title: Ionophore-containing siloprene membranes: direct comparison between conventional ion-selective electrodes and silicon nanowire-based field-effect transistors.
abstract: Siloprene-based, ion-selective membranes (ISMs) were drop-casted onto a field-effect transistor device that consisted of a single-chip array of top-down prepared silicon nanowires (SiNWs). Within one array, two sets of SiNWs were covered with ISMs, each containing two different ionophores, allowing the simultaneous sensing of K and Na ions using a flow cell. It is shown that both ions can be effectively detected in the same solution over a wide concentration range from 10(-4) to 10(-1) M without interference. The ISMs were also analyzed in a conventional ISE configuration, allowing a direct comparison. While the responses for K(+) were similar for both sensor configurations, remarkably, the Na(+) response of the ISM-covered SiNW device was found to be higher than the one of the ISE configuration. The addition of a Na(+) buffering hydrogel layer between the SiO2 of the SiNW and the ISM reduced the response, showing the importance of keeping the boundary potential at the SiO2/ISM interface constant. The responses of the siloprene-covered SiNW devices were found to be stable over a period of at least 6 weeks, showing their potential as a multichannel sensor device.
authors.affiliation: Department of Chemical Engineering, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands.
authors.forename: Anping
authors.initials: A
authors.lastname: Cao
authors.forename: Marleen
authors.initials: M
authors.lastname: Mescher
authors.forename: Duco
authors.initials: D
authors.lastname: Bosma
authors.forename: Johan H
authors.initials: JH
authors.lastname: Klootwijk
authors.forename: Ernst J R
authors.initials: EJ
authors.lastname: Sudhölter
authors.forename: Louis C P M
authors.initials: LC
authors.lastname: de Smet
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D017736:Ion-Selective Electrodes; D007476:Ionophores / Q000737:chemistry*; D008567:Membranes, Artificial; D036103:Nanotechnology / Q000379:methods*; D053770:Nanowires / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011143:Polyvinyl Chloride / Q000737:chemistry; D011188:Potassium / Q000737:chemistry / Q000378:metabolism; D012825:Silicon / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D012964:Sodium / Q000737:chemistry / Q000378:metabolism; D014173:Transistors, Electronic
chemical_list: D007476:Ionophores; D008567:Membranes, Artificial; D011108:Polymers; D012822:Silicon Dioxide; D011143:Polyvinyl Chloride; D012964:Sodium; D011188:Potassium; D012825:Silicon