Selective calcium ion detection with functionalized ZnO nanorods-extended gate MOSFET.
Zinc oxide nanorod-extended gate field effect transistor (MOSFET) is demonstrated for the detection of calcium (Ca(2+)) ions. ZnO nanorods were grown on the surface of a silver wire to produce an electrochemical nanosensor for selectively detecting Ca(2+). The electrochemical response from the interaction between the ZnO nanorods and Ca(2+) in an aqueous solution is coupled directly to the gate of a field effect transistor (MOSFET). The induced voltage change on the gate results in a measureable current response. In order to adapt the sensors for Ca(2+) ions measurements in biological fluids with sufficient selectivity and stability, a plastic membrane coating containing ionophores was applied on the nanorods. The sensor exhibited a linear response within the range of interest from 1 microM to 1 mM. This work demonstrates a simple technique for sensitive detection of Ca(2+) ions by efficient transfer of the chemical response directly to a standard electronic component producing a low impedance signal.
Department of Science and Technology (ITN), Campus Norrköping, Linköping University, Norrköping, Sweden. muhas@itn.liu.se
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D015374:Biosensing Techniques / Q000295:instrumentation*; D002118:Calcium / Q000032:analysis*; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007477:Ions; D036103:Nanotechnology / Q000295:instrumentation*; D043942:Nanotubes / Q000737:chemistry*; D012680:Sensitivity and Specificity; D014173:Transistors, Electronic; D015034:Zinc Oxide / Q000737:chemistry*
D007477:Ions; D015034:Zinc Oxide; D002118:Calcium