Biosensors (May 2016)

Implementing Silicon Nanoribbon Field-Effect Transistors as Arrays for Multiple Ion Detection

  • Ralph L. Stoop,
  • Mathias Wipf,
  • Steffen Müller,
  • Kristine Bedner,
  • Iain A. Wright,
  • Colin J. Martin,
  • Edwin C. Constable,
  • Axel Fanget,
  • Christian Schönenberger,
  • Michel Calame

DOI
https://doi.org/10.3390/bios6020021
Journal volume & issue
Vol. 6, no. 2
p. 21

Abstract

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Ionic gradients play a crucial role in the physiology of the human body, ranging from metabolism in cells to muscle contractions or brain activities. To monitor these ions, inexpensive, label-free chemical sensing devices are needed. Field-effect transistors (FETs) based on silicon (Si) nanowires or nanoribbons (NRs) have a great potential as future biochemical sensors as they allow for the integration in microscopic devices at low production costs. Integrating NRs in dense arrays on a single chip expands the field of applications to implantable electrodes or multifunctional chemical sensing platforms. Ideally, such a platform is capable of detecting numerous species in a complex analyte. Here, we demonstrate the basis for simultaneous sodium and fluoride ion detection with a single sensor chip consisting of arrays of gold-coated SiNR FETs. A microfluidic system with individual channels allows modifying the NR surfaces with self-assembled monolayers of two types of ion receptors sensitive to sodium and fluoride ions. The functionalization procedure results in a differential setup having active fluoride- and sodium-sensitive NRs together with bare gold control NRs on the same chip. Comparing functionalized NRs with control NRs allows the compensation of non-specific contributions from changes in the background electrolyte concentration and reveals the response to the targeted species.

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