ANALYTICAL CHEMISTRY
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2020
·
IF 6.785
Lu Shi,Feifei Cao,Limin Zhang,Yang Tian
The development of switches responding to specific pH changes was particularly useful in wide application fields. Owing to flexible switches simulated by pH, i-motif DNAs are widely used as a pH sensor. But its character of structure transition strongly dependent on acidic pH severely hampers the application of i-motif DNA in physiological media. Herein, we report the stable i-motif structure formed at a physiological pH triggered by spatial confinement of silica nanochannels. Three classic DNA chains containing 21-mer i-motif domain base-pairs and a single-stranded multiply (T)n spacer, 5′-COOH-(T)n-CCCTAACCCTAACCCTAACCC-3′, were employed to evaluate the enhanced stability of i-motif structure. Compared to their free states in a dilute solution, the transition pH of all i-motif DNAs decorated in nanochannels remarkably shifts toward a neutral pH. Moreover, the transition midpoint can be tuned sensitively over the physiologically relevant pH range through slightly varying the length of T base spacer. Density functional theory (DFT) calculations validate that the increased proton density in a nanochannel triggers the formation of an i-motif structure under a neutral pH. Finally, this i-motif DNA based nanochannels electrode was successfully employed to monitor pH in brain microdialysates followed by cerebral ischemia. The present approach is not limited by fundamental investigation for DNA conformation but may extend toward the manipulation of i-motif based structures for artificial molecular machines and signaling systems.
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JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Qi Liang,Xiaoying Fu,Jianfeng Zhang,Jiaxue Hao,Gangjun Feng,Jing Wang,Qian Li,Faizan Ahmad,Xinfeng Zhao
The enormous growth in drug discovery paradigm has necessitated continuous exploration of new methods for drug-protein interaction analysis. To enhance the role of these methodologies in designing rational drugs, this work extended an immobilized angiotensin II type I receptor (AT 1 R) based affinity chromatography in antihypertensive compound identification. We fused haloalkane dehalogenase at C-terminus of AT 1 R and expressed the fusion receptor in E. coli. The expressed receptor was covalently immobilized onto 8.0 μm microspheres by mixing the cell lysate with 6-chlorocaproic acid-modified amino polystyrene microspheres. The immobilized AT 1 R was utilized for thermodynamic and kinetic interaction analysis between the receptor and four specific ligands. Following confirmation of these interactions by molecular docking, we identified puerarin and rosmarinic acid by determining their binding to the receptor. Azilsartan, candesartan, valsartan and olmesartan displayed two kinds of binding sites to AT 1 R by injection amount-dependent method. By molecular docking, we recognize the driving forces of the interaction as electrostatic interaction, hydrogen bonds and van der Waals force. The dissociation rate constants (k d ) of azilsartan, candesartan, valsartan and olmesartan to AT 1 R were 0.01138 ± 0.003, 0.05142 ± 0.003, 0.07547 ± 0.004 and 0.01310 ± 0.005 min −1 by peak profiling assay. Comparing with these parameters, puerarin and rosmarinic acid presented lower affinity (K A : 0.12 × 10 4 and 1.5 × 10 4 /M) and slower kinetics (k d : 0.6864 ± 0.03 and 0.3005 ± 0.01 min −1 ) to the receptor. These results, taking together, indicated that the immobilized AT 1 R has the capacity to probe antihypertensive compounds.
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CHEMICAL ENGINEERING SCIENCE
·
2019
·
IF 3.372
Jianjun Wang,Wenheng Li,Zihan Zhou,Zhiyong Gao,Yuehua Hu,Wei Sun
Fluorite is usually separated from calcite by froth flotation method using large amounts of sodium silicate depressant, which can cause trouble in the loss of fluorite and wastewater treatment. In this study, green and low-cost 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP or H 4 L) was used as pH-dependent switch to initially depress fluorite for calcite pre-removal at pH 6.0, and then activate fluorite for further upgrading fluorite concentrate at pH 8.0. The depressing behavior and mechanism were reported in this work. H 2 L 2− was the dominant form of HEDP, and a stronger chemical adsorption of H 2 L 2− on fluorite hindered the subsequent adsorption of sodium oleate (NaOL), while that of the calcite showed the opposite result. Two active O atoms in H 2 L 2− could well match in interatom distance with two Ca sites on fluorite to form Ca-H 2 L complexes. The pH-dependent switch reagent reported here may open a new avenue for more selective separation among mixed mineral systems.
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Journal of Cleaner Production
·
2023
·
IF 11.1
Dongping Song,Tao Huang,Yinglan Luo,Di Wu,Shouze Li,Yujie Yan,Chaojun Yang,Qi Fang,Yuxing Wang,Yuxuan Feng,Nan Shang,Ming Xia,Haiyan Li
Thallium(I) (Tl(I)) is a highly toxic substance with significant environmental toxicity, belonging to the high-toxicity category, with characteristics of chronic accumulation. In this study, cerium(IV) (Ce(IV)) was incorporated into nonthermal plasma (NTP)-irradiated polyvalent manganese (hydro)oxides and synchronously grafted onto nanographene to synthesize a new type of Mn-based adsorbent (NTP-P-Ce-Mn-NGs) with excellent adsorption capacities for Tl(I) contaminants, aiming to overcome the weak adsorption capacity of existing adsorbents for Tl(I) and propose a new approach to enhance their adsorption performance. The factors including the molar ratios of Ce(SO 4 ) 2 to MnCl 2 , the dosage of nanographene, and the irradiation time of NTP all significantly affected the synthesis of NTP-P-Ce-Mn-NGs. Both the participation of NTP and the intercalation of Ce(IV) exerted a potential influence on the adsorption improvement of Mn-based adsorbents towards Tl(l) contaminants. Different chemical valences of Ce and Mn species were observed in the synthesized adsorbent. More flocculated and amorphous fillings were generated in the adsorbent samples with both Mn and Ce, visually presenting the incorporation effect of Ce into the NTP-irradiated Mn (oxy)hydroxides. A maximum adsorption capacity of 352.18 mg/g was obtained by NTP-P-Ce-Mn-NGs at an initial pH of 11, an initial concentration of Tl(I) of 250 mg/L, and a dosage of adsorbent of 0.15 g/L. The kinetics models, including the pseudofirst-order , pseudonth-order , mixed 1,2-order , and hyperbolic tangent Ⅱ models, were all appropriate for analysing the heterogeneous adsorption process of NTP-P-Ce-Mn-NG towards Tl(I) ions under different pH conditions. The excessive OH − ions in the alkaline environment intensified the adsorption of Tl(I) ions onto the active sites of NTP-P-Ce-Mn-NGs and further strengthened the relevant chemical reactions in which the polyvalent Mn and Ce further oxidized Tl species from Tl(I) to Tl(III), induced internal dispersion of Tl ions by the nanographene into the molecular structure and achieved chemical immobilization.
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Biomedicines
·
2023
·Vol. 11
·期 7
·2030
·
IF 4.7
Jie Zhao,Geng Tian,Haibin Qu
The continuous twin-screw wet granulation (TSWG) process was investigated and optimized with prediction-oriented I-optimal designs. The I-optimal designs can not only obtain a precise estimation of the parameters that describe the effect of five input process parameters, including the screw speed, liquid-to-solid (L/S) ratio, TSWG feed rate, and numbers of the 30° and 60° mixing elements, on the granule quality in a TSWG process, but it can also provide a prediction of the response to determine the optimum operating conditions. Based on the constraints of the desired granule properties, a design space for the TSWG was determined, and the ranges of the operating parameters were defined. An acceptable degree of prediction was confirmed through validation experiments, demonstrating the reliability and effectiveness of using the I-optimal design method to study the TSWG process. The I-optimal design method can accelerate the screening and optimization of the TSWG process.Keywords:twin-screw wet granulation (TSWG);I-optimal design;continuous manufacturing;process understanding;design space
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Nanoscale
·
2023
·
IF 6.7
Xin Huang,Haitao Li,Bin Zhang,Yin Zhang,Hao Wang,Lijun Ban,Yixuan Xu,Yongxiang Zhao
It has been widely recognized that adjusting the size of Au particles has emerged as a significant approach in catalyst design, catalyst screening, and comprehension of reaction mechanisms. However, the essential factors of Au nanoparticles used only as an additive to enhance the activity of traditional multicomponent thermocatalysts have not been fully revealed. In this study, a series of Au@Cu2O core–shell nanocatalysts were synthesized through a controllable method, featuring core sizes ranging from 11 to 33 nm and an average shell thickness of approximately 55 nm. It was revealed that the size effect of Au cores plays a very vital role in the stability of the active Cu+ species under reducing atmospheres (H2, acetylene and formaldehyde) as well as the catalytic performance of the catalysts in the ethynylation of formaldehyde. The experimental findings revealed that Au@Cu2O core–shell catalysts with Au core sizes ranging from 11 to 16 nm exhibited a higher abundance of electron-deficient Cu+ species in the shell, which is attributed to the strong long-range electromagnetic effects of the Au core in the absence of photoexcitation or an applied electric field. Additionally, the active Cu+ species demonstrated remarkable stability under reducing atmospheres. Although the stability of Cu+ decreased slightly when the Au core size exceeded 16 nm, the Cu+ content remained above 80%. Notably, the Au@Cu2O catalysts with Au core sizes ranging from 11 to 16 nm exhibited excellent catalytic activity in the ethynylation of formaldehyde.
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FOOD CONTROL
·
2023
·
IF 6
Chenfei Han,Yu Xiao,Zhenjiang Liu,Daolin Du,Ming Li
To improve the performance of aptasensor, the coupling of novel material and strategy had been the hottest research with the promising prospects. In this study, a cascade amplifying aptasensor (CA-aptasensor), which had coupled the DNase I-assisted cyclic enzyme digestion and AgNPs@gel-enhanced fluorescence, had reflected the desired performance for positively correlated detecting OTA . For this purpose, the GO@PVP was used to adsorb and quench the free FAM-Apt, while the complex of OTA and FAM-Apt was digested by the DNase I. The released OTA allowed the free FAM-Apt to separate from the GO@PVP cyclically, thus the OTA level was amplified preliminarily. The AgNPs@gel could combine with the released FAM to form the metal enhanced fluorescence (MEF) effect, resulting in the cascade signal amplification. The OTA was detected at pg mL −1 level with an ultrasensitive LOD of 3.33 pg mL −1 and IC 50 of 13.6 pg mL −1 , which improved 90-fold and 728-fold than that of ELASA for same aptamer. The CA-aptasensor indicated high specificity, reliability and practicability. Meanwhile, the CA-aptasensor exhibited more highlights, including the efficient homogeneous system, low background signal and standardized aptamer recognizer. This study might provide a new approach for improving the performance of aptasensor, which could also guide the signaling cascade and positively correlated detection for other risk factors.
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ACS Applied Nano Materials
·
2023
·
IF 5.9
Lei Zhong,Weisong Li,Guoning Li,Zhaoyu Feng,Chunjian Xu
I-deficient nanoplatelet bismuth oxyiodide (BiOI) microflowers were successfully synthesized via a one-pot solvothermal method using NaOH. Results demonstrated that OH– played a key role in regulating the morphology, pore structure, and energy band structure of the prepared samples. As the volume of NaOH increased, the size of the BiOI microflowers gradually decreased, and the specific surface area and pore volume increased, providing more accessible active sites for photocatalytic reactions. Additionally, some iodine atoms in B-7 (i.e., 7 mL of a 1.0 M NaOH solution was added during the synthesis process) were replaced by hydroxide ions, affording B-7 with slight defects. The loss of iodine atoms shifted the valence band maximum (VBM) from 1.372 eV for the pristine BiOI (B-0) to 1.596 eV for I-deficient BiOI (B-7). The lowered VBM provides more oxidative holes, which is favorable for the oxidation reaction. The photocatalytic activities of the prepared samples were evaluated via the photodegradation of various organic pollutants, such as methyl orange, Rhodamine B, and phenol, under visible light. Owing to the higher surface area and pore volume, lower VBM, and presence of surface defects, B-7 exhibited the highest degradation efficiency among all of the samples.
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FUEL PROCESSING TECHNOLOGY
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2023
·
IF 7.5
Qiang Le,Zan Liu,Zhilin Cheng
In this work, a novel core-shell nanostructured coaxial nanofiber membranes (CFMs) were successfully produced by the coaxial electrospinning . The structure and composition of CFMs were probed by a series of characterizations. The results demonstrated that the CFMs were comprised of the versatile core-shell structure nanofibers, therein Cu(I)/UIO-66 scattered in the shell layer and HNTs dispersed in the core layer. As applied in the selective adsorption desulfurization , the Cu(I)/UIO-66 embedded on the surface of the nanofiber undertook the adsorption active sites, while HNTs in core layer served as enhancing the mechanical performance of PAN nanofibers. The CFMs had the superior adsorption performance in the batch adsorption (maximum:40.14 mg·g −1 ) and fixed-bed adsorption (maximum: 47.43 mg·g −1 ) capacities for benzothiophene (BT) from fuel oil, respectively. Furthermore, due to having the robust mechanical performance, the CFMs exhibited the preferable recycling adsorption and mechanical stability . The adsorption mechanism of BT molecules on CFMs was explored by the kinetics, isotherms and thermodynamic models , indicating the existence of the synergistic effect of physical adsorption and chemical adsorption.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2018
·
IF 3.779
Yanfang Xu,Jinhuan Li,Huanmin Ji,Xuexue Zou,Jiaojiao Zhang,Yi Yan
The dielectric-dielectric composite (SRGA) for electromagnetic absorber was fabricated via integrating Ag(I)-Schiff base coordination compounds (SSBCC) with three-dimensional reduced graphene aerogel (3D-rGA) powders. SRGA showed excellent electromagnetic wave absorption properties in terms of reflection loss, absorption band width and absorber thickness. Specially, when the mass ratio of SSBC to 3D-rGA powders was 1:3 (SRGA-25), the maximum value of reflection loss at 2 mm was up to −63.82 dB and the effective frequency bandwidth of 6.28 GHz (10.16–16.44 GHz) at 2.5 mm can be obtained. The mechanism investigation of electromagnetic wave absorption for SRGA showed that the enhanced electromagnetic wave absorption was ascribed to enhanced polarization loss derived from good 3D-conductive-network units of 3D-rGA, abundant interfaces caused by the media heterostructure due to the introduction of SSBCC and the good impedance matching condition. And 3D-rGA based materials might be put into practical application only in powder state due to the very low strength of the buck state. Therefore, the investigation on SRGA in our contribution is considered to be an actual performance evaluation of the materials based on three-dimensional graphene for microwave attenuation. This work also provided a method for fabricating excellent graphene-based electromagnetic wave absorbers by simply mixing a suitable dielectric lossy material, e.g. SSBCC.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 8
·1-8
·
IF 5.479
Liu Jianbo,Shang Yonghui,Zhu Qiuyan,Zhang Xinxue,Zheng Jianbin
A voltammetric immunoassay for the carcinoembryonic antigen (CEA) was developed using silver metal-organic frameworks (Ag-MOFs) as a signal probe. The Ag-MOFs contained a substantial amount of Ag(I) whose electrochemical signal was relatively stable. Therefore, the Ag-MOFs were viable signal probes. The signal can be detected without previous acid dissolution and preconcentration steps. This simplifies the detection steps and reduces the detection time. If CEA binds to its antibody on the modified electrode, the signal for Ag(I) becomes reduced. Measurements were best performed at a potential as low as 0.07 V (vs. SCE) which made the electrode hardly sensitive to potential electroactive interferents. Under optimized conditions, the method included a wide linear response range (0.05 to 120 ng mL −1 ) and a low detection limit of 8.0 fg mL −1 (S/ N = 3). The synthesis of Ag-MOFs is relatively simple, and Ag-MOFs are not only used as nanocarriers for immobilizing anti-CEA but also acted as electroactive materials for a signal probe. The voltammetric immunoassay is stable, inexpensive, sensitive, and selective. Based on these advantages, the method holds great promise for applications in the point-of-care disease and environmental monitoring.
Schematic presentation of a novel electrochemical immunoassay for the carcinoembryonic antigen (CEA) using silver metal-organic frameworks (Ag-MOFs) as a signal probe.
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JOURNAL OF COORDINATION CHEMISTRY
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2018
·
IF 1.703
Jiajia Lai,Xianying Duan,Hui Yang,Meilin Wei
Two proton-conductive Cu(I) complexes based on Keggin-type clusters, [Cu(debqdc)2]2[HPW12O40]·4H2O (1), and [Cu(debqdc)2]2[HPW12O40]·debqdc·4H2O (2), where debqdc is diethyl 4,4′-dicarboxy-2,2′-biquinoline, were simply synthesized at room temperature. The products were structurally characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction analyses. Single-crystal X-ray diffraction analyses revealed that both complexes crystallized in the triclinic space group P−1 and presented two three-dimensional supramolecular networks with one-dimensional hydrophilic channels via hydrogen-bonding interactions and π–π stacking interactions between the aromatic rings. In the [Cu(debqdc)2]+ ion, debqdc acts as a bidentate nitrogen donor ligand in the chelating fashion. The bulky debqdc ligand constrains the Cu(I) metal center within such a rigid environment in a tetrahedral geometry. The two complexes exhibit good proton conductivities (10−5 ~ 10−4 S cm−1) at 100 °C in the relative humidity range 35 ~ 98%. The luminescence behaviors of these complexes in the solid state at room temperature have also been investigated. Upon excitation at 285 nm, both 1 and 2 display three main emission peaks centered at 470, 520, and 568 nm, respectively.
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