Complementary Metal–Oxide–Semiconductor Potentiometric Field-Effect Transistor Array Platform Using Sensor Learning for Multi-ion Imaging

Abstract

This work describes an array of 1024 ion-sensitive field-effect transistors (ISFETs) using sensor-learning techniques to perform multi-ion imaging for concurrent detection of potassium, sodium, calcium, and hydrogen. Analytespecific ionophore membranes are deposited on the surface of the ISFET array chip, yielding pixels with quasi-Nernstian sensitivity to K + , Na + , or Ca 2+ . Uncoated pixels display pH sensitivity from the standard Si 3 N 4 passivation layer. The platform is then trained by inducing a change in single-ion concentration and measuring the responses of all pixels. Sensor learning relies on offline training algorithms including k-means clustering and density-based spatial clustering of applications with noise to yield membrane mapping and sensitivity of each pixel to target electrolytes. We demonstrate multi-ion imaging with an average error of 3.7% (K + ), 4.6% (Na + ), and 1.8% (pH) for each ion, respectively, while Ca 2+ incurs a larger error of 24.2% and hence is included to demonstrate versatility. We validate the platform with a brain dialysate fluid sample and demonstrate reading by comparing with a gold-standard spectrometry technique.

Tissue Regeneration through Cyber‐Physical Systems and Microbots

“…[ 68 ] Small sensor size is also crucial in providing an opportunity to map analyte concentrations within the construct and provide higher spatial resolution. [ 58,60 ] Accordingly, actuating microbot can be used to focus on the specific area.…”

Concurrent Potentiometric and Amperometric Sensing With Shared Reference Electrodes

“…The emergence of ion-sensitive electrodes with low detection limits up to ultra trace levels have given rise to the importance of potentiometric sensing [4]. With ongoing research on miniaturising these electrodes further, potentiometry allows for the possibility of low ion measurement values in tiny sample sizes for ions such as potassium, sodium, pH values and even bacteria or toxicities [5] [6].…”

An Array of On-Chip Integrated, Individually Addressable Capacitive Field-Effect Sensors with Control Gate: Design and Modelling

“…Electrolyte-gated field-effect devices (EG-FED) have been recognized as a promising transducer in designing chemical and biological sensors because of their small size and weight, fast response time, real-time monitoring, label-free and multiplexed biomolecular detection, possibility of on-chip integration of EG-FEDs and signal-processing circuit and compatibility to micro-and nanofabrication technologies with the future prospect of large-scale production at relatively low costs [1][2][3][4][5][6][7][8]. In addition, miniaturized analysis systems (e.g., lab-on-a-chip devices or electronic tongues) based on on-chip integrated EG-FEDs in an array format have received tremendous attention due to their ability for multiplexed and (quasi)simultaneous assaying of multiple chemical or biological species [9][10][11][12][13][14]. Such multiplexed biochemical sensing systems may offer several advantages over devices for single-analyte detection, such as reduced assay time and sample volume, reduced costs and high throughput.…”