Catalysis Science & Technology
·
2019
·Vol. 10
·期 4
·1056-1065
·
IF 5.726
Xiaoliang Guo,Zhiming Liu,Fang Liu,Jun Zhang,Lekai Zheng,Yongchuan Hu,Jing Mao,Hui Liu,Yanming Xue,Chengchun Tang
The development of efficient, stable and inexpensive electrochemical water-splitting catalysts for the hydrogen evolution reaction (HER) over a wide range of pH is of great importance for the production of hydrogen resource. Defect engineering with electronic structure modulation has been expected to be an effective strategy to enhance the electrocatalytic activity. Herein, Ni–Co bimetallic sulfide (NiCo2S4) nanosheet arrays with controlled sulfur vacancies have been developed by multiple vulcanization treatment of the Ni–Co hydroxide precursor for HER catalysis at all pH values. The presence of S vacancies has been identified by various characterization means, and their effects on the HER performance are well investigated. The obtained NiCo2S4 nanosheet arrays with optimal sulfur vacancy content exhibit the best HER performance in alkaline medium, only requiring an overpotential of 150 mA at −10 mA cm−2 with a Tafel slope of 82.5 mV dec−1, as well as excellent durability. Experimental results confirm that the high HER activity could be ascribed to the accelerated electron transfer and good intrinsic activity for the electrocatalyst with optimal S vacancies. These findings should provide a new vacancy modulation for traditional transition metal chalcogenides for the purpose of boosting the HER performance at all pH values.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Xingyu Liu,Jinwei Gao,Wanqiang Liu,Qianming Wang
Lead halide perovskites have generated remarkable progress in a wide variety of opto-electronic fields. However, challenging issues including water-sensitive feature, poor stability over temperature change and mechanical fragility should be circumvented to enable the practical uses of such nanocrystals . Ethylene-propylene-diene monomer (EPDM) rubber, which possesses saturated and nonpolar polymeric chain, has been extensively explored in industry due to its sealing property, low-cost, dynamic and outstanding abrasive resistance. In this study, the hybrid inorganic-organic network with covalent cross-linkages and CsPbX 3 (X = Cl and Br) quantum dots has been established in EPDM rubber system via an effective and mild approach in the process of mixing reaction at room temperature. In contrast to pure perovskite dots, the peak emission intensity of CsPb(Cl 0·25 Br 0.75 ) 3 -EPDM can be well maintained after it has been immersed into aqueous solution for 2 h. Moreover, the water-mediated treatment will control the emission color evolution from cyan (485 nm) to green (510 nm) and such process can be fully reversible during the soaking and drying cycles. In addition, the employment of such polymeric host with superior heat resistance results in significant increases in thermal stability, mechanical strength and toughness. This efficient strategy will provide a rational design of reinforcing photoluminescence for all-inorganic perovskite quantum dots in numerous applications.
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2019
·
IF 2.687
Penghui Chen,Qiang Liu,Xiaoying Li,Yagang Feng,Xiaopu Chen,Xin Liu,Lexiang Wu,Jiang Li
Y 0.16 Zr 0.84 O 1.92 nanopowders were co-precipitated from the mixed solution of zirconium oxychloride and yttrium nitrate using ammonia as the precipitant. The influences of terminal pH value on the chemical composition and morphology of the Y 0.16 Zr 0.84 O 1.92 precursors and powders were characterized. The precursors with terminal pH = 8.5–9.25 completely transform to cubic ZrO 2 phase when calcined at 800 °C. The Y 0.16 Zr 0.84 O 1.92 powder with terminal pH = 9.0 shows the best dispersity, which is beneficial to the fabrication of transparent ceramics. Using the synthesized nanopowders as starting materials, Y 0.16 Zr 0.84 O 1.92 ceramics were prepared by pre-sintering at 1350 °C for 2 h in air and HIP post-treatment at 1800 °C for 3 h under 200 MPa Ar without sintering additives. The Y 0.16 Zr 0.84 O 1.92 ceramic sample fabricated from the powder with terminal pH = 9.0 shows the best optical quality, and its in-line transmittance exceeds 56.4% in the region of 400–850 nm, reaching 67.8% at 800 nm.
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
·
2019
·
IF 3.973
Hu Lin,Quan Wang,Rui Zhong,Zhen Li,Weifeng Zhao,Yuanwei Chen,Meng Tian,Xianglin Luo
pH-responsive nanocarriers such as polymeric micelles that self-assemble from amphiphilic copolymers containing amino groups have been limited by their significant effects on the blood and thus compromise of their hemocompatibility due to the amino group-induced positive charges. Here we report a biomimetic phosphorylcholine strategy to improve the hemocompatibility of the pH-responsive micelles with positive charges. Amphiphilic copolymers containing different number of tertiary amino groups were synthesized in five steps through ring opening polymerization, azide reaction, thio-bromo “Click” chemistry, and atom transfer radical polymerization to self-assemble biomimetic phosphorylcholine micelles with pH-responsiveness, which shown no significant effects on red blood cells, coagulation, and platelet activation. Moreover, albumin adsorption on the micelles was significantly lower than that of polycaprolactone-methoxypolyethylene glycol (PCL-mPEG) control, and in terms of immune cells, the micelles showed controllable phagocytosis that dependent on the number of tertiary amino groups, in which the one containing four tertiary amino groups in its corresponding copolymer remains had a lower phagocytosis by whole blood leukocyte than that of PCL-mPEG. Based on these results, the hemocompatibility related mechanism of the micelles was discussed and proposed. Our findings demonstrated that this biomimetic phosphorylcholine is a promising strategy to improve the hemocompatibility of the positively charged nanocarriers.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry B
·
2019
·Vol. 8
·期 6
·1223-1234
·
IF 5.047
Huiru Li,Xinyue Zhang,Xilin Lin,Shuqiang Zhuang,Yan Wu,Zhong Liu,Jianhua Rong,Jianhao Zhao
Based on the concept of starving tumor therapy, in this study we put forward a new idea that the pH-sensitive Ca2+ delivery of calcium carbonate nanoparticles (CaCO3 NPs) induced blood coagulation of tumor vessels, and first explored the effect of CaCO3 NPs on the in vitro and in vivo blood coagulation by acid stimulus. CaCO3 NPs with a size of about 100 nm and a porous structure of several nanometers were synthesized in an emulsion system, which showed a high loading capacity (49%) of doxorubicin hydrochloride (DOX) with an encapsulation efficiency of 98% and a pH-sensitive drug delivery. The hemolysis test showed that CaCO3 NPs were blood compatible. The in vitro Ca2+ delivery and blood clotting tests indicated that CaCO3 NPs pH-sensitively released Ca2+, and caused rapid blood coagulation at pH 5.0 but no thrombus at pH 7.4. Confocal laser scanning microscopy showed that after uptake by MCF-7 or MDA-MB-231 breast cancer cells, CaCO3 NPs mainly distributed in endosomes/lysosomes within the initial 2 h and then decomposed by acid stimulus, leading to the intracellular delivery of Ca2+ that subsequently migrated outside the cells. CaCO3 NPs were nontoxic to NIH3T3 mouse fibroblasts, but highly toxic to both MCF-7 and MDA-MB-231 cells after loading DOX. After topical administration into the breast tumors of mice, CaCO3 NPs evoked significant thrombosis and hemorrhage of tumor vasculature by hematoxylin–eosin and Masson's trichrome staining. These results indicated that CaCO3 NPs could induce blood coagulation via acid stimulus, showing potential applications in blocking tumor vessels for starving tumor therapy.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LANGMUIR
·
2019
·
IF 3.683
Hong Chen,Wenxin Fu,Zhibo Li
During the process of emulsifying and hydrolyzing, reactive poly(3-(triethoxysilyl)propyl methacrylate)-b-polystyrene (PTEPM-b-PS) diblock copolymers can self-assemble and become cross-linked to form hollow spheres in situ with polystyrene on their inner surfaces. The addition of tetraethoxysilane (TEOS), which was hydrolyzed and condensed together with PTEPM block, can make those spheres as soft foldable capsules or hard hollow spheres depending on the amount of added TESO. Then postmodification, the surface-initiated Atom Transfer Radical Polymerization (ATRP) was applied to afford stimuli-responsive spheres, and the corresponding responsive Janus nanoplates (RJPs) were finally obtained by crushing those responsive hollow spheres (HSs) showing smart tunable emulsifiability and great potential in oily water purification. This facile method to fabricate HSs and RJPs could be used for preparing different Janus polymer-inorganic capsules and nanoplates with varied functions by changing the chemical composition of copolymer surfactants as well as the postmodification process.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Zhaolan Zhai,Ji Xu,Xinyan Yan,Zhanqian Song,Shibin Shang,Xiaoping Rao
pH-responsive aqueous foams were prepared by using a totally rigid surfactant, sodium N -azobenzenemaleimidepimaric carboxylate (Na-MPA-AZO-Na), derived from rosin. When the pH of aqueous solution decreases from 12.35 to 9.31, a Bola surfactant converts into a traditional surfactant containing a hydrophilic group and a hydrophobic group (Na-MPA-AZO), which severely affects the foaming ability and foam stability. And such changes of molecular configuration were rare reported. When the pH of aqueous solution is 9.31, the Na-MPA-AZO molecule tends to be upright at the air/water interface, which results in a close surfactant arrangement. The original volume of foams at 2 mM is 72 mL, and its half-life is up to 2145 min, which are far larger than that of sodium dodecyl sulfate (SDS) at the same concentration as a reference. When the pH of aqueous solution is 12.35, the Bola surfactant Na-MPA-AZO-Na tends to lie at the air/water interface in a V configuration, which leads Na-MPA-AZO-Na easily to desorb from the interface. The original volume of foams at 2 mM is only 9.5 mL, and its half-life is only 2 min, the foams will completely disappear in 6 min. The stable and unstable foams can be reversed at least 3 times by alternating the pH between 9.31 and 12.35. Besides, because of the fixed positions of carbon atoms in the totally rigid skeleton, the pH-responsive foams show highly pH-responsive efficiency.
✓ 已验证
产品关联
DOI
高影响因子
Nano Research
·
2019
·Vol. 12
·期 11
·2815-2826
·
IF 8.515
Zhang Xiaolei,Zhang Chuangnian,Cheng Mingbo,Zhang Yahui,Wang Wei,Yuan Zhi
The strategy of pH-responsive aggregation in tumor micro-environment (TME) provides an intriguing platform for enhancing tumor retention and exerting therapeutic effects sufficiently. In this work, we have designed an intelligent dual pH-responsive self-aggregating nano gold system (Au@PAH-Pt/DMMA) for the combined chemo-radiotherapy, in which a “charge-reversal like” strategy was utilized to realize irreversible stable aggregation and pH-specific release of cisplatin prodrug in TME. Responsive aggregation increases the cellular uptake of Au@PAH-Pt/DMMA by 55%–60%, and the cellular uptake of Pt after X-ray irradiation can be further enhanced by 80%. Additionally, responsive aggregation greatly slows down the rate of efflux from tumor in vivo . This system not only promotes B16 cell apoptosis as a chemotherapeutic agent (30.4%), it also enhances the effect of chemo-radiotheray (CRT) by promoting apoptosis as a radiosensitizer (55.3%). The colony formation assay results were fitted to cell survival curve of B16 cells and the sensitization enhancement ratio (SER) was calculated to be 1.29, which shows a good radiosensitizing ability. When exposed to X-ray, this nanoplatform reached the ideal therapeutic effect, and the tumor inhibition rate of Au@PAH-Pt/DMMA reached 91.6% with low drug administration frequency and dose of X-ray. Overall, the dual pH-responsive nanoparticles Au@PAH-Pt/DMMA could effectively enhance tumor therapeutic efficiency by combined chemo-radiotherapy, which provides a potential method for clinical transformation of cancer treatment.
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 10
·1564
·
IF 3.164
Tong Wang,Xuan Zhang,Zichao Wang,Xiuzhong Zhu,Jie Liu,Xin Min,Tao Cao,Xiaodong Fan
Stimuli-responsive conductive hydrogels have a wide range of applications due to their intelligent sensing of external environmental changes, which are important for smart switches, soft robotics, and flexible sensors. However, designing stimuli-responsive conductive hydrogels with logical operation, such as smart switches, remains a challenge. In this study, we synthesized pH-responsive conductive hydrogels, based on the copolymer network of acrylic acid and hydroxyethyl acrylate doped with graphene oxide. Using the good flexibility and conductivity of these hydrogels, we prepared a flexible sensor that can realize the intelligent analysis of human body motion signals. Moreover, the pH-responsive conductive hydrogels were integrated with temperature-responsive conductive hydrogels to develop logic gates with sensing, analysis, and driving functions, which realized the intellectualization of conductive hydrogels.Keywords:stimuli-responsive conductive hydrogels;pH-responsive;composite hydrogels;flexible sensors;logic gates
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Xuqian Zhang,Ying He,Zitong Yuan,Guangmao Shen,Zan Zhang,Jinzhi Niu,Lin He,Jinjun Wang,Kun Qian
Thiacloprid is a new chlorinated nicotinoid insecticide against stinging-oral pests, such as aphids. It is less toxic to bees but more toxic to earthworms. In this study, a pH- and amylase-responsive MOF (ZIF-8) was constructed for site-specific delivery of thiacloprid to control pea aphids and more safety for earthworms. Thiacloprid from α-cyclodextrin@Thiacloprid@ZIF-8 (α-CD@T@ZIF-8) could be released quickly in pea aphids, which was ascribed to disintegration of ZIF-8 at low pH values in pea aphid intestines and degradation of α-CD under the action of α-amylase. The release results showed a significant pH dependence of α-CD@T@ZIF-8, with an approximately 65 % release amount at pH = 7 and a 95 % release amount at pH = 5 for 7 d. The results of the pot experiment and biosafety showed that for α-CD@T@ZIF-8, 88 % pea aphids could be killed compared with 32 % aphids for commercially available formulation on the 7th day after application. Meanwhile the LC 50 of thiacloprid OD was 0.034 μg/cm 2 and the LC 50 of α-CD@T@ZIF-8 was 0.564 μg/cm 2 on earthworms, and it was more safety for pea and lower acute toxicity and enrichment for the earthworms. α-CD@T@ZIF-8 could be used for intelligently controlled release of other insecticides against aphids.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD HYDROCOLLOIDS
·
2022
·
IF 11.504
Ya-Ru Wang,Qin Yang,Ya-Nan Du,Han-Qing Chen
Food protein fibrils display superior mechanical and interfacial properties compared to the native protein. During processing, protein fibrils are stored for a long time and undergo pH shifts, which accelerate their degradation. In this study, the effects of chitosan on the morphology, structural and rheological properties of ovalbumin (OVA) fibrils after storage at pH higher than isoelectric point were studied. The results showed that OVA fibrils prepared at pH 2.0 remained stable after 7 days of storage. However, after storage at pH 8.0 for 7 days, the turbidity of OVA fibrils increased, the contour length and ThT fluorescence intensity decreased. Furthermore, OVA fibrils became stable again by interacting with chitosan via electrostatic interaction, which was confirmed by zeta potential . In addition, based on the results of Fourier transform infrared spectroscopy , sodium dodecyl sulfide polyacrylamide gel electrophoresis , and fluorescence spectra, it could be concluded that chitosan could interact with OVA fibrils at pH 8.0 during storage. Transmission electron microscope images indicated that the structure of OVA fibrils was maintained by the addition of positively charged chitosan. Finally, the viscosity and storage modulus of OVA fibrils after storage at pH 8.0 increased with the addition of chitosan. These findings implied that OVA fibrils were degraded when stored at pH above isoelectric point, but this degradation could be ameliorated by the addition of chitosan.
✓ 已验证
产品关联
DOI
高影响因子
Acta Biomaterialia
·
2022
·
IF 10.633
Linzhu Su,Yuanfeng Li,Shuang Tian,Fan Huang,Yijin Ren,Cuihong Yang,Henny C. van der Mei,Henk J. Busscher,Linqi Shi
Antibiotic-loaded PEG/PAE-based micelles are frequently considered for eradicating infectious biofilms. At physiological pH, PEG facilitates transport through blood. Near an acidic infection-site, PAE becomes protonated causing micellar targeting to a biofilm. However, micellar penetration and accumulation is confined to the surface region of a biofilm. Especially matured biofilms also possess hypoxic regions. We here designed dual-responsive PEG/PAE- b -P(Lys-NBCF) micelles, responding to both acidity and low oxygen-saturation level in matured biofilms. Dual, pH- and hypoxia-responsive micelles targeted and accumulated evenly over the depth of 7- to 14-days old biofilms. Delineation demonstrated that pH-responsiveness was responsible for targeting of the infection-site and accumulation of micelles in the surface region of the biofilm. Hypoxia-responsiveness caused deep penetration in the biofilm. Dual, pH- and hypoxia-responsive micelles loaded with ciprofloxacin yielded more effective, synergistic eradication of 10-days old, matured Staphylococcus aureus biofilms underneath an abdominal imaging-window in living mice than achieved by ciprofloxacin in solution or single, pH- or hypoxia responsive micelles loaded with ciprofloxacin. Also, wound-healing after removal of window and its frame proceeded fastest after tail-vein injection of ciprofloxacin-loaded, dual, pH- and hypoxia-responsive micelles. Concluding, pH- and hypoxia-responsiveness are both required for eradicating mature biofilms and advancing responsive antibiotic nanocarriers to clinical application. Statement of significance pH-responsive antibiotic nanocarriers have emerged as a possible new strategy to prevent antimicrobial-resistant bacterial infections from becoming the leading cause of death. In this paper, we show that commonly studied, pH-responsive micellar nanocarriers merely allow self-targeting to an infectious biofilm, but do not penetrate deeply into the biofilm. The dual-responsive (acidic pH- and hypoxia) antibiotic-loaded micelles designed here not only self-target to an infectious biofilm, but also penetrate deeply. The in vitro and in vivo advantages of dual-responsive nanocarriers are most obvious when studied in infectious biofilms grown for 10 viz a viz the 2 days, usually applied in the literature. Significantly, clinical treatment of bacterial infection usually starts more than 2 days after appearance of the first symptoms.
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）