Latest ArticlesAs a member of the curcuminoid compound family, curcumin (Cur) has many interesting therapeutic properties. However, its low aqueous solubility and stability have resulted in poor bioavailability and restricted clinical efficacy. Based on size matching, β-cyclodextrin polymer (β-CDP), with its hydrophilic polymer chains and hydrophobic cavities, can form an inclusion complex with Cur. To improve the water solubility and stability of Cur, a simple and eco-friendly grinding method was designed to form β-CDP inclusion complexes. According to the Boltzmann–Hamel's method and Job's method, the molar ratio of the β-CD unit in β-CDP to Cur was determined to be 1 : 1. The diffusion coefficient and diffusion activation energy of Cur-β-CDP were calculated in an electrochemical study. This supramolecular complex worked well in vitro to inhibit the proliferation of hepatoma carcinoma cells HepG2. Remarkably, this method visibly reduced the undesirable side effects on normal cells, without weakening the anti-cancer activity of the drugs. We expect that the obtained host–guest complex will provide a new approach for delivering natural drug molecules, having low water solubility.
Constructing molecule@support composites is an attractive strategy to realize heterogeneous molecular electrocatalysis. Herein, we synthesized metal-organic framework (MOF)-supported molecular catalysts for hydrogen evolution and oxygen reduction reaction (HER/ORR). Ligand exchange strategy was used to prepare molecule@support hybrids due to the same functional group. A series of hybrids were obtained using Co porphyrin (1) and different MOFs including MIL-88(Fe), MOF-5(NiCo) and UIO-66(Zr). The 1@MOF-5(NiCo) had the best HER and ORR activity compared with 1@MIL-88(Fe) and 1@MOF-5(NiCo). These hybrids also exhibited tunable selectivity for ORR with four-electron process, which can be attributed to the synergistic effect of porphyrin molecules and MOFs. This work provides a possibility for molecular catalysts to improve activity of HER and tune selectivity of ORR.
Dielectric elastomers (DEs) have drawn much attention owing to their application prospects in artificial muscles and soft robotics, it is still a big challenge to prepare DEs with high electromechanical performances. This work reports a highly stretchable poly(thioether)-b-polysiloxane-b-poly(thioether) triblock copolymer based homogenous DEs with high electromechanical properties. The triblock copolymer (PSiPGE) was synthesized through the ring-opening polymerization (ROP) of phenyl glycidyl ether (PGE) and carbonyl sulfide (COS) catalyzed by silicon alkoxides. The dipoles (benzene rings) on the side groups of PSiPGE improved the dipole polarizations and the phase separation structure of this triblock copolymer enhanced the interfacial polarizations between poly(thioether) and polysiloxane, and thus improving the dielectric constant (ε', up to 5.8). In addition, the PSiPGE exhibited low elastic modulus (Y, 0.04 MPa), and thus possessed high electromechanical sensitivity (β, ~145 MPa−1) which is much higher than that of most homogenous DEs. This work provides a new strategy to construct homogenous DEs with excellent electromechanical performances, leading to a greater application aspect in the actuated devices.
Surface engineering that could modulate the surface shape to be endowed with the high specific surface ratio, abundant chemical dangling bonds and improved defects exposure is highly desired and needs further exploring. Here, we report a facile strategy of surface engineering on decorating the controllable segmented copper-iron nanowires arrays (Cu-Fe NWs) with their respective hydroxides. Specifically, the pristine segmented Cu-Fe NWs are firstly synthesized via sequentially electrodepositing Cu NWs and Fe NWs inside the nanochannels of anode aluminum oxide (AAO) template. Subsequently, the surface and interface of Cu-Fe NWs are wet-chemically etched, in which the metallic Cu and Fe are partially converted into Cu(OH)x nano-fibrous roots (NFRs) and FeO(OH)y nanoparticles (NPs), and finally decorate around the respective outer-surface of Cu NWs and Fe NWs segments. As one case of the applications in hydrogen evolution reaction (HER), our surface-modified Cu-Fe NWs exhibit improved catalytic activity compared with Fe NWs.
Developing efficient and inexpensive OER electrocatalysts is a challenge for overall water splitting. Herein, the heterostructured FeCo LDH@NiCoP/NF nanowire arrays with high performance were rationally designed and prepared using an interface engineering strategy. Benefitting from the special heterostructure between FeCo LDH and NiCoP, the as-synthesized FeCo LDH@NiCoP/NF electrocatalyst exhibits outstanding OER performance with an exceptionally low overpotential of 206 mV to achieve 20 mA/cm2 current density in an alkaline electrolyte. Importantly, a cell constructed using the FeCo LDH@NiCoP/NF electrocatalyst as cathode and anode just needs a voltage of 1.48 V at 10 mA/cm2, and shows excellent stability over 80 h. Experimental and theoretical results verified that the introduction of NiCoP efficiently regulates the electronic structure of FeCo LDH, which tremendously boosts the conductivity and intrinsic catalytic activity of FeCo LDH@NiCoP/NF electrocatalyst. The present work provides guidance for the preparation of other efficient and cheap electrocatalytic materials.
The unveiling of MOF growth mechanism is hampered by the lack of fundamental knowledge about the very early stage of nucleation, especially the form and ratio of molecular species in the solution for crystal growth. Herein, we report the detection of growth species for a series of MOFs with mono-linker, Cu-MOF-2-BDC and Cu-MOF-2-NDC, and two linkers, MTV-MOF-2-(C4H4), by high resolution ESI-MS, where a large variety of Cu-containing species are identified unambiguously. The solvent molecules such as H2O, methanol and DMF participate in the formation of these species, other than ethanol. Furthermore, in the growth solution of MTV-MOF-2-(C4H4), growth species containing two different organic linkers are observed. The feeding ratio is not the only factor controlling the distribution of growth species for MTV-MOFs, but also the solvent involves in coordination, an aspect usually overlooked previously.
Green hydrogen production and CO2 fixation have been identified as the fundamental techniques for sustainable economy. The open challenge is to develop high performance catalysts for hydrogen evolution reaction (HER) and CO2 electroreduction (CO2ER) to valuable chemicals. Under such context, this work reported computational efforts to design promising electrocatalyst for HER and CO2ER based on the swarm-intelligence algorithm. Among the family of transition-metal phosphides (TMPs), Pt2P3 monolayer has been identified as excellent bifunctional catalysts due to high stability, excellent conductivity and superior catalytic performance. Different from typical d-block catalysts, p-band center presented by P atoms within Pt2P3 monolayer plays the essential role for its reactivity towards HER and CO2ER, underlining the key value of p-electrons in advanced catalyst design and thus providing a promising strategy to further develop novel catalysts made of p-block elements for various energy applications.
The hunt for agents that are suitable for actinide decorporation to reduce the whole-body load of actinide in accidental internal exposure is the ever-lasting goal in radiation protection and medical treatment in nuclear emergency. All current decorporation agents can be categorized as two groups, one is the molecular ligands, and the other is the nanoparticles decorated with molecular ligands. Here in this work, functional nanodiamonds (fNDs) with ssDNA (the endogenous biomacromolecule rich in phosphate groups) loaded on the NDs is reported, which poses good uranyl adsorption selectivity, high cellular uptake, fast excretion, and effective decorporation of uranyl from rat renal proximal tubular epithelial cells (NRK-52E). All those results corroborate that fNDs can potentially serve as a brand new family of chelators for actinide decorporation.
The complexation of pentavalent neptunium, Np(V), with nitrate ion in an ionic liquid solution has been studied spectroscopically for the first time. The characteristic f-f transition absorption band of Np(V) in the NIR region changes significantly upon the titration of nitrate ion into the solution, revealing strong complexation of Np(V) with nitrate ion in the ionic liquid. Most notably, the absorption band of Np(V) almost disappears when a sufficiently high concentration of nitrate ion is present in the solution. Such a rare optically "silent" species can be assigned to the 1:2 Np(V)/nitrate complex with a centrosymmetric coordination environment where Np sits at the inversion center.
Thioredoxin reductase 1 (TrxR1) is over activity in tumor cell to maintain their redox balance. Although gold clusters have great potential in antitumor drug as they could well inhibit TrxR1, the molecular mechanism has not been disclosed yet. In this work, we revealed gold clusters can well inhibit the activity of TrxR1 in lung tumor cells and further disclosed the inhibition mechanism by using computational simulation methods. We firstly inferred the binding sites of gold in the hydrophobic cavities on TrxR1. The simulation results show that the gold ion (released from Au cluster) interact with –SH of Cys189 in TrxR1, this greatly increase the distance between the C-terminal redox center of TrxR1 and the Trx redox center, thereby destroy the electron transfer pathway between them. Our electron transfer destroying mechanism is different from the previous hypothesis that gold binds to the Sec498 of TrxR1 which has never been proved by experimental and theory studies. This work provides a new understanding of the gold clusters to inhibit TrxR1 activity.
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