3 research outputs found
Hybrid Composite Ni(OH)<sub>2</sub>@NiCo<sub>2</sub>O<sub>4</sub> Grown on Carbon Fiber Paper for High-Performance Supercapacitors
We
have successfully fabricated and tested the electrochemical performance
of supercapacitor electrodes consisting of NiÂ(OH)<sub>2</sub> nanosheets
coated on NiCo<sub>2</sub>O<sub>4</sub> nanosheets grown on carbon
fiber paper (CFP) current collectors. When the NiCo<sub>2</sub>O<sub>4</sub> nanosheets are replaced by Co<sub>3</sub>O<sub>4</sub> nanosheets,
however, the energy and power density as well as the rate capability
of the electrodes are significantly reduced, most likely due to the
lower conductivity of Co<sub>3</sub>O<sub>4</sub> than that of NiCo<sub>2</sub>O<sub>4.</sub> The 3D hybrid composite NiÂ(OH)<sub>2</sub>/NiCo<sub>2</sub>O<sub>4</sub>/CFP electrodes demonstrate a high areal capacitance
of 5.2 F/cm<sup>2</sup> at a cycling current density of 2 mA/cm<sup>2</sup>, with a capacitance retention of 79% as the cycling current
density was increased from 2 to 50 mA/cm<sup>2</sup>. The remarkable
performance of these hybrid composite electrodes implies that supercapacitors
based on them have potential for many practical applications
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
A Retrievable and Highly Selective Fluorescent Probe for Monitoring Sulfide and Imaging in Living Cells
A novel selective fluorescent chemosensor based on an
8-hydroxyquinoline-appended
fluorescein derivative (<b>L1</b>) was synthesized and characterized.
Once combined with Cu<sup>2+</sup>, it displayed high specificity
for sulfide anion. Among the various anions, only sulfide anion induced
the revival of fluoresecence of <b>L1</b>, which was quenched
by Cu<sup>2+</sup>, resulting in “off–on”-type
sensing of sulfide anion. What’s more, the sensor was retrievable
to indicate sulfide anions with Cu<sup>2+</sup>, and S<sup>2–</sup>, in turn, increased. With the addition of Cu<sup>2+</sup>, compound <b>L1</b> could give rise to a visible pink-to-yellow color change
and green fluorescence quenching. The resulting yellow solution could
change to pink and regenerate to green fluorescence immediately upon
the addition of sulfide anion; however, no changes were observed in
the presence of other anions, including CN<sup>–</sup>, P<sub>2</sub>O<sub>7</sub><sup>4–</sup>, and other
forms of sulfate, making compound <b>L1</b> an extremely selective
and efficient sulfide chemosensor. The signal transduction occurs
via reversible formation–separation of complex <b>L1</b>Cu and CuS. What’s more, the biological imaging study has
demonstrated that the chemosensor can detect sulfur anions in biological
systems at a relatively low concentration