Fengping Hou

A facile chemical method to produce superparamagnetic graphene oxide-Fe3O4 hybrid composite and its application in the removal of dyes from aqueous solution

A superparamagnetic graphene oxide–Fe3O4 hybrid composite (GO–Fe3O4) was prepared via a simple and effective chemical method. Amino-functionalized Fe3O4 (NH2-Fe3O4) particles are firmly deposited on the graphene oxide sheets. The graphene oxide sheets could prevent NH2-Fe3O4 particles from agglomeration and enable a good dispersion of these oxide particles. The as-prepared GO–Fe3O4 hybrid composite had a much higher thermal stability than graphene oxide. The amount of NH2-Fe3O4 loaded on GO was estimated to be 23.6 wt% by atomic absorption spectrometry. The specific saturation magnetization (Ms) of the GO–Fe3O4 hybrid composite is 15 emu g−1. The magnetic GO–Fe3O4 composite has been employed as adsorbent for the magnetic separation of dye contaminants from water. The adsorption test of dyes (Methylene Blue (MB) and Neutral Red (NR)) demonstrates that it only takes 30 min for MB and 90 min for NR to attain equilibrium. The adsorption capacities for MB and NR in the concentration range studied are 167.2 and 171.3 mg g−1, respectively. The GO–Fe3O4 hybrid composite can be easily manipulated in magnetic field for desired separation, leading to the removal of dyes from polluted water. These GO–Fe3O4 hybrid composites have great potential applications in removing organic dyes from polluted water.

Biomimetic and Cell-Mediated Mineralization of Hydroxyapatite by Carrageenan Functionalized Graphene Oxide

In bone tissue engineering, it is imperative to design multifunctional biomaterials that can induce and assemble bonelike apatite that is close to natural bone. In this study, graphene oxide (GO) was functionalized by carrageenan. The resulting GO-carrageenan (GO-Car) composite was further used as a substrate for biomimetic and cell-mediated mineralization of hydroxyapatite (HA). It was confirmed that carrageenan on the GO surface facilitated the nucleation of HA. The observation of the effect of the GO-Car on the adhesion, morphology, and proliferation of MC3T3-E1 cells was investigated. In vitro studies clearly show the effectiveness of GO-Car in promoting HA mineralization and cell differentiation. The results of this study suggested that the GO-Car hybrid will be a promising material for bone regeneration and implantation.

Cu2+-selective fluorescent chemosensor based on coumarin and its application in bioimaging

A new fluorescent sensor L1 based on coumarin was synthesized. It shows high sensitivity and selectivity toward Cu(2+) in aqueous solution. The complexation mode and corresponding quenching mechanism were elucidated by ESI-MS and DFT calculations. In addition, biological imaging studies have demonstrated that L1 can detect Cu(2+) in living cells.

Fluorescent graphene oxide composites synthesis and its biocompatibility study

In this research, we developed a “clean” and “wet” route to produce sandwich-like fluorescent CdQ2/GO composites sheets starting from graphene oxide (GO) and Cd2+ in water/ethanol solution in one pot. The as-prepared CdQ2/GO composites sheets were fully characterized by IR, XRD, TEM and TGA analysis. The CdQ2/GO composites exhibited a strong fluorescence emission centered at 500 nm. Both the solid sample and the water dispersion could demonstrate strong green fluorescence. When incubated with Hep G2 cells at 37 °C, the CdQ2/GO composites were found to adhere to the surroundings of the cell membrane, resulting in strong green fluorescence observed by laser confocal fluorescence microscopy. MTT assay experiment results showed that this kind of composite material had low cytotoxicity at the concentration of 400 μg mL−1. We believe this method and composite materials will open up a brand new avenue for wider applications of graphene-based materials in the detection of other types of biomarkers, biomolecular interactions, and fluorescence imaging in vitro and in vivo.

A rhodamine-based “turn-on” fluorescent chemodosimeter for Cu2+ and its application in living cell imaging

A new fluorescent probe 1, N-(Rhodamine-6G)lactam-hydrazinecarbothioamide, was synthesized as a fluorescent and colorimetric chemodosimeter in aqueous solution for Cu(2+). Following Cu(2+)-promoted ring opening, redox and hydrolysis reactions, comparable amplifications of absorption and fluorescence signals were observed upon addition of Cu(2+); this suggests that chemodosimeter 1 effectively avoided the fluorescence quenching caused by the paramagnetic nature of Cu(2+). Importantly, 1 can selectively recognize Cu(2+) in aqueous media in the presence of other trace metal ions in organisms, abundant cellular cations and the prevalent toxic metal ions in the environment with high sensitivity (detection limit <3 ppb) and a rapid response time (<2 min). In addition, the biological imaging study has demonstrated that 1 can detect Cu(2+) in the living cells.