Vertically Oriented Zinc Oxide Nanorod-Based Electrolyte-Gated Field-Effect Transistor for High-Performance Glucose Sensing

Abstract

Nanomaterial-based biosensors are a promising fit for portable and field-deployable diagnosis sensor devices due to their mass production, miniaturization, and integration capabilities. However, the fabrication of highly stable and reproducible biosensor devices is challenging. In this work, we grow a vertically oriented architecture of zinc oxide nanorods onto the active working area (i.e., the channel between the source and drain) of a field-effect transistor (FET) using a low-temperature hydrothermal method. The glucose oxidase enzyme was immobilized on the zinc oxide nanorod surface by a physical adsorption method to fabricate the electrolyte-gated FET-based glucose biosensor. The electrical properties of the electrolyte-gated FET biosensor were measured with different glucose concentrations. We found a linear increase in current up to 80 mM glucose concentration with high sensitivity (74.78 μA/mMcm2) and a low detection limit (∼0.05 mM). We illustrate a highly reproducible fabrication process of zinc oxide nanorod-based FETs, where vertically grown nanorods with a higher surface-to-volume ratio enhance the enzyme immobilization, provide a microenvironment for longer enzyme activity, and translate to better glucose sensing parameters. Additionally, our electrolyte-gated FET biosensor showed promising application in freshly drawn mouse blood samples. These findings suggest a great opportunity to translate into practical high-performance biosensors for a broad range of analytes.

Power and Sensitivity Management of Carbon Nanotube Transistor Glucose Biosensors

“…One hundred randomly selected FETs were tested in a liquid configuration with 1 × PBS as the electrolyte. An Ag/AgCl reference electrode was inserted into the solution as the LG electrode. , The stable reference electrode of Ag/AgCl can provide a control voltage over the channel by producing an EDL at the interface of Y 2 O 3 and the electrolyte. The Au NP layer is noncontinuous and separated from the channel by the Y 2 O 3 dielectric layer.…”

Electrochemical Sensing of Uric Acid with Zinc Oxide Nanorods Decorated with Copper Oxide Nanoseeds

“…Currently, there have been increasing reports of nanomaterial-based non-enzymatic sensors for detection of different analytes. − Different nanostructures of nanomaterials (i.e., CuO, cuprous oxide (Cu 2 O), ZnO, manganese dioxide (MnO 2 ), iron­(III) oxide (Fe 2 O 3 ), nickel oxide (NiO), cerium­(IV) oxide (CeO 2 ), tungsten disulfide (WS 2 ), cobalt oxide (Co 3 O 4 ), tin­(IV) oxide (SnO 2 ), molybdenum disulfide (MoS 2 ), MXene, carbon black, etc.) and their nanocomposites (i.e., ZnO-CuO, ZnO-Au, ZnO-Fe 2 O 3 , ZnO-polyaniline, ZnO-MWCNTs, etc.)…”

Extended-Gate FET Biosensor Based on GaN Micropillar Array and Polycrystalline Layer: Application to Hg2+ Detection in Human Urine

“…21,22 For EGFET biosensor, compared with the crawling nanowire, vertically grown nanowires (e.g., micropillar array, nanorod array) are independent of each other and can expose more side surfaces, making the nanowire array more sensitive to external charge. 24,25 Currently, GaN micropillar array (GMPA) are mainly applied as fluorescence/electrochemical biosensors, only two reports employed crawling GaN nanowires as extended-gate of EGFET biosensor. 6,16 But in fact, the detection sensitivity is poor even with high surface area, because the impedance of GaN nanowires grown by conventional processes is large.…”

“…For EGFET biosensor, extended-gate electrode materials with large surface area and low impedance are beneficial to improve the sensing performance, e.g., detection sensitivity and limit of detection (LOD). − , To our best knowledge, materials of Si, SnO 2 , ITO, ZnO, and Ga 2 O 3 with nanorod structure has been used as extended-gate to enhance the sensing performance. ,,,− However, these materials have poor electrical conductivity and require to combine with conductive materials (e.g., Al layer, FTO, Ag wire layer, or corresponding seed layer), this would complicate the preparation, reduce repeatability and lead to reduced practicality. ,,,− In contrast, GaN material can achieve not only high surface area by growing nanowire or nanowire array structures but also high electrical conductivity by using low temperature MOCVD growth. − Furthermore, GaN exhibits excellent chemical stability for biosensor application, and the maturity of GaN based electronic devices (e.g., transistor, LED, solar cell) ensure the integration of GaN-based biosensor with GaN electronic devices, which would bring out multifunctional chip. , For EGFET biosensor, compared with the crawling nanowire, vertically grown nanowires (e.g., micropillar array, nanorod array) are independent of each other and can expose more side surfaces, making the nanowire array more sensitive to external charge. , Currently, GaN micropillar array (GMPA) are mainly applied as fluorescence/electrochemical biosensors, only two reports employed crawling GaN nanowires as extended-gate of EGFET biosensor. , But in fact, the detection sensitivity is poor even with high surface area, because the impedance of GaN nanowires grown by conventional processes is large. Thus, preparing GMPA with high electrical conductivity can further improve the detection sensitivity and LOD, but this is still a challenge.…”