Latest ArticlesNitroaromatic hydrogenation catalysis without precious metals remains a longstanding challenge. The rate of electron transfer is the crucial factor affecting hydrogenation catalysis. Herein, an ionic Cd-based metal-organic framework (I-Cd-MOF) exhibiting a unique structure with one-dimensional (1D) opening nanochannels and good electron transfer ability was synthesized for catalyzing hydrogenation of 4-nitrophenol (4-NP). The catalytic activity of the unique I-Cd-MOF without noble metals is detected, which is higher than most reported noble metal catalysts. Remarkably, the reaction rate of I-Cd-MOF (4.28 min−1) is about 47.6 times higher than that of the Cd-based neutral MOF (N-Cd-MOF) with the similar crystalline structure. Liquid chromatograph mass spectrometer (LC-MS) and theoretical results demonstrate that 4-NP and five intermediates are stabilized in the channels of I-Cd-MOF, which increases the possibility of contact with H* and H2 generated at the Cd sites. The I-Cd-MOF was extended to other nitroaromatic hydrogenation catalysis, which still displays excellent activity. More importantly, the I-MOF@Filter membrane was successfully constructed for continuous hydrogenation catalytic reactions, which maintains a high catalytic performance after 7 cycles of recycling without washing. This work fills in the application of the I-MOFs in hydrogenation catalytic reactions and provides an effective way for the rapid and green degradation of nitroaromatic compounds.
Macrocyclic materials have attracted much attention due to their particular chemical and physical properties. Herein we report the precise synthesis and characterization of a new bismacrocycle structure base on cycloparaphenylene (CPP) and pillar[5]arene, named cycloparaphenylene-pillar[5]arenes (CPPn[5]). The bismacrocycle was fully characterized by NMR and HR-MS. The photophysical properties of CPPn[5] were investigated by UV–vis, and the maximum absorption peak was located at 331 nm, which was consistent with density functional theory (DFT) calculations. The fluorescence spectrum was further studied and the emission peak was maximized at 458 nm. The computational results indicate the strain energy of CPPn[5] is 27.80 kcal/mol and the HOMO-LUMO gap is 3.39 eV Notably, CPPn[5] showed interesting supramolecular properties.
N1-methyladenosine (m1A) is an important RNA modification that functions in various biological processes by interacting with cellular proteins. However, the binding proteins of N1-methyldeoxyadenosine (1mdA) in DNA remain largely unknown. Herein, we employed a quantitative proteomics strategy to identify the potential binding proteins of 1mdA in human cells. Our results revealed that serine‑threonine kinase receptor-associated protein (STRAP) can bind to 1mdA-carrying DNA. We further demonstrated that STRAP participates in alkylating agent-induced DNA damage response and can promote the repair of 1mdA embedded in DNA. Moreover, we investigated the effects of STRAP on 1mdA-induced perturbation in transcription using a shuttle vector- and next-generation sequencing-based assay, and found that STRAP is involved in the transcriptional bypass of 1mdA in human cells. Together, our study revealed STRAP as a novel 1mdA-binding protein in human cells and provided new insight into the biological implications of STRAP and 1mdA modification in human diseases.
The Wnt signaling pathway plays a critical role in bone homeostasis, and the related protein therapy strategies have been reported to have great potential in osseointegration; however, they face formidable challenges such as complex external environments and unavoidable protein denaturation. In this work, we report a novel approach combining the synthesis of metal–organic frameworks (MOFs) and protein encapsulation in a one-pot process based on zeolitic imidazolate framework-8 (ZIF-8) and Wnt3a protein, with improved biomechanical behavior and enhanced protein biological response. This combination was designed to enhance the Wnt3a protein function through the improved chemical stability provided by the ZIF-8 crystals. Additionally, the zinc ions contained in the ZIF-8 crystals induced bone homeostasis, further favoring the osteogenesis. The results showed that the Wnt3a protein-loaded ZIF-8 crystals served as efficient drug delivery vehicles to promote osteogenesis, preventing protein denaturation. In particular, Wnt3a-loaded ZIF-8 nanoparticles (Wnt3a@ZIF-8 NPs) had higher efficacy on bone marrow mesenchymal stem cells (BMSCs) than ZIF-8 NPs or Wnt3a proteins, contributing to the osteogenesis through ZIF-8 crystals and intracellular Wnt3a proteins released from Wnt3a@ZIF-8 NPs. Furthermore, polymerase chain reaction (PCR) analysis showed that the osteogenic pathways were upregulated. Overall, the present one-pot process can open up new avenues to develop signaling protein-delivery systems for applications in protein therapy strategies.
The application of photothermal therapy (PTT) is greatly limited by the low accumulation of photothermal agents, uneven photothermal distribution, and heat endurance of cancer cells. Worse still, despite PTT enhances immunogenicity, the anti-tumor immune efficacy is still unsatisfactory due to the inefficient immunogenic cell death (ICD) induction and poor infiltration of immune cells. To solve the above problems of PTT, we developed hyaluronic acid (HA) modified hollow copper sulfide nanoparticles encapsulating diethyldithiocarbamate (DDTC) to construct a breast tumor targeting and near infrared (NIR) photo-responsive drug delivery system (D-HCuS@HA), which further combined with losartan to improve the accumulation and penetration in the tumor site. Upon irradiation, D-HCuS@HA realized enhanced PTT and released cytotoxic Cu(DDTC)2 to eliminate heat endurance tumor cells, thereby enhancing anti-tumor effect and inducing effective ICD. Moreover, the combination with losartan could remodel the tumor microenvironment, allowing more T cells to infiltrate into the tumor, and significantly inhibiting the occurrence and development of metastatic tumors. In vitro/vivo results revealed the great potential of D-HCuS@HA combined with losartan, which provides a new paradigm for anti-tumor and anti-metastases.
Molecular structure of organic semiconductor plays a critical role in determining the performance and functionality of organic electronic devices, by optimizing the electrical, optical and physicochemical properties. Substituted alkyl chains are fundamental units in tailering the solubility and assemblability, among which the asymmetric properties have been reported as key element for controlling the packing motifs and intrinsic charge transport. Here, we expanded the scope of molecular asymmetry dependent sensing features based on a new series of naphthalene diimides (NDI)-based derivatives substituted with a same branching alkyl chain but various linear-shaped alkyl chains (Cn-). A clear molecular stacking change, from head-to-head bilayer to head-to-tail monolayer packing model, is observed based on the features of anisotropic molecular interactions with the change in the chain length. Most importantly, a unique LUMO level shift of 0.17 eV is validated for NDI-PhC4, providing a record sensitivity up to 150% to 0.01 ppb ammonia, due to the desired molecular reactivity and device amplification properties. These results indicate that asymmetric side-chain engineering opens a route for breath healthcare.
Sulfide oxidation under aerobic conditions can produce active oxygen for the transformation of organic pollutants in aquatic environments. However, the catalytic performance of transition metal-supported carbon material on this process is poor understood. This study found that Co-loaded carbon nanotubes (CNTs) was able to realize the efficient aerobic transformation of antibiotic ciprofloxacin (CIP) by sulfide, with the pseudo-first order reaction rate constant improved from 0.013 h−1 without catalyst to 0.44–0.71 h−1 with 100 mg/L Co-loaded CNTs. Singlet oxygen (1O2) was the main active specie playing key roles in the process of CIP aerobic transformation with presence of Co-loaded CNTs. Mechanism studies indicated that the excellent electron transfer ability of Co-loaded CNTs might play an important role to promote the electron transfer and facilitate the formation of intermediate H2O2 and 1O2. Additionally, the Co-loaded CNTs/sulfide system effectively reduced the acute toxicity of organic pollutant, and Co-loaded CNTs showed remarkable cycling stability and negligible leaching. This study gives a better understanding for the Co-loaded CNTs mediated aerobic antibiotics transformation by sulfide, and provide a reference for the application of Co-loaded carbon materials on organics aerobic transformation by sulfide.
A facile chemical method for the development of photocatalytic coating products was proposed based on practical application perspective for the Hong Kong roadside nitrogen oxides (NOx) mitigation. TiO2-based photocatalytic coating PC-C film with crystallized size of around 5–6 nm was synthesized with the peptization of H2O2. The PC-C coating possesses a super-hydrophilicity surface and is proven to have a NOx degradation rate of 46.8% with an optimum pH level of 7. In addition, the PC-C coating presents a promising photocatalytic NOx degradation compared with other commercially available coating products and P25 when applied on two building materials of poly-methyl methacrylate (PMMA) and concrete surface. A weather resistance simulation and a 180-day on-site field trial were carried out the attenuation effects of photocatalytic coating applied in outdoor exposure. Based on epidemiological estimation and field investigation, hospital admissions for respiratory diseases (HARD) and mortality cases (MC) could be reduced with the application of PC-C coating along the street canyon. This work demonstrates the feasibility of air pollution control measures for the local roadside NOx using photocatalytic technology, offering promising health benefits with environmental remediation.
It is well-established that high carbonization temperature will trigger the enzyme-like activity of carbon-based materials. However, the catalytic mechanism is still ambiguous, which hinders the further rational design of nanomaterials as enzyme mimics. Hereby, N, S-rich carbonized wool nanosheets (CWs) were synthesized at different pyrolysis temperatures. As expected, only CWs treated with high-temperature possess intrinsic oxidase- and peroxidase-like activities. Meanwhile, density functional theory (DFT) calculations demonstrate that graphitic nitrogen and the co-existence of nitrogen and sulfur in the carbon matrix serve as the active sites for the enzyme-like process. More importantly, combining theoretical calculations and experimental observations, the high-temperature triggered catalytic mechanism can be ascribed to the fact that an appropriate high-temperature maximizes the graphitization degree to a certain extent, at which most of the catalytic active sites are well retained rather than evaporating. Moreover, coupling with excellent photothermal conversion efficiency and catalytic performance, CWs can be applied to photothermal-catalytic cancer therapy under near-infrared region (NIR) light irradiation. We believe this work will contribute to understanding the catalytic mechanism of carbon-based nanozymes and promote the development of new biomedical and pharmaceutical applications.
The high specific capacity and low negative electrochemical potential of lithium metal anodes (LMAs), may allow the energy density threshold of Li metal batteries (LMBs) to be pushed higher. However, the existing detrimental issues, such as dendritic growth and volume expansion, have hindered the practical implementation of LMBs. Introducing three-dimensional frameworks (e.g., copper and nickel foam), have been regarded as one of the fundamental strategies to reduce the local current density, aiming to extend the Sand' time. Nevertheless, the local environment far from the skeleton is almost the same as the typical plane Li, due to macroporous space of metal foam. Herein, we built a double-layered 3D current collector of Li alloy anchored on the metal foam, with micropores interconnected macropores, via a viable thermal infiltration and cooling strategy. Due to the excellent electronic and ionic conductivity coupled with favorable lithiophilicity, the Li alloy can effectively reduce the nucleation barrier and enhance the Li+ transportation rate, while the metal foam can role as the primary promotor to enlarge the surface area and buffer the dimensional variation. Synergistically, the Li composite anode with hierarchical structure of primary and secondary scaffolds realized the even deposition behavior and minimum volume expansion, outputting preeminent prolonged cycling performances under high rate.
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