authors.initials: WY
authors.lastname: Liao
authors.forename: Chen-Hsun
authors.initials: CH
authors.lastname: Weng
authors.forename: Gwo-Bin
authors.initials: GB
authors.lastname: Lee
authors.forename: Tse-Chuan
authors.initials: TC
authors.lastname: Chou
mesh_terms: D015374:Biosensing Techniques; D002118:Calcium / Q000032:analysis*; D003959:Diamines / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D008839:Microelectrodes; D046210:Microfluidic Analytical Techniques; D011188:Potassium / Q000032:analysis*; D011199:Potentiometry; D014634:Valinomycin / Q000737:chemistry
chemical_list: D003959:Diamines; D008567:Membranes, Artificial; D014634:Valinomycin; C045768:ETH 1001; D011188:Potassium; D002118:Calcium