摘要 : Three-dimensional sponge-architecture covalent organic frameworks (COFs)-aerogel was successfully designed and synthesized via a freeze-drying template approach, and utilized as an efficient sorbent in solid-phase extraction (SPE). A method for selective enrichment of pharmaceutical contaminants including tetracycline, chlortetracycline, methacycline and oxytetracycline in the environment and food samples was proposed by combining with high performance liquid chromatography (HPLC). To understand the adsorption mechanism, selectivity test and molecular dynamics (MD) simulated calculation were both carried out. The experimental and in-silico results demonstrated that the COFs-aerogel possessed high selectivity for contaminants with H bond acceptors/donors and good efficiency with maximum adsorption capacity up to 294.1 mg/g. The SPE-based HPLC method worked well in the range of 8–1000 ng/mL, with the need of little dose of adsorbent and sample volume while no need of spectrometer, outgoing the reported adsorbents. Under the optimized conditions, the intra-day and inter-day relative standard deviations (RSD) of repeatability were within 2.78–6.29 % and 2.44–8.42 % (n = 5). The results meet the current detection requirement for practical applications, and could be extended for further design of promising adsorbents.

摘要 : The main challenges (sluggish electron transfer, low energy density) hinder the future application of enzymatic biofuel cells (EBFCs), which urgent to take effective measures to solve these issues. In this work, a composite of Au nanoparticles decorated graphdiyne (AuNPs@GDY) is fabricated and employed as the carrier of enzyme (G6PDH), and a mechanism based on π-π interaction of electron transfer is proposed to understand bioelectrocatalysis processes. The results show that the AuNPs@GDY composite exhibits the highest current density among the three materials (GDY, AuNPs, and AuNPs@GDY), which is 3.4 times higher than that of GDY and 2.5 times higher than that of AuNPs. Furthermore, the results reveal that the AuNPs could increase the loading of enzymes and provide more active site for reaction, while GDY provides highly π-conjugated structure and unique sp/sp 2 -hybridized linkages interface. This work provides new insights to explore a theoretical basis for the development of more efficient bioelectrocatalytic systems.

摘要 : DNA methyltransferase is significant in cellular activities and gene expression, and its aberrant expression is closely linked to various cancers during initiation and progression. Currently, there is a great demand for reliable and label-free techniques for DNA methyltransferase evaluation in tumor diagnosis and cancer therapy. Herein, a low-background fluorescent RNA aptamer-based sensing approach for label-free quantification of cytosine-guanine (CpG) dinucleotides methyltransferase (M.SssI) is reported. The fluorogenic light-up RNA aptamers-based strategy exhibits high selectivity via restriction endonuclease, padlock-based recognition, and RNA transcription. By combining rolling circle amplification (RCA), and RNA transcription with fluorescence response of RNA aptamers of Spinach-dye compound, the proposed platform exhibited efficiently ultrahigh sensitivity toward M.SssI. Eventually, the detection can be achieved in a linear range of 0.02–100 U mL−1 with a detection limit of 1.6 × 10−3 U mL−1. Owing to these superior features, the method is further applied in serum samples spiked M.SssI, which delivers a recovery ranging from 92.0 to 107.0% and a relative standard deviation <7.0%, providing a promising and practical tool for determining M.SssI in complex biological matrices.

摘要 : The active component of copper-based materials for electrocatalytic nitrate reduction to ammonia (NRA) remains unclear due to the susceptibility of oxidation of copper. Using density functional theory calculations, NRA pathways are evaluated on low-index crystal surfaces Cu2O (111), CuO (111), and Cu (111) at different pH. Cu2O (111), with abundant undercoordinated Cu atoms on the surface, shows easier adsorption of NO3– than Cu (111) or CuO (111). NRA on CuO (111) is hindered by the large ΔG of adsorption of NO3– and hydrogenation of NO. Thus, Cu (111) and Cu2O (111) contribute most to the NRA activity while CuO (111) is inert. Three key steps of NRA on copper-based catalysts are identified: adsorption of NO3–, NO → NOH/ NHO, and NH3 desorption, as the three can be rate-determining steps depending on the local environment. Moreover, previous experimentally detected NH2OH on copper-based catalysts may come from the NRA on Cu2O (111) as the most probable pathway on Cu2O (111) is NO3– → NO3 → NO2 → NO → NHO → NHOH → NH2OH → NH2 → NH3 → NH3(g). At high reduction potential, CuOx would be reduced into Cu, so the effective active substance for NRA in a strong reduction environment is Cu.

摘要 : Exploring accurate, noninvasive, and inexpensive disease diagnostic sensors is a critical task in the fields of chemistry, biology, and medicine. The complexity of biological systems and the explosive growth of biomarker data have driven machine learning to become a powerful tool for mining and processing big data from disease diagnosis sensors. With the development of bioinformatics and artificial intelligence (AI), machine learning models formed by data mining have been able to guide more sensitive and accurate molecular computing. This review presents an overview of big data collection approaches and fundamental machine learning algorithms and discusses recent advances in machine learning and molecular computational disease diagnostic sensors. More specifically, we highlight existing modular workflows and key opportunities and challenges for machine learning to achieve disease diagnosis through big data mining.

摘要 : Point-of-care testing (POCT) has attracted great interest because of its prominent advantages of rapidness, precision, portability, and real-time monitoring, thus becoming a powerful biomedical device in early clinical diagnosis and convenient medical treatments. However, its complicated manufacturing process and high expense severely impede mass production and broad applications. Herein, an innovative but inexpensive integrated sandwich-paper three-dimensional (3D) cell sensing device is fabricated to in situ wirelessly detect H2O2 released from living cells. The paper-based electrochemical sensing device was constructed by a sealed sandwiched bottom plastic film/fiber paper/top hole-centered plastic film that was printed with patterned electrodes. A new (Fe, Mn)3(PO4)2/N-doped carbon nanorod was developed and immobilized on the sensing carbon electrode while cell culture solution filled the exposed fiber paper, allowing living cells to grow on the fiber paper surrounding the electrode. Due to the significantly shortening diffusion distance to access the sensing sites by such a unique device and a rationally tuned ratio of Fe2+/Mn2+, the device exhibits a fast response time (0.2 s), a low detection limit (0.4 μM), and a wide detection range (2–3200 μM). This work offers great promise for a low-cost and highly sensitive POCT device for practical clinic diagnosis and broad POCT biomedical applications.

摘要 : Regulating the electronic and geometric structures of electrocatalysts is an effective strategy to boost their catalytic properties. Herein, a coral-like nanostructure is assembled with Mo-doped Pt clusters to form a highly active catalyst toward the oxygen reduction reaction (ORR). The advantages of a Mo-doped porous skeleton, grain boundaries, and MoOx species on the Pt cluster surfaces synergistically boost the electrocatalytic performance. This unique architecture delivers 3.5- and 2.8-fold higher mass and specific activities, respectively, than commercial Pt/C. Density functional theory calculations reveal that the Mo-doped Pt clusters have an optimized Pt–O bond length of 2.110 ​Å, which weakens the adsorption energy of the intermediate O∗ to yield great ORR activity. Moreover, the catalyst shows a decay in the half-wave potential of only 8 ​mV after 10, 000 cycles of accelerated durability testing. The high stability arises from the increased dissociation energy of Pt atoms and the stable architecture of the coral-like structure of clusters.

摘要 : Efficient water splitting electrocatalysts with low cost is essential for the development of sustainable hydrogen energy . Ni foam supported Ru-doped NiCoP nanowire arrays (Ru–NiCoP@NF) are synthesized via a hydrothermal reaction followed by low-temperature phosphorization. The as-obtained Ru–NiCoP@NF exhibits outstanding bifunctional catalytic activity, achieving 100 mA cm −2 at the overpotentials of 108 and 264 mV for HER and OER, respectively, with a tiny loading of Ru (≈61.8 μg cm −2 ). The electrolyzer assembled using Ru–NiCoP@NF as the bifunctional electrode requires 1.62 V (with no iR correction) for 50 mA cm −2, 50 mV lower than RuO 2 –Pt/C based electrolyzer. The enhancement of Ru–NiCoP@NF is ascribed to Ru dopants, which contribute to formation of 3D nanowire arrays with the advantages of exposing sufficient active sites, accelerating charge transfer and outstanding mechanical strength . More importantly, the Ru atoms in NiCoP successfully modulate the charge densities around Ni, Co and P through strong electronic interaction, thus elevating the sluggish Volmer step for HER and promoting the adsorption capacity of oxygen-containing intermediates for OER.

摘要 : Synthesis of nontoxic quantum dots (QDs) with excellent optical properties in aqueous phase to replace organic dyes with photobleaching drawbacks used in bioimaging has become a research priority. Herein, water-soluble Ag-In-Zn-S (AIZS) QDs were prepared by microwave-assisted hydrothermal method at 110 °C for 40 min. The luminescence peak of AIZS QDs was varied from 684.5 nm to 576.2 nm when the Ag/In molar ratio was changed in the range of 1/2–1/10. A clear blue-shift of PL peak from 616.8 nm to 551.5 nm was observed with increasing Zn 2+ element with the Ag/Zn molar ratio in the range of 1/0–1/14, indicating that the increase of Zn 2+ content caused the increase of band gap. The AIZS QDs exhibit the highest photoluminescent quantum yield (PLQY) of 20.67 % with the molar ratio of Ag/In/Zn=1/6/2, and fluorescence lifetime upped to 294.69 ns. Finally, human hepatocellular carcinomas (HepG2) cells and Hela cells were incubated with AIZS QDs solution at different concentrations and were found to have a high survival rate. Furthermore, HepG2 cells emitted bright yellow light when stimulated upon UV excitation, indicating that AIZS QDs can be applied in bioimaging field.

摘要 : Magnetic two-dimensional nanocomposites (M2D NCs) that synergistically combine magnetic nanomedicine and 2D nanomaterials have emerged in multimodal antitumor therapy, attracting great interest in materials science and biomedical engineering. This review provides a summary of the recent advances of M2D NCs and their multimodal antitumor applications. We first introduce the design and fabrication of M2D NCs, followed by discussing new types of M2D NCs that have been recently reported. Then, a detailed analysis and discussions about the different types of M2D NCs are presented based on the structural categories of 2D NMs, including 2D graphene, transition metal dichalcogenides (TMDs), transition metal carbides/nitrides/carbonitrides (MXenes), black phosphorus (BP), layered double hydroxides (LDHs), metal organic frameworks (MOFs), covalent organic frameworks (COFs) and other 2D nanomaterials. In particular, we focus on the synthesis strategies, magnetic or optical responsive performance, and the versatile antitumor applications, which include magnetic hyperthermia therapy (MHT), photothermal therapy (PTT), photodynamic therapy (PDT), drug delivery, immunotherapy and multimodal imaging. We conclude the review by proposing future developments with an emphasis on the mass production and biodegradation mechanism of the M2D NCs. This work is expected to provide a comprehensive overview to researchers and engineers who are interested in such a research field and promote the clinical translation of M2D NCs in practical applications.