The Enhanced Electro-catalytic Performance of Au@Pd Nanoparticles Self-assembled on Fluorine-Modified Multi-walled Carbon Nanotubes for Methanol Oxidation

Bidirectional hybridized hairpin DNA fluorescent aptasensor based on Au-Pd NPs and CDs for ratiometric detection of AFB1

A novel and simple ratiometric fluorescent aptasensor was developed for the sensitive detection of aflatoxin B1 (AFB1). A hairpin DNA (h-DNA) was independently synthesized as the basic skeleton, and the bidirectional hybridization of h-DNA can increase the load of aptamer and signal probes, thereby realizing signal amplification. The high-efficiency fluorescence resonance energy transfer interaction between gold-palladium nanoparticles (Au-Pd NPs) and the self-synthesized fluorescent probe carbon dots (CDs) was utilized. Moreover, the label-free probe SYBR Green I (SG I) dye was introduced to form a double-signal probe with CDs, and a ratiometric sensor with FCDs/FSG I as a response signal was constructed. The ratio strategy can eliminate the fluctuation of external factors, thus improving the accuracy and reliability of the sensor. The quenching effect of Au-Pd NPs on CDs was 1.4 times that of AuNPs and 3.4 times that of Pd NPs, respectively. In the range 1-100 ng/mL, FCDs/FSG I showed a good linear relationship with the logarithm of the concentration of AFB1, and the limit of detection was as low as 0.07 ng/mL. The sensor was used to detect AFB1 in spiked peanuts and wine samples, and the recovery was between 91 and 115%, indicating that the sensor has high application potential in real sample analysis.

Elucidating Surface Plasmon Damping and Fano Resonance Induced by Epitaxial Growth of Palladium on Single Gold Nanorods

Plasmon damping and Fano resonance induced in the growth of palladium (Pd) on gold nanorods (AuNRs) have been poorly understood. Herein, we investigated the optical properties and morphologies of single AuNRs@Pd (core@shell) synthesized using epitaxial Pd growth at different Pd concentrations. The localized surface plasmon resonance (LSPR) spectra of single AuNRs@Pd showed characteristic subradiant and superradiant peaks as well as Fano resonance as a spectral dip, which was highly influenced by the Pd shell thickness. The occurrence of the Fano resonance during the Pd growth was further verified by in situ real-time observation experiments. We then elucidated time-dependent, real-time variations in LSPR peak wavelength, metal-induced surface damping, and Fano resonance mode of single AuNRs@Pd during Pd shell formation in three successive phases: Pd reduction, nucleation, and growth. Therefore, this study provides new insights into metal interface damping, the Fano resonance, and optical tunability by engineering the Fano resonance energy and Pd shell thickness.

Green magnetic nanomaterial as antibiotic release vehicle: The release of pefloxacin and ofloxacin

The increased efflux of fluoroquinolone antibiotics to the environment has become of worldwide concern due to their potential to disturb aquatic ecosystems. How to improve the antibiotic release is a challenge. In this work, magnetic Fe₃O₄ nanoparticles as a drug release vehicle were prepared using the green synthesis method. It is a simple and environmental friendly technique that employs the plant extract as a reducing and coating agent during the preparation process. Antibiotics ofloxacin and pefloxacin served as the drug model and the drug release behavior was tested at various pH levels. The release efficiency of ofloxacin from Fe₃O₄ reached 99.6% and for pefloxacin it was 57.0% at 310 K after 120 h (pH 10.5). The scanning electron microscope images show that Fe₃O₄ particles ranged in size from 10 to 40 nm and magnetism testing indicated that saturation magnetization was 58.7 emu/g. Furthermore, zeta potential, FTIR, UV-VIS, XRD and XPS were used to provide the evidence to support the release mechanism, where was based on the pH control. Our work clearly demonstrated that Fe₃O₄ nanoparticles were a potential as a targeted drug delivery system.

Novel electrocatalysts for borohydride fuel cells: enhanced power generation by optimizing anodic core–shell nanoparticles on reduced graphene oxide

C_Ni–S_Pd exhibits an excellent performance and rGO is a superior support compared with Vulcan and MWCNTs.