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Nanoparticle (NP) interactions with cells and organisms are mediated by a biomolecular adsorption layer, the so‐called “protein corona.” An in‐depth understanding of the corona is a prerequisite to successful and safe application of NPs in biology and medicine. In this work, earlier in situ investigations on small NPs are extended to large polystyrene (PS) NPs of up to 100 nm diameter, using human transferrin (Tf) and human serum albumin (HSA) as model proteins. Direct NP sizing experiments reveal a reversibly bound monolayer protein shell (under saturating conditions) on hydrophilic, carboxyl‐functionalized (PS‐COOH) NPs, as was earlier observed for much smaller NPs. In contrast, protein binding on hydrophobic, sulfated (PS‐OSO3H) NPs in solvent of low ionic strength is completely irreversible; nevertheless, the thickness of the observed protein corona again corresponds to a protein monolayer. Under conditions of reduced charge repulsion (higher ionic strength), the NPs are colloidally unstable and form large clusters below a certain protein–NP stoichiometric ratio, indicating that the adsorbed proteins induce NP agglomeration. This comprehensive characterization of the persistent protein corona on PS‐OSO3H NPs by nanoparticle sizing and quantitative fluorescence microscopy/nanoscopy reveals mechanistic aspects of molecular interactions occurring during exposure of NPs to biofluids.

In this work, we report a robust Ru phosphide (RuP) catalyst, which exhibits high propylene selectivity for propane dehydrogenation, whereas monometallic Ru nanoparticles (NPs) result in cracking. X-ray photoelectron spectroscopy, synchrotron X-ray absorption spectroscopy, transmission CO-IR of the reduced catalyst, and high-angle annular dark-field scanning transmission electron microscopy are used to identify the surface structure of NPs with different P/Ru atomic ratios, changing from Ru to Ru2P to RuP with increasing P loading. In addition to improving the olefin selectivity, increasing the P/Ru ratio leads to higher turnover rates and lowers the deactivation rate. P is thought to act as a structural promoter to reduce the Ru ensemble size, decreasing the hydrogenolysis rate. In addition, increasing the P/Ru ratio leads to a decrease in the energy of the Ru valence orbitals, which are suggested to weaken metal-adsorbate bond energies and reactant surface coverages.

Efficient photon harvesting materials require easy-to-deposit materials exhibiting good absorption and excited-state transport properties. We demonstrate an organic thin-film material system, a palladium-porphyrin based surface-anchored metal-organic framework (SURMOF) thin film, that meets these requirements. Systematic investigations using transient absorption spectroscopy confirm that triplets are very mobile within single crystalline domains; a detailed analysis reveals a triplet transfer rate on the order of 10 10 s-1. The crystalline nature of the SURMOFs also allows a thorough theoretical analysis using density functional theory (DFT). The theoretical results reveal that the intermolecular exciton transfer can be described by a Dexter electron exchange mechanism that is considerably enhanced by virtual charge-transfer exciton intermediates. Based on the photophysical results, we predict exciton diffusion lengths on the order of several micrometers in perfectly ordered, single-crystalline SURMOFs. In the presently available samples, strong interactions of excitons with domain boundaries present in these metal-organic thin films limit the diffusion length to the diameter of these two-dimensional grains, which amount to about 100 nm. These results demonstrate potential of SURMOFs for energy harvesting applications.

BackgroundThe Traditional Chinese Medicine, arsenic trioxide (ATO, As2O3) could inhibit growth and induce apoptosis in a variety of solid tumor cells, but it is severely limited in the treatment of glioma due to its poor BBB penetration and nonspecifcity distribution in vivo.PurposeThe objective of this study was encapsulating ATO in the modified PAMAM den-drimers to solve the problem that the poor antitumor effect of ATO to glioma, which provide a novel angle for the study of glioma treatment.MethodsThe targeting drug carrier (RGDyC-mPEG-PAMAM) was synthesized based on Arg-Gly-Asp (RGDyC) and αvβ3 integrin targeting ligand, and conjugated to PEGylated fifth generation polyamidoamine dendrimer (mPEG-PAMAM). It was characterized by nuclear magnetic resonance, fourier transform infrared spectra, Nano-particle size-zeta potential analyzer,etc. The in vitro release characteristics were studied by dialysis bag method. MTT assay was used to investigate the cytotoxicity of carriers and the antitumor effect of ATO formulation. In vitro blood-brain barrier (BBB) and C6 cell co-culture models were established to investigate the inhibitory effect of different ATO formulation after transporting across BBB. Pharmacokinetic and antitumor efficacy studies were investigated in an orthotopic murine model of C6 glioma.ResultsThe prepared RGDyC-mPEG-PAMAM was characterized for spherical dendrites, comparable size (21.60±6.81 nm), and zeta potential (5.36±0.22 mV). In vitro release showed that more ATO was released from RGDyC-mPEG-PAMAM/ATO (79.5%) at pH 5.5 than that of pH 7.4, during 48 hours. The cytotoxicity of PEG-modified carriers was lower than that of the naked PAMAM on both human brain microvascular endothelial cells and C6 cells. In in vitro BBB model, modification of RGDyC heightened the cytotoxicity of ATO loaded on PAMAM, due to an increased uptake by C6 cells. The results of cell cycle and apoptosis analysis revealed that RGDyC-mPEG-PAMAM/ATO arrested the cell cycle in G2-M and exhibited threefold increase in percentage of apoptosis to that in the PEG-PAMAM/ATO group. Compared with ATO-sol group, both RGDyC-mPEG-PAMAM/ATO and mPEG-PAMAM/ATO groups prolonged the half-life time, increased area under the curve, and improved antitumor effect, significantly. While the tumor volume inhibitory of RGDyC-mPEG-PAMAM/ATO was 61.46±12.26%, it was approximately fourfold higher than the ATO-sol group, and twofold to the mPEG-PAMAM/ATO group.ConclusionIn this report, RGDyC-mPEG-PAMAM could enhance the antitumor of ATO to glioma, it provides a desirable strategy for targeted therapy of glioma.

New nano-sized carbon dioxide (CO2) adsorbents based on Halloysite nanotubes impregnated with polyethylenimine (PEI) were designed and synthesized, which were excellent adsorbents for the capture of CO2 at room temperature and had relatively high CO2 adsorption capacity. The prepared adsorbents were characterized by various techniques such as Fourier transform infrared spectrometry, gel permeation chromatography, dynamic light scattering, thermogravimetry, thermogravimetry-Fourier transform-infrared spectrometry, scanning electron microscopy and transmission electron microscopy. The adsorption characteristics and capacity were studied at room temperature, the highest CO2 adsorption capacity of 156.6 mg/g-PEI was obtained and the optimal adsorption capacity can reach a maximum value of 54.8 mg/g-adsorbent. The experiment indicated that this kind of adsorbent has a high stability at 80°C and PEI-impregnated adsorbents showed good reversibility and stability during cyclic adsorption-regeneration tests.

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Precise control of elemental configurations within multimetallic nanoparticles could enable access to functional nanomaterials with significant performance benefits. Here, we present a one-pot synthesis of supported Ag@PdAg core-shell catalyst with an ordered PdAg alloy shell and an Ag core. Both the relative reduction potential and ratio of metal precursors are essential for this synthesis strategy. The distinguished properties of Ag@PdAg, particularly the electronic structure, indicates the existence of electron modification not only between Pd and Ag on PdAg shell, but between Ag core and alloy shell. The Ag@PdAg catalyst displays 97% ethene yield in the partial hydrogenation of acetylene, which is 2.0 and 8.1 times that of over PdAg alloy and pure Pd catalysts, and this is the most selective catalyst reported to data under industrial evaluation conditions. Moreover, this core-shell structure exhibits preferable stability with comparison to PdAg alloy catalyst. The facile synthesis of core-shell architecture with alloy shell structure provides a new platform for efficient catalytic transfer of chemical resource.