Latest ArticlesAchieving high activity and durability for the oxygen reduction reaction (ORR) with an ultra-low amount of platinum is significant to promote the widespread application of proton exchange membrane fuel cells (PEMFCs). Here we report a new ultrathin (~1 nm) ternary PtNiGa alloy nanowires (PtNiGa NWs) electrocatalyst, in which the presence of gallium (Ga) enhances the oxidation resistance of platinum (Pt) and nickel (Ni) and suppresses the dissolution of Ni. The mass and specific activities of PtNiGa NWs are about 11.2 and 7.6 times higher than those of commercial Pt/C catalysts for ORR. Moreover, the mass activity of PtNiGa/C NWs nanocatalyst decreased only by 12.8% and largely retained its electrochemical surface area (ECSA) after 10,000 potential cycles, compared with 38% loss of ECSA for commercial Pt/C catalyst. Therefore, this work provides a general guideline for preparing ternary alloy electrocatalysts and enhancing the activity and stability of the cathode ORR reaction of PEMFCs.
After a century of standstill, bacteria-based tumor therapy has resurged recently benefiting from the revolution of tumor immunotherapy, which provides unique solutions to tackle the obstacles of traditional tumor treatments. Obligate and facultative anaerobes with active tropism can selectively colonize at tumor sites and suppress tumor growth via different mechanisms, serving as attractive tools for tumor treatment either as a monotherapy or combining with other therapies for synergistic anti-tumor effects. In this critical review, we introduce the recent advances of bacteria-based tumor therapy from the following aspects. First, the general properties of bacteria are reviewed emphasizing on their structural components related to tumor immunotherapy, and the main bacteria that have been used in tumor therapy are listed. Then, the benefits of bacteria for tumor therapy are illustrated, such as tumor targetability, deep penetration, and facile genetic engineering for attenuation, enhanced efficacy, as well as bioimaging. Next, anti-tumor mechanisms of bacteria are summarized, which refer to intrinsic tumoricidal activities, immune activation, bacteria metabolism, and their capability to regulate gut microbiota homeostasis. Moreover, bacteria could act as carriers to deliver various types of therapeutics to achieve combination therapy with improved efficacy. In addition, several challenges for anti-tumor applications of bacteria are discussed regarding the delivery, efficacy and safety issues, and potential solutions are also provided. Finally, the possible improvements and perspectives are discussed in the end, which provide a guideline for the design of advanced bacteria-based tumor therapeutics in the future.
We report a facile template-free fabrication of heterostructured Co3O4/CuO hollow nanospheres using pre-synthesized Co/Cu-glycerate as conformal precursor. The introduction of copper nitrate in the solvothermal reaction system of glycerol/isopropanol/cobalt nitrate readily induces the conversion from solid Co-glycerate to hollow Co/Cu-glycerate nanospheres, and the effect of the Co/Cu atomic ratio on the structure evolution of the metal glycerates as well as their corresponding oxides were investigated. When examined as anode materials for lithium-ion batteries, the well-defined Co3O4/CuO hollow nanospheres with Co/Cu molar ratio of 2.0 demonstrate excellent lithium storage performance, delivering a high reversible capacity of 930 mAh/g after 300 cycles at a current density of 0.5 A/g and a stable capacity of 650 mAh/g after 500 cycles even at a higher current density of 2.0 A/g, which are much better than their counterparts of bare CuO and Co3O4. The enhanced lithium storage performance can be attributed to the synergistic effect of the CuO and Co3O4 heterostructure with hollow spherical morphology, which greatly enhances the charge/electrolyte transfer and effectively buffers the volume changes upon lithiation/delithiation cycling.
An atom economic β-C(sp3)−H chlorination of amide derivatives has been developed. This mild protocol employs CuCl2 instead of palladium catalysts with atom-economic HCl as chlorine sources and enables the late-stage functionalization of medicine derivatives. Mechanism studies suggest a plausible visible light triggered ligand-to-metal charge transfer (LMCT)/1,4-hydrogen atom transfer (HAT) cascade.
Patients with epidermal growth factor receptor (EGFR) wild-type non-small cell lung cancer (NSCLC) often show primary resistance to gefitinib therapy. It is thus necessary to study the metabolism of gefitinib in NSCLC cells to comprehensively reveal the reasons for the primary resistance of tumors. Herein, we develop a platform for studying drug metabolism heterogeneity based on single-cell mass spectrometry (sDMH-scMS) by integrating living-cell electrolaunching ionization MS (ILCEI-MS) and high-performance liquid chromatography-MS (HPLC-MS) analysis, and the primary resistance of NSCLC cells to gefitinib was studied using this platform. The ILCEI-MS analysis showed that approximately 11.9% of NSCLC single cells contained the gefitinib metabolite M11; HPLC-MS detection diluted the intensity of M11 in subpopulations and concealed the heterogeneity of drug metabolism in tumor single cells. The intensity of gefitinib in EGFR wild-type A549 cells was markedly lower than in mutant PC9 cells, and the intensity of gefitinib metabolites was significantly higher than in PC9 cells, suggesting that the primary resistance of NSCLC cells is related to gefitinib metabolism. Moreover, the combination of gefitinib and the drug-metabolizing enzyme inhibitor α-naphthoflavone was shown to overcome the primary resistance of the NSCLC cells. Overall, the results of this study are expected to be applicable for clinical drug resistance diagnosis and treatment at the single-cell level.
Vacancy engineering and Mott-Schottky heterostructure can accelerate charge transfer, regulate adsorption energy of reaction intermediates, and provide additional active sites, which are regarded as valid means for improving catalytic activity. However, the underlying mechanism of synergistic regulation of interfacial charge transfer and optimization of electrocatalytic activity by combining vacancy and Mott-Schottky junction remains unclear. Herein, the growth of a bifunctional NiCo/NiCoP Mott-Schottky electrode with abundant phosphorus vacancies on foam nickel (NF) has been synthesized through continuous phosphating and reduction processes. The obtained NiCo/NiCoP heterojunctions show remarkable OER and HER activities, and the overpotentials for OER and HER are as low as 117 and 60 mV at 10 mA/cm2 in 1 mol/L KOH, respectively. Moreover, as both the cathode and anode of overall water splitting, the voltage of the bifunctional NiCo/NiCoP electrocatalyst is 1.44 V at 10 mA/cm2, which are far exceeding the benchmark commercial electrodes. DFT theoretical calculation results confirm that the phosphorus vacancies and build-in electric field can effectively accelerate ion and electron transfer between NiCo alloy and NiCoP semiconductor, tailor the electronic structure of the metal centers and lower the Gibbs free energy of the intermediates. Furthermore, the unique self-supported integrated structure is beneficial to facilitate the exposure of the active site, avoid catalyst shedding, thus improving the activity and structural stability of NiCo/NiCoP. This study provides an avenue for the controllable synthesis and performance optimization of Mott-Schottky electrocatalysts.
Rare earth luminescence has attracted widespread attention for several decades, among which near-infrared (NIR) light-related up-conversion luminescence and NIR-Ⅱ luminescence are widely used in the biomedical field. The NIR-related luminescence is widely studied due to the excellent performance, such as good biocompatibility, deep tissue penetration depth, low self-fluorescence and minimal light damage to organisms. In this review, we mainly introduce the mechanism for rare earth up-conversion luminescence, NIR-Ⅱ luminescence and conclude their advantages compared with traditional luminescence. These excellent priorities provide the basis for NIR-related luminescence bioimaging in vivo. Additionally, we hilglight the scheme for the sensitive detection of substances in organisms and various methods for biological therapy. In spite of the existing research, it is outlined that NIR-related luminescence has great potential to be applied in different aspects, expanding perspectives and future challenges of research in related fields. Based on the current scientific achievements, this review can provide reference for research in the areas mentioned above, expand the research direction and arouse a broad interest in different disciplines to pay attention to rare earth luminescence.
Stimuli-responsive smart materials exhibit reverse chemical/physical changes in response to external stimuli and research on stimuli-responsive smart materials with self-powered properties is still uncultivated ground. Here, we report perovskite crystalline self-powered multiple stimuli-responsive materials triggered by chemical and thermal stimuli. [HMEP]PbI3·(H2O) (1; HMEP is a hydroxytris(1-methylethyl)phosphorus cation) crystallizes in a chiral space group P21 at 293 K and has the piezoelectric reaction (d33 = 10 pC/N and output voltage = 1 V) of self-powered modes, this value is larger than the value of 3 pC/N for the classical piezoelectric material ZnO. Piezoelectric materials can generate energy due to mechanical deformation, and using thermal heating to lose water, [HMEP]PbI3 (2) can be obtained. 2 crystallizes in the non-centrosymmetric space group, undergoes two reversible phase transitions at 243/255 K and 315/348 K, and shows second harmonic generation switching. Interestingly, 2 can return to the hydrated form 1 after absorbing water. This work will lay the foundation for self-powered stimuli-responsive compounds and contribute to the construction of novel organic-inorganic hybrid materials with second harmonic generation switching.
Immune checkpoint inhibitors (ICIs) therapy targeting programmed cell death ligand 1 (PD-L1) and programmed death protein 1 (PD-1) had exhibited significant clinical benefits for cancer treatment such as triple negative breast cancer (TNBC). However, the relatively low anti-tumor immune response rate and ICIs drug resistance highlight the necessity of developing ICIs combination therapy strategies to improve the anti-tumor effect of immunotherapy. Herein, the immunomodulator epigallocatechin gallate palmitate (PEGCG) and the immunoadjuvant metformin (MET) self-assembled into tumor-targeted micelles via hydrogen bond and electrostatic interaction, which encapsulated the therapeutic agents doxorubicin (DOX)-loaded PEGCG-MET micelles (PMD) and combined with ICIs (anti-PD-1 antibody) as therapeutic strategy to reduce the endogenous expression of PD-L1 and improve the tumor immunosuppressive microenvironment. The results presented that PMD integrated chemotherapy and immunotherapy to enhance antitumor efficacy in vitro and in vivo, compared with DOX or anti-PD-1 antibody for the therapy of TNBC. PMD micelles might be a potential candidate, which could remedy the shortcomings of antibody-based ICIs and provide synergistic effect to enhance the antitumor effects of ICIs in tumor therapy.
Microfluidic combined with magnetic field have been demonstrated to be the promising solutions for fast and low-damage particles separation. However, the difficulties in the precise layout of magnets and accurate prediction of particle trajectories lead to under and over separation of target particles. A novel particle separation lab-on-chip (LOC) prototype integrated with microstructures and micropolar arrays is designed and characterized. Meanwhile, a numerical model for the separation of magnetic particles by the synergistic effect of geometry-induced hydrodynamics and magnetic field is constructed. The effect of geometry and magnetic field layout on particle deflection is systematically analyzed to implement accurate prediction of particle trajectories. It is found that the separation efficiency of magnetic particles increased from 50.2% to 91.7% and decreased from 88.6% to 85.7% in the range of depth factors from 15 µm to 27 µm and width factors from 30 µm to 60 µm, respectively. In particular, the combined effect of the offset distance of permanent magnets and the distance from the main flow channel exhibits a significant difference from the conventional perception. Finally, the developed LOC prototype was generalized for extension to arbitrary systems. This work provides a new insight and robust method for the microfluidic separation of magnetic particles.
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