his study presents a method of simultaneous reduction and surface funcionalization of graphene oxide by a one-step poly(norepinephrine) funcionalization. The pH-induced aqueous functionalization of graphene oxide y poly(norepinephrine), a catecholamine polymer inspired by the robust dhesion of marine mussels, chemically reduced and functionalized graphene xide. Moreover, the polymerized norepinephrine (pNor) layer provided mulifunctionality on the reduced graphene oxide that includes surface-initiated olymerization and spontaneous metallic nanoparticle formation. This facile urface modifi cation strategy can be a useful platform for graphene-based ano-composites.

Simultaneous Reduction and Surface Functionalization of Graphene Oxide by MusselInspired Chemistry

National Institutes of Health (U.S.). Centers of Cancer and Nanotechnology Excellence (1U54CA151884-01)

In Vivo Compatibility of Graphene Oxide with Differing Oxidation States

Recent advances of supercapacitors based on two-dimensional materials

State of the art and recent advances in the ultrasound-assisted synthesis, exfoliation and functionalization of graphene derivatives.

Ultrasound‐assisted synthesis of FeTiO3/GO nanocomposite for photocatalytic degradation of phenol under visible light irradiation

In situ sonochemical reduction and direct functionalization of graphene oxide: A robust approach with thermal and biomedical applications.

Ultrasound assisted simultaneous reduction and direct functionalization of graphene oxide with thermal and cytotoxicity profile.

The inherent stability and solvent processability restrict the functional expression of graphene for biomedical applications. To resolve this problem graphene oxide (GrO) has emerged as a biomaterial for biomedical applications of graphene. The participation of O_K edges has been confirmed with synchrotron radiation near edge X-ray absorption fine structure (SR-NEXAFS). The as-prepared graphene oxide has been confirmed with 13C cross polymerization magic angle spinning (CP-MAS) solid state NMR, HRXPS, HRTEM, SAED, SEM, AFM, Raman, XRD, FTIR, UV, TGA, DTA, BET and Porosimeter, etc. The biomedical significance of graphene oxide has been supported by an extensive structural investigation. The underlying mechanism of biological activity of graphene oxide has been inferred through the synergistic impact of contributory factors (SICF). The cytotoxicity of graphene oxide has been evaluated with an SRB assay with living mammalian cell lines, human breast cancer cell line MCF-7 and monkey normal kidney cell line Vero. The estimated cell viabilities are greater than 80% over a 10–80 μg mL−1 concentration. The high cytocompatibility of graphene oxide has confirmed its low toxicity and hence its excellent biocompatibility. Moreover, the morphological effect on the Vero cell line has been endorsed by in vitro behaviour. The sensitivity of graphene oxide has been evaluated with minimum inhibitory concentration (MIC) against antifungal strain C. albicans (ATCC 10231) at 128 μg mL−1. However, for antibacterial strains S. aureus (ATCC 25923) and E. coli (ATCC 25922) the MIC of graphene oxide is 256 μg mL−1. The genetic variability greatly increases during the sub-culturing of strains; therefore the resistant behaviour of graphene oxide has been observed against NCIM strains. Additionally, the antioxidant activity of graphene oxide is 50.57–45.89%, at over 40–100 μg mL−1 concentration. Hence, the structural investigations of graphene oxide have complemented the findings for biological activity and emerged as an advanced functional biomaterial for biomedical applications of graphene.

Understanding the significance of O-doped graphene towards biomedical applications

Dispersion enhancing effect of sonochemically functionalized graphene oxide for catalysing antioxidant efficacy of curcumin

Ultrasonochemically driven graphene oxide (GrO) functionalization (f) with sulfanilamide (SA) near-edge catalyzed heterogeneous graphene oxide (h-GrO) as economic scalable f-(SA)GrO is reported. The novel in situ H2O association was subsequently aligned towards C–O–C active sites of GrO and f-(SA)GrO surfaces on a mechanistic HO˙ release with efficient sonothermocatalysis. Compared to GrO, the electronic bandwidth of heterogeneous f-(SA)GrO structure is reduced from 4.00 to 3.67 eV at 280 nm excitation. The contribution of heteroatoms (-N) of f-(SA)GrO at near-edges could have a greater bandwidth efficacy due to synergistic effect. The composition-driven structural alignments with near-edges have been investigated with synchrotron radiation soft X-ray absorption spectroscopy and high-resolution X-ray photoelectron spectroscopy. Efficient photoluminescent bandwidth structures at 3.67 and 1.87 eV for f-(SA)GrO and 4.00, 2.04 and 1.46 eV for GrO with their corresponding surface quantized electronic density contour images, photon flux, and power density were investigated. Sonothermocatalysis efficiencies for methylene blue (MB) by GrO and f-(SA)GrO sonocatalysts at regular time intervals up to 60 min are 68.68 to 83.05% and 81.44 to 87.31% respectively. Distorted sonothermocatalysis efficiencies for rhodamine B (RhB) are 43.71 to 61.38% and 47.7 to 53.39% respectively. The sonocatalyst f-(SA)GrO is thermodynamically more efficient (>85%) in MB sonothermocatalysis than GrO. Ultrasound time driven temperatures exhibited a thermal progression of sonothermocatalysis for MB and RhB degradation. It generated activation energy (Ea), frequency factor (A), enthalpy (ΔH), entropy (ΔS), and Gibbs energy (ΔG), which depict an oxidative radical degradation. Interdependence of ΔH, ΔS, and ΔG implies a contribution of SA vis-a-vis activation energy (0.489 and 0.342 J mol−1 for MB and 0.234 and 0.075 J mol−1 for RhB degradation) on an Arrhenius scale. The functional groups of sonocatalysts were restored after sonothermocatalysis of MB, detected from Fourier-transform infrared spectra and diffraction patterns, confirming their reusability.

Ultrasound accelerated near-edge functionalized heterogeneous graphene oxide sonocatalyst for surface optical bandwidth efficacy and in situ sonothermocatalysis

Gopal Avashthi

Papers

In situ sonochemical reduction and direct functionalization of graphene oxide: A robust approach with thermal and biomedical applications.

Ultrasound assisted simultaneous reduction and direct functionalization of graphene oxide with thermal and cytotoxicity profile.

Understanding the significance of O-doped graphene towards biomedical applications

Dispersion enhancing effect of sonochemically functionalized graphene oxide for catalysing antioxidant efficacy of curcumin

Ultrasound accelerated near-edge functionalized heterogeneous graphene oxide sonocatalyst for surface optical bandwidth efficacy and in situ sonothermocatalysis