Graphene Quantum Dots Electrochemistry and Development of Ultrasensitive Enzymatic Glucose Sensor
- PDF / 2,670,356 Bytes
- 17 Pages / 432 x 648 pts Page_size
- 66 Downloads / 169 Views
MRS Advances © 2018 Materials Research Society DOI: 10.1557/adv.2018.324
Graphene Quantum Dots Electrochemistry and Development of Ultrasensitive Enzymatic Glucose Sensor Sanju Gupta1,Tyler Smith 2, Alexander Banaszak 3, J ohn Boeckl 4 Department of Physics and Astronomy and Advanced Materials Institute, Western Kentucky University, Bowling Green, KY 42101, USA 1
The Gatton Academy of Mathematics and Science, 1906 College Heights Blvd, Bowling Green, KY 42101, USA 2
Department of Physics and Astronomy and The Gatton Academy of Mathematics and Science, 1906 College Heights Blvd, Bowling Green, KY 42101, USA 3
Air Force Research Laboratory, Wright-Patterson Air Force Base, Wright- PATT, OH 45433, USA 4
Address all correspondence to Sanju Gupta at [email protected]
Abstract
Graphene quantum dots (GQDs) - zero-dimensional materials - are sheets of a few nanometers in lateral dimension and exhibit quantum confinement and edge site effects where sp2-bonded carbon nanocore surrounded with edged plane functional moieties is promising as advanced electroactive sensing platforms. In this work, GQDs are synthesized by solvothermal and hydrothermal techniques, with optimal size of 5 nm. Their potential in fundamental (direct electron transfer) and applied (enzymatic glucose biosensor) electrochemistry are demonstrated. Glucose oxidase (GOx) immobilized on glassy carbon (GC) electrodes modified with GQDs are investigated by means of cyclic voltammetry, differential pulse voltammetry, and amperometry. Well-defined quasi-reversible redox peaks observed under various electrochemical parameters helped to determine diffusion coefficient (D) and first-order electron transfer rate (kET). The cyclic voltammetry curves showed homogeneous ion transport for GQD with D ranging between 8.45 × 10 −9 m2 s−1 and 3 × 10−8 m2 s−1 following GO < rGO < GQD < GQD (with FcMeOH as redox probe) < GOx/rGO < GOx/GO < HRP/GQDs < GOx/GQDs. The developed GOx-GQDs biosensor responds efficiently and linearly to the presence of glucose over concentrations ranging 10 μM and 3 mM with limit of detection 1.35 μM and sensitivity 0.00769 μA μM−1·cm−2 as compared with rGO (0.025 μA μM−1 cm−2, 4.16 μM) and GO (0.064 μA μM−1 cm−2, 4.82 μM) nanosheets. The high performance and stability of GQDs is attributed to sufficiently large surface-to-volume ratio, excellent biocompatibility, abundant hydrophilic edge site density, and partially
Downloaded from https://www.cambridge.org/core. University of Warwick, on 08 Apr 2018 at 02:19:30, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2018.324
hydrophobic planar sites that favors GOx adsorption on the electrode surface and versatile architectures to ensure rapid charge transfer and electron/ion conduction ( iT,∞, i cond ( L) iT [k k / L k exp( k / L)] and t 1 2 3 4 iT , creates a regenerative “positive” feedback loop. The opposite effect is observed when scanning an insulating or semiconducting region and diffusion to the electro
Data Loading...
