Gold nanoparticle decorated graphene sheet-polypyrrole based nanocomposite: its synthesis, characterization and genosensing application

Abstract

We report herein the synthesis of gold nanoparticle (GNP) decorated-graphene sheets (GO-GNPs) using the template of graphene oxide (GO) by a one-pot solution-based method. A polypyrrole-GO decorated GNP nanocomposite (GO-GNP/PPY) has been electropolymerized using a potentiodynamic method on an indium tin oxide (ITO) coated glass substrate. The as-synthesized nanocomposites are characterized by transmission electron microscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared and Raman spectroscopy. It has been found that GNPs of ca. 13 nm are uniformly dispersed on the surface of GO, and have a high electrochemically active surface area. The surface morphology studies show that PPY structure changes from nanoflowers to nanostars and then to nanosheets with an increase in the scan rate (20-200 mV s(-1)). The prepared GO-GNP/PPY/ITO electrode was further used as a genosensor, where the electrochemical response was measured using methylene blue (MB) as a redox indicator. The genosensor shows a response time of 60 s with high sensitivity (1 × 10(-15) M) and linearity (1 × 10(-15)-1 × 10(-6) M) with the correlation coefficient of 0.9975.

Tuning the Multifunctional Surface Chemistry of Reduced Graphene Oxide via Combined Elemental Doping and Chemical Modifications

“…Furthermore for all of the cys-N-rGOs studied, the appearance of a new peak near 1435 cm –1 (enlarged Figure A), which can be attributed to C–S vibrations, was also detected . A detailed inspection of the two peaks positioned at 1384 and 1548 cm –1 (enlarged Figure A), which can be attributed to the stretching vibrations of C–N and N–H, respectively, was also identified. − It is essential to note that all the peaks corresponding to N–H, C–N, and S–H vibrations were not detected in the FTIR spectra of their respective N-rGO precursors. Moreover, no absorption associated with the stretching vibration of the S–H group, commonly recorded between 2500 and 2600 cm –1 was observed, signifying the breaking of the S–H bond in cysteamine to covalently attach on the reduced graphene sheets via thiol-ene click functionalization. , Coupled with the strong evidence from these observations, we can infer the successful grafting of the cysteamine functional groups onto the graphene framework via the thermal thiol-ene click reaction, which converted the N-GO and N-rGO precursors to cys-N-GO and cys-N-rGOs, respectively.…”

“…55 A detailed inspection of the two peaks positioned at 1384 and 1548 cm –1 (enlarged Figure 7A), which can be attributed to the stretching vibrations of C–N and N–H, respectively, was also identified. 56−58 It is essential to note that all the peaks corresponding to N–H, C–N, and S–H vibrations were not detected in the FTIR spectra of their respective N-rGO precursors. Moreover, no absorption associated with the stretching vibration of the S–H group, commonly recorded between 2500 and 2600 cm –1 was observed, signifying the breaking of the S–H bond in cysteamine to covalently attach on the reduced graphene sheets via thiol-ene click functionalization.…”

Electrochemical Synthesis of Polypyrrole, Reduced Graphene Oxide, and Gold Nanoparticles Composite and Its Application to Hydrogen Peroxide Biosensor

“…Lam et al reported a dopamine electrochemical biosensor based on the electrodeposition of PPy and nanoAu on chemical etching-graphene modified electrode [13]. More recently, Tiwari et al reported a chemical-electrochemical route for the synthesis of a PPy, graphene oxide, and nanoAu nanocomposite [14]. First, a nanoAu–graphene sheet was fabricated using a chemical method, with two reduction agents sodium citrate dehydrate and sodium borohydrate at 100 °C.…”

Electroconductive multi-functional polypyrrole composites for biomedical applications

“…The final product was fabricated via the attachment of a DNA probe on the surface of the nanocomposite electrode. The incorporation of polypyrrole into this genosensor improved the conductivity of the electrode and enhanced the immobilization of the DNA probe onto the electrode surface [232] .…”