Glucose Sensing Using Functionalized Amorphous In–Ga–Zn–O Field-Effect Transistors

Abstract

Recent advances in glucose sensing have focused on the integration of sensors into contact lenses to allow noninvasive continuous glucose monitoring. Current technologies focus primarily on enzyme-based electrochemical sensing which requires multiple nontransparent electrodes to be integrated. Herein, we leverage amorphous indium gallium zinc oxide (IGZO) field-effect transistors (FETs), which have found use in a wide range of display applications and can be made fully transparent. Bottom-gated IGZO-FETs can have significant changes in electrical characteristics when the back-channel is exposed to different environments. We have functionalized the back-channel of IGZO-FETs with aminosilane groups that are cross-linked to glucose oxidase and have demonstrated that these devices have high sensitivity to changes in glucose concentrations. Glucose sensing occurs through the decrease in pH during glucose oxidation, which modulates the positive charge of the aminosilane groups attached to the IGZO surface. The change in charge affects the number of acceptor-like surface states which can deplete electron density in the n-type IGZO semiconductor. Increasing glucose concentrations leads to an increase in acceptor states and a decrease in drain-source conductance due to a positive shift in the turn-on voltage. The functionalized IGZO-FET devices are effective in minimizing detection of interfering compounds including acetaminophen and ascorbic acid. These studies suggest that IGZO FETs can be effective for monitoring glucose concentrations in a variety of environments, including those where fully transparent sensing elements may be of interest.

Quasi-Two-Dimensional Metal Oxide Semiconductors Based Ultrasensitive Potentiometric Biosensors

“…The detailed surface functionalization process is described in the Experimental and it was confirmed by XPS analysis (Figures S8 and S9). The functionalization process has been reported and characterized by other researchers, 76 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 12 4b shows that a device functionalized with boronic acid exhibited a significant decrease (18%) in sensing current upon the addition of a 3 pM glucose solution (in 0.1X PBS). This agrees with the effect of boronate anion-glucose electrostatic gating, which depletes electron carriers at the semiconductor/liquid interface in the n-type In 2 O 3 film.…”

Review of recent advances in flexible oxide semiconductor thin-film transistors

“…The biosensors on the flexible array are also important because they make real-time monitoring possible by adopting the human body. Various types of biosensor have been investigated [85], and the active-matrix-based sensor array is the key technology for transforming various types of signals into electrical signals, and for analyzing signals. For example, Figure 10 shows a glucosebiosensor embedded on IGZO TFTs, whose transfer characteristics were changed by changing concentration of glucose.…”

Recent advances in nanowires-based field-effect transistors for biological sensor applications

“…Recently, ZnO NWs-based FET biosensors for glucose detection were reported with enhanced sensing performances. For further advancement in glucose sensing, Du et al (2016) reported bottom-gated indium gallium ZnO (IGZO) FET for noninvasive continuous glucose monitoring and device integration into contact lenses. Yu et al (2013) demonstrated the fabrication of a self-powered, piezotronic effect enhanced glucose sensor based on metal-semiconductor-metal structured single ZnO NW device.…”