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A therapeutic reduced graphene oxide (RGO) is synthesized by using fucoidan (Fu) as the reducing and surface functionalizing agent. The synthesized Fu-RGO exhibits promising characteristics for therapeutic applications such as high dispersity in aqueous media, biocompatibility, selective cytotoxicity to cancer cells, high loading capacity of the anticancer drug, and photothermal conversion effect. Therefore, Fu-GO is successfully harnessed as a combinatorial cancer treatment platform through bio-functional (Fu), chemo (doxorubicin (Dox)) and photothermal (RGO with near-infrared irradiation) modalities.

New halogen/nitrogen dual-doped graphenes (X/N-G) with thermally tunable doping levels are synthesized via the thermal reduction of graphite oxide (GO) with stepwise-pyrolyzed ionic liquids. The doping process of halogen and nitrogen into the graphene lattice proceeds via substitutional or covalent bonding through the physisorption or chemisorption of in situ pyrolyzed dopant precursors. The doping process is performed by heating to 300-400 °C of ionic liquid, and the chemically assisted reduction of GO is facilitated by ionic iodine, resulting in I/N-G materials possessing about three and two orders of magnitude higher conductivity (∼22,200 S m(-1)) and charge carrier density (∼10(21) cm(-3)), compared to those of thermally reduced GO. The thermally tunable doping levels of halogen in X/N-G significantly increase the conductivity of doped graphene to ∼27,800 S m(-1).

Nitrogen doping in carbon nanotube (CNT) fibers using pyrolyzed ionic liquid induced interfacial hydrogen bonding between individual CNTs, enhancing mechanical properties and electrical conductivity simultaneously. In particular, the nitrogen doped CNT fiber using the ionic liquid BMI-I exhibited about 104%, 714%, and 38% increased tensile strength (0.65 N/tex), elastic modulus (83 N/tex), and electrical conductivity (1350 S cm(-1)), respectively, compared to pristine CNT fiber.

A chemical defect healing of reduced graphene oxide (RGO) was carried out via intramolecular cross-dehydrogenative coupling (ICDC) with FeCl3 at room temperature. The Raman intensity ratio of the G-band to the D-band, the IG/ID ratio, of the RGO was increased from 0.77 to 1.64 after the ICDC reaction. From XPS measurements, the AC=C/AC-C ratio, where the peak intensities from the C=C and C-C bonds are abbreviated as AC=C and AC-C, of the RGO was increased from 2.88 to 3.79. These results demonstrate that the relative amount of sp(2)-hybridized carbon atoms is increased by the ICDC reaction. It is of great interest that after the ICDC reaction the electrical conductivity of the RGO was improved to 71 S cm(-1), which is 14 times higher than that of as-prepared RGO (5 S cm(-1)).

Water-dispersible graphene was prepared by reacting graphite oxide and 6-amino-4-hydroxy-2-naphthalenesulfonic acid (ANS). X-ray diffraction study showed that the basal reflection (002) peak of graphite oxide was absent in the ANS-functionalized graphene (ANS-G), indicating crystal layer delamination. Ultraviolet-visible spectral data were recorded to assess the solubility of the ANS-G in water. Fourier transform infrared spectral analysis suggested the attachment of ANS molecules to the surface of graphene. Raman and x-ray photoelectron spectroscopy revealed that oxygen functionality in the graphite oxide had been removed during reduction. Atomic force microscopy found that the thickness of ANS-G in water was about 1.8 nm, much higher than that of single layer graphene. Thermal stability measurements also indicated successful removal of oxygen functionality from the graphite oxide and the attachment of thermally unstable ANS to the graphene surfaces. The electrical conductivity of ANS-G, determined by a four-point probe, was 145 S m(-1) at room temperature.