Nature Communications
·
2021
·Vol. 12
·期 1
·1-10
·
IF 14.919
Zhang Lufeng,Zhang Liang,Deng Hui,Li Huan,Tang Wentao,Guan Luyao,Qiu Ye,Donovan Michael J.,Chen Zhuo,Tan Weihong
Helicobacter pylori infection is a major etiological factor in gastric diseases. However, clinical antibiotic therapy for H. pylori is limited by continuously decreased therapeutic efficacy and side effects to symbiotic bacteria. Herein, we develop an in vivo activatable pH-responsive graphitic nanozyme, PtCo@Graphene (PtCo@G), for selective treatment of H. pylori . Such nanozymes can resist gastric acid corrosion, exhibit oxidase-like activity to stably generate reactive oxygen species only in acidic gastric milieu and demonstrate superior selective bactericidal property. C 18 -PEG n -Benzeneboronic acid molecules are modified on PtCo@G, improving its targeting capability. Under acidic gastric pH, graphitic nanozymes show notable bactericidal activity toward H. pylori , while no bacterial killing is observed under intestinal conditions. In mouse model, high antibacterial capability toward H. pylori and negligible side effects toward normal tissues and symbiotic bacteria are achieved. Graphitic nanozyme displays the desired enzyme-like activities at corresponding physiological sites and may address critical issues in clinical treatment of H. pylori infections.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2021
·
IF 6.986
Juan Qiao,Yuying Song,Chuanfang Chen,Li Qi
Sialic acid (SA) is an important monosaccharide that is involved in incurable cancer immunotherapy. However, it is difficult to detect SA in situ using the existing strategy based on the SA-terminated glycopeptide extraction from the cell lysate. The countermeasures of the bottleneck caused by cell disruption and peptide extraction should be designed based on a “cell-surface attachment and controlled enzymolysis” protocol. Herein, a poly(styrene-co-maleic anhydride-acrylic acid-concanavalin A) (PSM-PAA-ConA) was synthesized and developed as a pH-regulated enzyme nanoreactor after being loaded with sialidase and myoglobin. The nanoreactor showed controllable biocatalysis induced by a cascade enzyme reaction and applied for the in situ detection of SA on a living cell surface. The addition of an acidic solution resulted in a decrease in the size of the nanoreactor and enhancement of its permeability, triggering an “on” state of the SA catalysis. Subsequent pH increase led to increased hydrophilicity of the nanoreactor, increasing its size and resulting in the catalytic “off” state. ConA assisted the cell-surface attachment of the enzyme reactor. Furthermore, SA on the surface of living cancer cells was successfully monitored by the pH-regulated enzyme nanoreactor, demonstrating the feasibility of high specificity in situ analysis for SA. This pH-induced catalytic efficiency control by the enzyme nanoreactor provides a potential platform for functional stimuli-responsive catalytic systems as well as a strategy for in situ analysis of biomolecules on the cell surface.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Fuwei Sun,Tianhu Chen,Haibo Liu,Xuehua Zou,Peixun Zhai,Ziyang Chu,Daobing Shu,Hanlin Wang,Dong Chen
Occurring naturally siderite (FeCO 3 ) was used as the heterogeneous catalyst to activate peroxodisulfate (PDS) for the degradation of sulfadiazine under different initial pH values. The findings of this system exhibited various ROS (e.g. 1 O 2 , SO 4 − and OH) present during a wide range of pH values. Among them, 1 O 2 could significantly facilitate the initial degradation rate, and the increased pH enhanced the role of 1 O 2 . The factors including initial pH values, siderite dosage, PDS concentration, initial contaminants concentration, and water matrix were discussed. The role of each ROS was investigated through quenching test and electron paramagnetic resonance (EPR). Furthermore, the comprehensive degradation process was proposed based on the LC-MS results. And the cycle test demonstrates the reusability of siderite at a pH of 3. Accordingly, this study is of great significance for understanding the degradation of such sulfonamide pollutants in the siderite/PDS system.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2021
·
IF 4.098
Qin Wang,Li-Bing Lü,Zhu Tao,Tao Sun,Qing Tang,Ying Huang
In the present work, we have investigated the effect of pH and mercury ions on the host–guest complex formed between cucurbit[7]uril (Q[7]) and Hoechst 33342 (H33342). 1 H NMR, UV–vis and fluorescence spectroscopy revealed that acid/base stimulation could change the binding stoichiometry between Q[7] and H33342. The results suggest that two complexation equilibria (1:1 and 2:1) may exist between H33342 and Q[7] at pH 2.0 and 4.5, respectively. However, a 1:1 host–guest complex was formed between H33342 and Q[7] at pH 7.0 and 10.0. Q[7] shows differential affinities for the protonated and neutral forms of H33342 dye. Moreover, the switching between H33342∙2H + @2Q[7](1:2) at pH 4.5 and H33342∙H + @Q[7](1:1) at pH 7.0 was reversible. Furthermore, as a metal stimulus, Hg 2+ ions could push (i) Q[7] from the piperazine ring to the benzimidazole position with a 1:1 guest–host ratio and (ii) a second Q[7] onto the ethyl position with a 1:2 guest–host stoichiometry. This stimulus response system will have potential applications in the field of molecular switch design.
✓ 已验证
DOI
PubMed
高影响因子
Pharmaceutics
·
2021
·Vol. 13
·期 3
·338
·
IF 6.321
Ahmed M. Omer,Maha S. Ahmed,Gehan M. El-Subruiti,Randa E. Khalifa,Abdelazeem S. Eltaweil
To develop an effective pH-sensitive drug carrier, alginate (Alg), carboxymethyl chitosan (CMCs), and aminated chitosan (AmCs) derivatives were employed in this study. A simple ionic gelation technique was employed to formulate Alg-CMCs@AmCs dual polyelectrolyte complexes (PECs) microcapsules as a pH-sensitive carrier for efficient encapsulation and release of diclofenac sodium (DS) drug. The developed microcapsules were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyzer (TGA), and scanning electron microscope (SEM). The results clarified that formation of dual PECs significantly protected Alg microcapsules from rapid disintegration at colon conditions (pH 7.4), and greatly reduced their porosity. In addition, the dual PECs microcapsules can effectively encapsulate 95.4% of DS-drug compared to 86.3 and 68.6% for Alg and Alg-CMCs microcapsules, respectively. Higher DS-release values were achieved in simulated colonic fluid [SCF; pH 7.4] compared to those obtained in simulated gastric fluid [SGF; pH 1.2]. Moreover, the drug burst release was prevented and a sustained DS-release was achieved as the AmCs concentration increased. The results confirmed also that the developed microcapsules were biodegradable in the presence of the lysozyme enzyme. These findings emphasize that the formulated pH-sensitive microcapsules could be applied for the delivery of diclofenac sodium.Keywords:alginate;carboxymethyl chitosan;aminated chitosan;pH-sensitive microcapsules;polyelectrolyte complex;drug release
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Nano
·
2021
·
IF 15.881
Jinglin Shen,Qianwen Xiao,Panpan Sun,Jin Feng,Xia Xin,You Yu,Wei Qi
The self-assembly of chiral metal nanoclusters into supramolecular chiral aggregates is of interest for developing advanced materials. Herein, we manipulated the self-assembly of Au nanoclusters modified by l-/d-cysteine (l-/d-AuNCs) into ordered microstructures featuring enhanced phosphorescence and optical activities. The formation of these aggregates was driven by synergistic effect of coordination and electrostatic interactions assisted by Cd2+/H+. Detailed structural characterization and theoretical studies confirmed that the compact aggregation structures are essential for the emission enhancement and the chirality amplification of l-/d-AuNCs. Interestingly, upon the formation of microflowers, the emission lifetime was prolonged to 3.34 ms with a switch from fluorescence to phosphorescence induced by aurophilic Au(I)···Au(I) interactions and intensive ligand-to-metal charge transfer (LMCT). Moreover, both the CD and photoluminescence (PL) signals of the microflowers exhibited pH-responsiveness. This dual-mode sensitive platform could be developed as a pH sensor with improved accuracy. Additionally, the pH-responsive photoluminescence ON/OFF switch of the microflowers could be employed for reliable information encryption and decryption. This study provides useful ideas for regulating the self-assembly of nanoclusters to generate desired photophysical properties with potential applications.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 31
·10838-10844
·
IF 4.39
Xia Xu,Meirong Fu,Penghui Li,Min Yang
While photothermal therapy is widely applied in phototherapy, there are still challenges in developing new generation phototherapy materials with precise diagnostic functions. Here we report the construction of a pH responsive upconversion fluorescence imaging precisely guided photothermal therapy system, namely NaYF4:Yb3+/Er3+@NaYF4@MnO2@Au nanocomposites, which can effectively avoid light damage to non-target tissues. Owing to the fluorescence resonance energy transfer between the upconversion nanocrystal donor and MnO2 and Au acceptor, the upconversion fluorescence is completely quenched. However, in pH 5.3 PBS buffer, MnO2 is gradually broken down, and the upconversion fluorescence is partially recovered, which could be used for upconversion fluorescence imaging to precisely guide photothermal therapy under 980 nm excitation. Simultaneously, due to the absorption of 980 nm excitation light and the emission bands of Er3+ (2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transition), temperature increment of core@shell@MnO2@Au could reach 35.5 °C under 980 nm excitation at 0.8 W cm−2. The core@shell@MnO2@Au nanocomposites are supposed to contribute significantly in the biological applications of photoluminescence imaging and photothermal therapy.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Shiqiang Wang,Yali Cao,Wei Jia,Zhenjiang Lu,Dianzeng Jia
Electrochemical water splitting has been highly considered as a promising technology to produce hydrogen with high purity and large quantity. Herein, a cage-confinement strategy is proposed to encapsulate H 3 PMo 12 O 40 clusters into cavities of ZIF-67. The ZIF-67 with cavity diameter of 1.16 nm and cavity window of 0.34 nm can appropriately confine H 3 PMo 12 O 40 with diameter of 1.0 nm. The H 3 PMo 12 O 40 served as guest species were also homogeneously encapsulated in well-defined cavities of ZIF-67 host without destroying the structure of ZIF-67. This cage-confinement strategy endow Mo 6 Co 6 C nanoparticles uniformly embedded in carbon matrix without aggregation and exposed abundant active sites during pyrolysis process. Furthermore, the heterojunction of Pt-Mo 6 Co 6 C was fabricated through galvanic replacement with H 2 PtCl 6 . The prepared Pt-PMo/ZIF-67-800 electrocatalyst with a low Pt amount of 3.0 % exhibits excellent HER activity and stability and even superior to commercial Pt/C in PH-universal solutions. Density functional theory (DFT) calculation reveals that Pt-Mo 6 Co 6 C heterostructure results in a lower hydrogen adsorption free energy than commercial Pt/C and thus enhances its intrinsic catalytic activity. The outstanding HER performance of Pt-Mo 6 Co 6 C heterostructure confined on dodecahedron carbon matrix opens new perspectives for rational design polyoxometalate (POM) based catalyst for hydrogen evolution.
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2021
·
IF 8.071
Huan-Qin Li,Ying-Jia Shen,Wen-Lei Wang,Hong-Tao Wang,Hu Li,Jian-Qiang Su
Microplastic (MP) pollution is widespread in various ecosystems and is colonized by microbes that form biofilms with compositions and functions. However, compared with aquatic environments, the soil environment has been poorly studied in terms of the taxonomic composition of microbial communities and the factors influencing the community structure of microbes in the plastisphere. In the present study, a microcosm experiment was conducted to investigate the plastisphere bacterial communities of MP (polyvinyl chloride, PVC) in soils with different pH (4.62, 6.5, and 7.46) and arsenic (As) contents (13 and 74 mg kg −1 ). Bacterial communities in the plastisphere were dominated by Proteobacteria and Firmicutes, with distinct compositions and structures compared with soil bacterial communities. Soil pH and As content significantly affected the plastisphere bacterial communities. Constrained analysis of principal coordinates and a structural equation model demonstrated that soil pH had a stronger influence on the dissimilarity and diversity of bacterial communities than did soil As content. Soil pH affected As speciation in soil and on MP. The concentration of dimethylarsinic acid (DMA) was significantly higher on MP than that in soil, indicating that As methylation occurred on MP. These results suggest that environmental fluctuations govern plastisphere bacterial communities with cascading effects on biogeochemical cycling of As in the soil ecosystems.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2021
·
IF 11.236
Lifa Ge,Yamei Yue,Wei Wang,Fatang Tan,Shenghua Zhang,Xinyun Wang,Xueliang Qiao,Po Keung Wong
Currently existing Fenton-like catalysts were limited in wastewater treatment owing to their potential transition-metal poisoning, narrow applicable pH range and high dependence on external energy excitation. In this work, the MgNCN/MgO nanocomposites were firstly synthesized by a facile one-pot calcination of melamine and basic magnesium carbonate, and used as novel H 2 O 2 activator for antibiotic removal. It was found that the MgNCN/MgO composite calcined at 550°C with the mass ratio of melamine to basic magnesium carbonate at 2:1, exhibited an excellent catalytic ability to tetracycline (TC) degradation in a wide pH range of 4-10 without any external energy input. More than 90% of TC (100 mL, 50 mg/L) could be degraded within 30 min by 10 mg of the nanocomposite in the presence of 0.2 mL of 30 wt% H 2 O 2 . Based on the experimental results, it was concluded that the Mg-N coordination between MgNCN and MgO in MgNCN/MgO nanocomposites activated H 2 O 2 to produce primary singlet oxygen ( 1 O 2 ) and minor hydroxyl radicals (·OH), responding for TC degradation. In addition, the degradation pathways of TC were deduced by determining the generated intermediates during the degradation process. This work provided a novel idea for designing transition-metal-free catalysts for nonradical activation of H 2 O 2 in the absence of external energy excitation.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Magnesium and Alloys
·
2020
·
IF 7.115
Yuejun Ouyang,Lin-Xin Li,Zhi-Hui Xie,Lili Tang,Fuhui Wang,Chuan-Jian Zhong
The preparation of pH-responsive nanocontainers by typical silane modification of the mesoporous silica nanoparticle (MSN) surface is usually high-cost, complex, and time-consuming, which remains a great challenge for effective corrosion protection of magnesium alloy. Here, a new strategy to construct pH-responsive nanocontainers (MSN-MBT@LDH) is demonstrated. The nanocontainers consist of corrosion inhibitor (2-mercaptobenzothiazole, MBT) loaded MSN core and layered double hydroxide (LDH) nanosheet shell serving as gatekeepers. The successful loading of MBT and encapsulation by LDH nanosheets were confirmed by a series of characterization such as scanning transmission electron microscopy coupled with energy dispersive X-ray spectroscopy (STEM-EDS) and N 2 adsorption/desorption isotherms. The pH-responsive feature of the nanocontainers was demonstrated by determination of the MBT concentration in buffer solutions with different pH values. A smart corrosion protection system on Mg alloy is obtained by incorporating the synthesized nanocontainers into a self-assembled nanophase particle (SNAP) coating. The electrochemical tests and visual observations show that the hybrid coating has the best barrier properties and robustness in corrosion protection in NaCl corrosive solutions in comparison with the control coatings. The present method simplifies the synthesis processes of nanocontainers and eliminates the potential detrimental effect of excess gatekeepers on the coating. The findings provide new insights into the preparation of scalable nanocontainers. The self-healing coatings are expected to have widespread applications for corrosion protection of Mg alloy and other metals.
✓ 已验证
DOI
高影响因子
Nano Energy
·
2020
·
IF 16.602
Yaguang Li,Yi Wang,Jianmin Lu,Bing Yang,Xingyuan San,Zhong-Shuai Wu
Exploring highly active and stable oxygen evolving electrocatalysts is the key for electrochemical water splitting and renewable chemical conversion. RuO 2 is one of the benchmark oxygen evolving electrocatalysts, but remains challenging in high activity in all-pH electrolytes. Herein, we report a confined oxygenation strategy using the finite oxygen species from graphene oxide to synthesize two dimensional (2D) heterostructures of intrinsically defective RuO 2 nanocrystals uniformly grown on graphene (2D D-RuO 2 /G), showing ultrathin thickness of 9 nm, high specific surface area of 125 m 2 g −1 , enriched hydroxylated surface and notably intrinsic defective RuO 2 with low Ru–O coordination number of 5. Consequently, 2D D-RuO 2 /G exhibits a robust stability and an extraordinary oxygen evolution reaction (OER) performance both in acidic and alkaline solutions, achieving a current density of 10 mA cm −2 at the overpotential of 169 and 175 mV, and a water oxidation turn over frequency of 1.07 and 1.25 S −1 at 270 mV, respectively, corresponding to 344 mV of total overpotential at 10 mA cm −2 in acidic and alkaline electrolytes , which greatly exceeds the state-of-the-art of pH-universal OER electrocatalysts. Theoretical studies indicate that intrinsic defective Ru sites can enhance the adsorption and accelerate the decomposition of hydroxyl groups to boost the OER activity. This confined oxygenation strategy provides the opportunities to construct 2D advanced defective OER electrocatalysts in all-pH electrolytes.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）