Graphite oxide multilayers for device fabrication: Enzyme‐based electrical sensing of glucose

Abstract

In this paper, the use of graphite oxide multilayers as a transducer material for the fabrication of electronic devices is outlined. Graphite oxide flakes were produced in a solution‐based exfoliation method optimized for large area thin layers with narrow size distribution. A dielectrophoretic technique was used for scalable trapping of the graphite oxide onto the microelectrode pairs patterned over glass chips. The graphite oxide trapped in between microelectrode gaps was subjected to a very rapid thermal annealing step in ambient in order to make good electrical contacts with source and drain electrodes. After this, the graphite oxide devices were characterized for their electrical transport using impedance spectroscopy and field‐effect measurements in an electrochemical gate configuration. The conductivities of the graphite oxide devices were tested against the thermal treatment in air in order to determine a nominal burn‐out as well as the optimal parameters for device characteristics. The devices were surface modified with glucose oxidase and deployed for sensor operation. This work suggests for the use of graphite oxide thin‐layers as an easy and suitable alternative for the fabrication of electronic sensor platforms circumventing the dependence over tedious chemical and physical graphene oxide reduction methods. Schematic illustration of the graphite oxide (GrO) multilayer‐based electronic chips fabricated over glass substrates. The chips were deployed as sensors for the electronic detection of glucose. Schematics not fit to scale.

Wafer-scale fabrication of microelectrode arrays on optically transparent polymer foils for the integration of flexible nanoscale devices

“…The devices were thermally annealed to obtain Ohmic contacts. The impedance behavior of a typical rGrO device after annealing is shown in figure 4(b) (with a Nyquist plot in the inset) representative of typical resistor-like behavior similar to our previous reports for rGrO devices on glass substrates [54]. A 50 mV sine stimulation signal was applied between drain and source contacts with a frequency span from 1 Hz to 100 kHz.…”

“…After the resist development, cleaning and drying, the foils were placed in the evaporation chamber for metal deposition via the PVD process. A standard protocol for deposition of 30 nm Ti and 120 nm Au was carried out, as reported for the fabrication of sensor chips on glass wafers in our previous works [53,54]. After the metal deposition, the foils were subjected to a lift-off process.…”

Universal protocol for the wafer-scale manufacturing of 2D carbon-based transducer layers for versatile biosensor applications

“…Our scientific work presents all production steps to illustrate that the cost-effective manufacture of such a sensor concept is truly feasible with existing technologies. Therefore, we made it our task to give priority to pure sensor fabrication in this manuscript and presented a comprehensive fabrication protocol that mainly deals with the wafer-scale fabrication of (r)GO transducer [ 1 , 2 ] for biosensor applications exemplified in SPR [3] , impedance spectroscopy [ 4 , 5 ] and ion-sensitive field-effect transistors (ISFETs) [ 6 , 7 ] configurations. These established works serve as a comprehensive universal fabrication guideline for readers.…”

“…These successfully integrated rGO thin films are electrically contacted with Ti/Au electrodes. The conductor tracks are hermetically sealed with a highly stable borosilicate glass (BSK) passivation so that this production is perfect for sensor applications in high ionic-strength solutions in which electrical impedance spectroscopy [ 4 , 5 ] and ISFETs [ 6 , 7 ] can operate. Fig.…”

Graphene based Materials for Bioelectronics and Healthcare

“…In the successive plots, transition of very high resistivity of the GrO multilayers exhibiting a "capacitive" behavior to a typical resistive characteristics after the efficient reduction process and formation of rGrO devices can be seen. [91] Thermal annealing of GBMs in specialized gaseous environments has also been used for doping. [105] Other than this, annealing methods can also be used to tune the work function of rGO thin-films.…”