Label-Free C-Reactive Protein Si Nanowire FET Sensor Arrays With Super-Nernstian Back-Gate Operation

Abstract

We present a CMOS-compatible double gate and label-free C-reactive protein (CRP) sensor, based on silicon on insulator (SOI) silicon nanowires arrays. We exploit a reference subtracted detection method and a super-Nernstian internal amplification given by the double gate structure. We overcome the Debye screening of charged CRP proteins in solutions using antibodies fragments as capturing probes, reducing the overall thickness of the capture layer. We demonstrate the internal amplification through the pH response of the sensor, in static and realtime working modes. While operated in back-gate configuration, the sensor shows excellent stability (<20 pA/min in the worst case), low hysteresis (<300 mV), and a great sensitivity up to 1.2 nA/dec toward CRP proteins in the linear response range. The reported system is an excellent candidate for the continuous monitoring of inflammation biomarkers in serum or interstitial fluid.

pH Quantification in Human Dermal Interstitial Fluid Using Ultra-Thin SOI Silicon Nanowire ISFETs and a High-Sensitivity Constant-Current Approach

“…The fabrication of silicon nanowire arrays on Silicon-On-Insulator (SOI) substrates have been performed at CEA LETI [12]. In our previous paper [13], we presented the main steps of the fabrication process resulting in arrays of nanowires with a thickness of 30 nm, width of 150 nm and length of 1 µm, connected in parallel. The gate stack is formed of a thin silicon dioxide interface layer, followed by a deposition of 2 nm of high-k dielectric (HfO 2 ).…”

Field effect transistor based wearable biosensors for healthcare monitoring

“…4 e. This configuration increases the sensor’s response, improves signal-to-noise ratio, and reduces signal drift and hysteresis [ 34 ]. Capua et al [ 35 ] developed a SiNW FET using this configuration to detect C-reactive protein. The sensor has excellent stability, low hysteresis, great sensitivity, and a negligible shift over time.…”

“…Various semiconductor materials have been used to fabricate FET, including silicon [ 35 ], metal oxides [ 18 ], III-V materials [ 39 ], transition metal dichalcogenides [ 39 ], organic semiconductors [ 40 ], graphene [ 2 ], carbon nanotubes [ 41 ], and black phosphorous [ 42 ]. Several criteria need to be considered for selecting the semiconductor for a bioFET sensor.…”

“…The reported device exhibited high sensitivity, real-time monitoring, excellent biocompatibility, low detection limits, and mechanical stability on the body. Recently, Capua et al [ 35 ] developed an FET biosensor using silicon nanowire arrays to detect C-reactive protein in ISF. The authors used SiNW arrays immobilized with antibody fragments to overcome Debye screening and enabled label-free detection.…”