An Arrayed Micro‐glutamate Sensor Probe Integrated with On‐probe Ag/AgCl Reference and Counter Electrodes

Abstract

Complete all‐in‐one multi‐arrayed glutamate (Glut) sensors have been constructed on a silicon‐based micromachined probe composed of micro‐platinum (Pt) working electrodes, a micro‐silver/silver chloride (Ag/AgCl) reference electrode (RE), and a micro‐Pt counter electrode (CE). The OCP shift of the electrodeposited Ag/AgCl on‐probe micro‐reference electrode compared with a Ag/AgCl wire is <0.1 mV/h. The composition ratio of Ag, Cl, and Pt on the electrodeposited on‐probe micro‐reference electrode is observed to be 1.00 : 0.48 : 0.02 analyzed by EDS. The miniaturized amperometric Glut biosensors were constructed on working electrode sites (electrode area: ∼8.5×10−5 cm2) of the microprobe modified with glutamate oxidase (GlutOx) enzyme layers for the selective, fast, and continuous detection of L‐glutamate. The sensor selectivity towards common electroactive interferents has been improved significantly by coating the electrode surface with perm‐selective polymer layers, overoxidized polypyrrole (PPY) and Nafion®. The sensitivity, detection range, and response time of the proposed all‐in‐one Glut biosensors are 204.7±5.8 nA μM−1 cm−2 (N=5), 4.99–109 μM, and 2.7±0.3 sec, respectively and no interferent signals of AA and DA were observed. The sensor can be reused over 19 times of continuous repetitive operation (total measurement time: ∼4 hours) and the sensor sensitivity can retain up to four weeks of storage.

Micro- and nano-devices for electrochemical sensing

“…Moreover, a highly integrated Au MEA biosensing platform was realized for the detection of glucose, lactose, phenolic compounds, and herbicides for agrifood screening [ 59 ]. Another relevant example of an integrated biosensing platform was given by Hoa et al, with the design of a micromachined probe composed of a micro-Pt working electrode, a micro-Ag/AgCl reference electrode (RE), and a micro-Pt counter electrode (CE) [ 60 ]. In this case, glutamate detection was carried out in human serum upon functionalization of the sensing area with GluOx and an over-oxidized PPy/Nafion permselective membrane.…”

Development of medical imaging sensors

“…It has been found through experiments that the sensor can be used continuously for about 4 h, and the sensor sensitivity can retain up to 4 weeks of storage. 14 The mechanism of forming an AgCl layer on an Ag substrate by cyclic voltammetry was evaluated. Through the related experiments and analysis, the related mechanisms of surface morphology and surface chemistry were discussed.…”

An investigation of the Vickers hardness of polishing pads using simulations based on microtomography model

“…Within the intricate IC fabrication process, chemical mechanical polishing (CMP) constitutes a critical step. This technique involves the use of a porous pad and a tailored slurry to effectively remove nanoscale film materials, thereby enabling the planarization of surfaces in microscale devices such as microcontrollers, integrated chips, and solid-state devices [1][2][3][4][5][6][7] Within the scope of CMP, the rate at which material is removed from the wafer is significantly impacted by the hardness and microstructure of the polishing pad. This is a result of the complex interaction between the applied polishing pressure and the rotational velocity of platen during the CMP process, which is heavily influenced by the pad's physical properties and its microscale architecture.…”