Gating Hysteresis as an Indicator for Silicon Nanowire FET Biosensors

Bergoi Ibarlucea,Sebastian Pregl,Lotta Römhildt,Maryam Vahdatzadeh,Gianaurelio Cuniberti,Jörg Opitz,Felix Zörgiebel,Walter Weber,Larysa Baraban,Thomas Mikolajick

doi:10.3390/app8060950

Abstract

We present a biosensor chip with integrated large area silicon nanowire-based field effect transistors (FET) for human α-thrombin detection and propose to implement the hysteresis width of the FET transfer curve as a reliable parameter to quantify the concentration of biomolecules in the solution. We further compare our results to conventional surface potential based measurements and demonstrate that both parameters distinctly respond at a different analyte concentration range. A combination of the two approaches would provide broader possibilities for detecting biomolecules that are present in a sample with highly variable concentrations, or distinct biomolecules that can be found at very different levels. Finally, we qualitatively discuss the physical and chemical origin of the hysteresis signal and associate it with the polarization of thrombin molecules upon binding to the receptor at the nanowire surface.

Highlights

The latest advances in microfluidics and nanotechnology has made possible the transfer of medical diagnostics and health monitoring equipment from the laboratory to the patient’s home [1,2]
This assures the presence of the suitable high performance ion-sensitive field effect transistors (ISFETs) on a chip and would enable the integration in a multiplexing system to verify the reproducibility of the detection events, by measuring simultaneously different devices [45]
We present a thrombin detection platform using large area multiwire field effect transistors (FET) devices, relying on the live monitoring of the transfer curves in the gate sweeping regime. These dynamic sweeping measurements allowed us to observe the occurrence and the further evolution of the transfer curve hysteresis once the thrombin molecules bind to the sensor surface

Summary

Introduction

The latest advances in microfluidics and nanotechnology has made possible the transfer of medical diagnostics and health monitoring equipment from the laboratory to the patient’s home [1,2]. Devices connected by NW arrays are able to deliver a broader dynamic range for the measurements and lower device-to-device variation in current and sensitivity due to the averaging of the different signals coming from the individual wires [36,37] These aspects are critically important for ISFET devices in general and are considered to be typical drawbacks of sensors encompassing individual nanowire channels, in particular. For the first time we implement the hysteresis width as a reliable parameter to control and calibrate the concentration of biomolecules in solution These observations partially resemble the appearance of a voltage hysteresis in output curves when sweeping source-to-drain voltage VSD upon functionalization with antibodies in silicon nanowire devices that were modelled by a memristor equation, and related to the capacitive effects [39,40]. The design the microfluidic assembly enables it to perform all the functionalization steps and

Materials andof

3.3.Results

Measurements Concept

Conclusions