3 research outputs found
Two Distinctly Separated Emission Colorimetric NIR Fluorescent Probe for Fast Hydrazine Detection in Living Cells and Mice upon Independent Excitations
Hydrazine
is carcinogenic and highly toxic so that it can lead
to serious environmental contamination and serious health risks although
it has been extensively used as an effective propellant and an important
reactive base in industry. Thus, the development of two-emission NIR
fluorescent probes for rapid detection of hydrazine with high selectivity
and sensitivity is of significance and of great challenge in both
biological and environmental sciences. Here, we report a two-emission
colorimetric fluorescent probe for the specific detection of hydrazine
based on hydrazinolysis reaction under physiological conditions. In
the presence of hydrazine, the probe showed an extremely remarkable
fluorescence enhancement at 627 nm compared to the decrease at 814
nm excited at different wavelength in aqueous solution. This distinct
difference of two emission intensities is suitable for detection of
low concentration hydrazine with a detection limit of 0.38 ppb. Addition
of hydrazine resulted in a remarkable color change from blue-green
to red observed by the naked eye. Kinetic study indicated a fast response
of the probe toward hydrazine in minutes. Furthermore, the probe can
bioimage hydrazine in living HeLa cells and mice with low cytotoxicity
and excellent biocompatibility
Presentation1.pdf
<p>With a layered structure, layered double hydroxide (LDH) has potential applications in remediation of anionic contaminants, which has been a hot topic for recent years. In this study, a Cl type Mg-Al hydrotalcite (Cl-LDH) was prepared by a co-precipitation method. The adsorption process of three pharmaceuticals and personal care products (PPCPs) [tetracycline (TC), diclofenac sodium (DF), chloramphenicol (CAP)] by Cl-LDH was investigated by X-ray diffraction (XRD), Zeta potential, dynamic light scattering (DLS), BET, Fourier transform infrared (FTIR) spectroscopy, and molecular dynamics simulation. The results showed that the adsorption equilibrium of TC and DF could be reached in 120 min, and the maximum adsorption capacity of the TC and DF were 1.85 and 0.95 mmol/g, respectively. The isothermal adsorption model of TC was fitted with the Freundlich adsorption model, and the isothermal adsorption model of DF was fitted with the Langmuir adsorption model. The adsorption dynamics of TC and DF followed the pseudo-second-order model. The adsorption mechanisms of the three PPCPs into Cl-LDH were different based on the experimental results and molecular dynamics simulation. The TC adsorption on Cl-LDH was accompanied by the electrostatic interactions between the negative charge of TC and the positive charge of Cl-LDH. The uptake of DF was attributed to anion exchange and electrostatic interaction. Cl-LDH does not adsorb CAP due to no electrostatic interaction. The molecular dynamic simulation further confirmed different configurations of three selected PPCPs, which were ultimately responsible for the uptake of PPCPs on Cl-LDH.</p
Well-Coupled Nanohybrids Obtained by Component-Controlled Synthesis and in Situ Integration of Mn<sub><i>x</i></sub>Pd<sub><i>y</i></sub> Nanocrystals on Vulcan Carbon for Electrocatalytic Oxygen Reduction
Development
of cheap, highly active, and robust bimetallic nanocrystal
(NC)-based nanohybrid (NH) electrocatalysts for oxygen reduction reaction
(ORR) is helpful for advancing fuel cells or other renewable energy
technologies. Here, four kinds of well-coupled Mn<sub><i>x</i></sub>Pd<sub><i>y</i></sub>(MnPd<sub>3</sub>, MnPd–Pd,
Mn<sub>2</sub>Pd<sub>3</sub>, Mn<sub>2</sub>Pd<sub>3</sub>–Mn<sub>11</sub>Pd<sub>21</sub>)/C NHs have been synthesized by in situ integration
of Mn<sub><i>x</i></sub>Pd<sub><i>y</i></sub> NCs
with variable component ratios on pretreated Vulcan XC-72 C using
the solvothermal method accompanied with annealing under Ar/H<sub>2</sub> atmosphere and used as electrocatalysts for ORR. Among them,
the MnPd<sub>3</sub>/C NHs possess the unique “half-embedded
and half-encapsulated” interfaces and exhibit the highest catalytic
activity, which can compete with some currently reported non-Pt catalysts
(e.g., Ag–Co nanoalloys, Pd<sub>2</sub>NiAg NCs, PdCo/N-doped
porous C, G-Cu<sub>3</sub>Pd nanocomposites, etc.), and close to commercial
Pt/C. Electrocatalytic dynamic measurements disclose that their ORR
mechanism abides by the direct 4e<sup>–</sup> pathway. Moreover,
their durability and methanol-tolerant capability are much higher
than that of Pt/C. As revealed by spectroscopic and electrochemical
analyses, the excellent catalytic performance of MnPd<sub>3</sub>/C
NHs results from the proper component ratio of Mn and Pd and the strong
interplay of their constituents, which not only facilitate to optimize
the d-band center or the electronic structure of Pd but also induce
the phase transformation of MnPd<sub>3</sub> active components and
enhance their conductivity or interfacial electron transfer dynamics.
This work demonstrates that MnPd<sub>3</sub>/C NHs are promising methanol-tolerant
cathode electrocatalysts that may be employed in fuel cells or other
renewable energy option