Flower-like porous BCN assembled by nanosheets for paclitaxel delivery.

Developing smart drug delivery systems has become a feasible solution to overcome the challenges in cancer chemotherapeutics. In this work, porous boron carbon nitride (ZBCN) nanomaterials with flower-like structures assembled with BCN nanosheets were synthesized by using ZIF-L as a template. The rich hydroxyl groups on the BCN surfaces make it highly dispersible and stable in aqueous solutions. Additionally, ZBCN exhibits stable photoluminescence properties that can be utilized for cellular uptake and tracking of drug delivery. Furthermore, the flower-like ZBCN structure contributes to a large specific surface area of up to 340 m2 g-1 and a pore volume of 1.03 cm3 g-1; and the presence of rich macropores results in a high drug loading capacity of 116 wt% for paclitaxel. In vitro and in vivo anticancer experiments demonstrated that ZBCN exhibits excellent performance in delivering anticancer drugs, with in vivo tumor inhibition of 58%. This study presents a novel template method for preparing porous BCN nanomaterials, offering a promising platform for high-performance anticancer drug delivery.

Effects of Alternating Magnetic Fields on the OER of Heterogeneous Core-Shell Structured NiFe2O4@(Ni, Fe)S/P.

Composition optimization, structural design, and introduction of external magnetic fields into the catalytic process can remarkably improve the oxygen evolution reaction (OER) performance of a catalyst. NiFe2O4@(Ni, Fe)S/P materials with a heterogeneous core-shell structure were prepared by the sulfide/phosphorus method based on spinel-structured NiFe2O4 nanomicrospheres. After the sulfide/phosphorus treatment, not only the intrinsic activity of the material and the active surface area were increased but also the charge transfer resistance was reduced due to the internal electric field. The overpotential of NiFe2O4@(Ni, Fe)P at 10 mA cm-2 (iR correction), Tafel slope, and charge transfer resistance were 261 mV, 42 mV dec-1, and 3.163 Ω, respectively. With an alternating magnetic field, the overpotential of NiFe2O4@(Ni, Fe)P at 10 mA cm-2 (without iR correction) declined by 45.5% from 323 mV (0 mT) to 176 mV (4.320 mT). Such enhancement of performance is primarily accounted for the enrichment of the reactive ion OH- on the electrode surface induced by the inductive electric potential derived from the Faraday induction effect of the AMF. This condition increased the electrode potential and thus the charge transfer rate on the one hand and weakened the diffusion of the active substance from the electrolyte to the electrode surface on the other hand. The OER process was dominantly controlled by the charge transfer process under low current conditions. A fast charge transfer rate boosted the OER performance of the catalyst. At high currents, diffusion exerted a significant effect on the OER process and low OH- diffusion rates would lead to a decrease in the OER performance of the catalyst.

Enhanced Alkaline Oxygen Evolution Using Spin Polarization and Magnetic Heating Effects under an AC Magnetic Field.

Renewable electricity from splitting water to produce hydrogen is a favorable technology to achieve carbon neutrality, but slow anodic oxygen evolution reaction (OER) kinetics limits its large-scale commercialization. Electron spin polarization and increasing the reaction temperature are considered as potential ways to promote alkaline OER. Here, it is reported that in the alkaline OER process under an AC magnetic field, a ferromagnetic ordered electrocatalyst can simultaneously act as a heater and a spin polarizer to achieve significant OER enhancement at a low current density. Moreover, its effect obviously precedes antiferromagnetic, ferrimagnetic, and diamagnetic electrocatalysts. In particular, the noncorrected overpotential of the ferromagnetic electrocatalyst Co at 10 mA cm-2 is reduced by a maximum of 36.6% to 243 mV at 4.320 mT. It is found that the magnetic heating effect is immediate, and more importantly, it is localized and hardly affects the temperature of the entire electrolytic cell. In addition, the spin pinning effect established on the ferromagnetic/paramagnetic interface generated during the reconstruction of the ferromagnetic electrocatalyst expands the ferromagnetic order of the paramagnetic layer. Also, the introduction of an external magnetic field further increases the orderly arrangement of spins, thereby promoting OER. This work provides a reference for the design of high-performance OER electrocatalysts under a magnetic field.

Rubidium Doping to Enhance Carrier Transport in CsPbBr3 Single Crystals for High-Performance X-Ray Detection.

The direct band gap CsPbBr3 perovskite is regarded as a promising alternative for low-cost and high-performance X-ray radiation detectors. Despite the fact that CsPbBr3 nanocrystals have been shown to be good scintillators in the indirect conversion mode, the direct X-ray conversion with CsPbBr3 single crystals is expected to yield higher spatial resolution. Here, rubidium (Rb) doping is demonstrated to be an efficient approach to improve carrier transport and X-ray detection performance in the direct-conversion X-ray detectors based on Cs(1-x)RbxPbBr3 single crystals. Electrical properties' characterizations as combined with X-ray photoelectron spectroscopy (XPS) measurements have revealed that Rb doping in Cs(1-x)RbxPbBr3 single crystals can enhance the atomic interaction and orbital coupling between Pb and Br atoms, leading to an enhancement of carrier transport and X-ray detection performance. X-ray detectors based on a small amount (0.037%) of Rb-doped Cs(1-x)RbxPbBr3 single crystals exhibited a high X-ray sensitivity of 8097 µC Gyair-1 cm-2. This work offers a feasible strategy to improve the X-ray detection performance by chemical doping in all-inorganic perovskite X-ray detectors.

Study on a phosphorescent copper(I) complex and its oxygen-sensing performances upon polystyrene and MCM-41 matrixes.

In this paper, we synthesize a new ligand of 1-ethyl-2-(naphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (Phen-Np-Et) and its corresponding Cu(I) complex of [Cu(Phen-Np-Et)(POP)]BF(4), where POP is bis(2-(diphenylphosphanyl)phenyl) ether. The single-crystal structure, electronic nature and photophysical property of [Cu(Phen-Np-Et)(POP)]BF(4) are discussed in detail. It is found that the yellow emission from [Cu(Phen-Np-Et)(POP)]BF(4) owns a long excited state lifetime of 287 µs under pure N(2) atmosphere. Theoretical calculation on [Cu(Phen-Np-Et)(POP)](+) suggests that the emission comes from a triplet metal-to-ligand-charge-transfer excited state. Then, [Cu(Phen-Np-Et)(POP)]BF(4) are doped into two matrixes of polystyrene and MCM-41 to investigate the oxygen-sensing performance. Finally, sensitivity maxima of 9.6 and 3.6 are achieved by the composite nanofibers of [Cu(Phen-Np-Et)(POP)]BF(4)/polystyrene and the [Cu(Phen-Np-Et)(POP)]BF(4)/MCM-41, respectively. Both samples are highly sensitive toward molecular oxygen, owing to the large surface-area-to-volume ratios of nanofibrous membranes and MCM-41 matrix.

Adsorption of cationic polyelectrolyte at the solid/liquid interface and dispersion of nanosized silica in water.

Adsorption of cationic polyelectrolyte, a homopolymer of maleimide propyl trimethylammonium chloride (MPTMAC), on silica nanoparticles from aqueous solution was studied. The adsorbed amount of MPTMAC and the adsorption layer thickness from solutions of different pH, polyelectrolyte concentration, salt type, and salt concentration were measured. The adsorbed amount exhibited a maximum as a function of the electrolyte concentration. The onset of the decline in the adsorbed amount depended on the type of counterions. The thickness of the adsorption layer increased gradually with increased of electrolyte concentration and leveled off at high electrolyte concentration. The enhanced adsorption in the presence of Na2SO4 can be explained by the bivalent SO4(2-) causing a better shielding effect. With increasing pH the adsorbed amount of MPTMAC increased, whereas the thickness of an adsorbed layer of MPTMAC decreased. At low polyelectrolyte concentrations unstable silica suspensions were observed from a stability test. At high polyelectrolyte concentrations the higher particle coverage caused electrosteric stabilization of the dispersion. However, further increase in MPTMAC concentration after saturated adsorption would flocculate the dispersed system. At low pH, MPTMAC tending to create a loops or tails conformation stabilized the suspension.

Adsorption of poly(acrylic acid) onto the surface of titanium dioxide and the colloidal stability of aqueous suspension.

The adsorption of poly(acrylic acid) (PAA) in aqueous suspension onto the surface of TiO(2) nanoparticles was investigated. FTIR spectroscopic data provided evidence in support of hydrogen bonding and chemical interaction in the case of the PAA-TiO(2) system. Adsorption isotherms demonstrated that part of the PAA initially added to the suspension was adsorbed onto the TiO(2) surface, after which there was a gradual attainment of an adsorption plateau. The adsorption density of PAA was found to increase with an increase of PAA molecular weight, while it decreased with an increase of pH. The thickness of the PAA adsorption layer was calculated based on measurements of suspension viscosities in the absence and presence of PAA. It was shown that the thickness of the adsorption layer increased with the increase of pH, PAA molecular weight, and its concentration. The surface charge density, the diffuse charge density, and the zeta potential of TiO(2) varied distinctly after PAA adsorption. The shift of pH(iep) toward a lower pH value was observed in the presence of PAA. PAA was found to stabilize the suspension of TiO(2) nanoparticles through electrosteric repulsion. The influence of factors such as PAA molecular weight and its concentration on the colloidal stability of the aqueous suspension was also investigated.