CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Wei Jin,Hengbo Wu,Weiquan Cai,Baohua Jia,Munkhbayar Batmunkh,Zexing Wu,Tianyi Ma
Designing highly-efficient and pH-universal electrocatalysts for overall water-splitting reactions is important for the sustainable production of hydrogen. Herein, NiRu nanoparticles encapsulated into N-doped carbon (NiRu@NC) are fabricated with the assistance of MOF for hydrogen evolution reaction (HER) and also evolved into core–shell structured nanomaterials with abundant interfaces for oxygen evolution reaction (OER, Ni/RuOx@C). Benefiting from optimized electronic structure, interfacial synergy effect and special core–shell structure (~150 nm), the newly developed electrocatalysts present remarkable electrocatalytic activities with small overpotentials to drive 10 mA cm −2 for the HER (19 mV in alkaline, 80 mV in neutral, 20 mV in acid) and OER (252 mV, 316 mV, 211 mV). Moreover, the obtained electrocatalysts exhibit outstanding catalytic performances for overall water-splitting in a two-electrode system with 1.53 V and 1.67 V to drive 10 mA cm −2 in basic and neutral electrolyte, respectively. Remarkably, a small potential of 1.47 V is required to deliver 10 mA cm −2 in acidic media and no significant decay of the activity is observed. This work paves the way for designing a novel class of electrocatalyst that can not only exhibit remarkable electrocatalytic water splitting performances in various conditions, but also possess excellent stabilities for future generation of clean energy.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
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IF 4.539
Weiwei Sui,Huawen Hu,Yinlei Lin,Peng Yi,Lei Miao,Haichen Zhang,Haiying He,Guangji Li
Stimuli-responsive materials with switchable wettability for bidirectional oil-water separation show great potential in practical applications. Inspired by mussels, we use dopamine as an anchor molecule to construct a polydopamine (PDA) coating on the surface of copper foam (CF). Silver particles are deposited on the PDA coated surface to construct a multiscale composite structure, and the long-chain alkylthiol with carboxyl and methyl groups at the end is subsequently self-assembled to the modified copper foam surface. The as-modified copper foam has unique pH responsiveness, that is, the water contact angle (WCA) is measured to be about 140° under acidic and neutral conditions, while alkaline conditions radically change the surface property from superhydrophobic to superhydrophilic due to the measured WCA turning to 0°. It can be used efficiently for the bidirectional separation of an oil-water mixture, e.g., the separation efficiency of a 1,2-dichloroethane/water mixture can reach as high as 98.2%. Besides, it maintains 98% separation efficiency and stable wettability for an octane/water mixture, together with excellent mechanical durability; the WCA of the surface maintains at about 130° after ten wear cycles.
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CHEMOSPHERE
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2021
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IF 7.086
Yaohong Ma,Leilei Xiao,Yunwei Wei,P. Senthil Kumar,Yang Tan,Yiwei Li,Hengchang Zang
Microbial fuel cells (MFCs) are sensitive to acidity variations in both bioelectricity generation and biochemical digestion aspects, therefore online pH monitoring is of necessity to guarantee optimal function of MFCs. Present pH meters hardly fulfill this special need. In this work, we designed a novel voltammetric pH sensor based on electrochemically reduced graphene oxide (rGO) modified screen printed electrode. By surface doping of alizarin, good linearity of pH sensing over the range of 4.0–9.0 can be realized. Fast readout can be acquired within 15 s for each test. pH monitoring for artificial wastewater with inoculum of granular activated sludge in a MFC was successfully illustrated. Specially, it was verified that the performance was improved with alizarin doping due to the enhanced rGO surface proton diffusion. This approach provides an online, calibration-free and long stable pH monitoring method for the future MFC development.
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Pharmaceutics
·
2021
·Vol. 13
·期 9
·1464
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IF 6.321
Yang Yang,Fuwei Yang,Xiaotian Shan,Jiamin Xu,Wenjie Fang,Juan Zhou,Lipeng Qiu,Jinghua Chen
At present, the drug is still difficult to release completely and quickly only with single stimulation. In order to promote the rapid release of polymeric micelles at tumor site, pH/reduction sensitive polymers (PCT) containing disulfide bonds and orthoester groups were synthesized. The PCT polymers can self-assemble in water and entrap doxorubicin to form drug-loaded micelles (DOX/PCT). In an in vitro drug release experiment, the cumulative release of DOX/PCT micelles in the simulated tumor microenvironment (pH 5.0 with GSH) reached (89.7 ± 11.7)% at 72 h, while it was only (16.7 ± 6.1)% in the normal physiological environment (pH 7.4 without GSH). In addition, pH sensitive DOX loaded micellar system (DOX/PAT) was prepared as a control. Furthermore, compared with DOX/PAT micelles, DOX/PCT micelles showed the stronger cytotoxicity against tumor cells to achieve an effective antitumor effect. After being internalized by clathrin/caveolin-mediated endocytosis and macropinocytosis, DOX/PCT micelles were depolymerized in intercellular acidic and a reductive environment to release DOX rapidly to kill tumor cells. Additionally, DOX/PCT micelles had a better inhibitory effect on tumor growth than DOX/PAT micelles in in vivo antitumor activity studies. Therefore, pH/reduction dual sensitive PCT polymers have great potential to be used as repaid release nanocarriers for intercellular delivery of antitumor drugs.Keywords:polymeric micelles;doxorubicin;pH/reduction sensitive release;antitumor effect
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高影响因子
SENSORS
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2019
·Vol. 19
·期 17
·3801
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IF 3.031
Tingyu Wang,Guoqing Chen,Lei Li,Yamin Wu
In this report, high-brightness green carbon dots were successfully prepared using 3,5-diaminobenzoic acid as the sole precursor and synthesized in one step using a solvothermal strategy. Under the excitation of 365 nm ultraviolet light, the quantum yield of carbon dots is as high as 53.8%. Experiments revealed that the carbon dots are highly carbonized and the surface is rich in amino and carboxyl groups. The synthesized carbon dots have good water solubility, and are resistant to ions and temperature. The fluorescence intensity of CDs is sensitive to pH changes and is linearly correlated with the pH in the near-neutral range (pH = 6.0 to 9.0). Our experiments showed that carbon dots were sensitive and accurate fluorescent probes for measuring the pH value of drinking water, which could provide an effective method for measuring the pH value of water in the future.Keywords:carbon dots;solvothermal;3,5-diaminobenzoic acid;pH;fluorescent probe
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EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS
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2019
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IF 4.708
Siyu Guan,Qianqian Zhang,Jianwei Bao,Tijie Duan,Rongfeng Hu,Tori Czech,Jihui Tang
In recent decades, targeted drug delivery systems (TDDS) have been widely used as an ideal method of improving therapeutic effects and reducing systemic side effects of chemotherapeutic agents. Historically, a handful of methods have been developed to further improve the targeting ability of delivery systems. Thus, in this study, two methods, taking advantage of tumor characteristics, were used for the creation of a multi-targeted delivery system. The first was the fabrication of pH-sensitive micelles , lending the ability to increase drug release by exploiting the acidic tumor environment. The second method was through utilization of the surface-exposed phosphatidylserine (PS) of tumors, which is normally found in the inner leaflet in healthy cells. Using PS as a target site, PS binding peptide (PSBP-6) was conjugated to pH-sensitive mixed micelles, (consisting of poly (ethylene glycol)-b-poly (D, L-lactide) (PEG-PDLLA) and poly (ethylene glycol)-b-poly (L-histidine) (PEG-PHIS)). After successful preparation of micelles, paclitaxel (PTX), a common chemotherapeutic agent, was selected to measure drug loading capacity and encapsulation efficiency, showing 7.9% and 83.5%, respectively. The in vitro release of PTX from mixed micelles at pH 5.0, 6.5, and 7.4 was 78.1, 56.8, and 51.4%, respectively, indicating acid-triggered drug release. The PSBP-6-modified, mixed micelles exhibited significantly enhanced in vitro cytotoxicity and demonstrated more efficient cellular uptake compared to unmodified mixed micelles in the HeLa cell line. Moreover, pharmacokinetic , in vivo biodistribution , and fluorescence imaging studies showed that PSBP-6-PEG-PDLLA/PEG-PHIS mixed micelles provide prolonged time in blood circulation and enhanced tumor accumulation. These results suggest that the use of PS as a novel targeting site is advantageous, and that these new multi-targeted mixed micelles show great potential for realization of broad prospects in the targeted treatment of tumors for chemotherapeutic delivery.
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Materials Science & Engineering C-Materials for Biological Applications
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2019
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IF 4.959
Xiangping Hao,Shougang Chen,Dong Qin,Mutian Zhang,Wen Li,Jincheng Fan,Chao Wang,Mengyao Dong,Jiaoxia Zhang,Frank Cheng,Zhanhu Guo
Antifouling biocides releasing restricts the longevity of antifouling coatings. Compared with the anchoring state, the releasing behavior of agents is much faster on the voyage, while the biofouling process is tougher. In this work, a series of capsaicin-based pH-triggered polyethylene glycol/capsaicin@chitosan (PEG/CAP@CS), polyvinyl alcohol (PVA)/CAP@CS and alginate (ALG)/CAP@CS multilayer films are prepared with controlling antimicrobial properties in marine environments. There are 23.70, 23.35 and 22.06 ppb CAP releasing from (PVA/CAP@CS) 20 , (PEG/CAP@CS) 20 and (ALG/CAP@CS) 20 films after immersing in pH 4 solutions for 60 days, while only 13.07, 12.95 and 11.55 ppb CAP have been found in alkaline solutions after immersing for the same time, respectively. All these three types of films exhibit extraordinary pH responsive properties. They can control the CAP release at a low level in alkaline solutions, and make the CAP release fast in acid solutions. Moreover, the antibacterial properties against P.aeruginosa are outstanding about 95.84%, 95.0% and 96.91% for (PVA/CAP@CS) 20 , (PEG/CAP@CS) 20 and (ALG/CAP@CS) 20 films, respectively. The bacteriostasis of (ALG/CAP@CS) 20 film keeps 92.73% after 60 days in alkaline solution, which means it is steadily controlled in the marine environment. Although with similar antibacterial properties to those of (PEG/CAP@CS) 20 film, (PVA/CAP@CS) 20 film displays the maximum decrease with about 92% in acid solution after 60 days. The ALG/CAP@CS film with the best-controlled release performance and long-term antibacterial properties provides novel guidance for developing new antifouling coatings application in the marine environment.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
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IF 4.784
Xinxin Yang,Zhaoshuang Li,He Liu,Lina Ma,Xujuan Huang,Zhaosheng Cai,Xu Xu,Shibin Shang,Zhanqian Song
N-vinylcaprolactam (NVCL) is a temperature-responsive monomer, which is widely used for preparing responsive hydrogels. However, poor water solubility of NVCL necessitates the use of emulsifiers for better dispersion. Hydrolyzed epoxy soybean oil-grafted hydroxyethyl cellulose (H-ESO-HEC) polymeric emulsifier has excellent emulsifying properties, and the carboxyl groups afford pH-responsiveness to the hydrogels. A novel temperature- and pH-responsive cellulose-based hydrogel was prepared by combining NVCL and H-ESO-HEC. The hydrogel morphology, thermal stability , and swelling capacity were characterized, and it was also used as a dual-responsive drug preservative carrier. Scanning electron microscopy and thermogravimetric analysis confirmed the porous structure and good thermal stability, respectively, of the hydrogel. The hydrogel displayed a temperature- and pH-dependent swelling behavior and improved swelling capacity. The swelling behavior agreed well with the Korsmeyer-Peppas model and Schott's second-order kinetic model. The dual-responsive hydrogel has significant potential in the drug delivery systems owing to its biocompatibility and temperature and pH sensitivity.
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LANGMUIR
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2019
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IF 3.683
Sihui He,Jiantao Yu,Fangfang Wang,Leilei Tian
Intracellular pH is a vital parameter which can reflect the physiological process, and the detection of intracellular pH with a high signal-to-noise ratio (SNR) remains a challenge. Compared to pH biosensors based on a single-wavelength signal, it is much easier to obtain better sensitivity and higher SNR from the biosensors by two-wavelength ratiometric signals. In this study, we used DNA-grafted graphene oxide (GO) to ratiometrically detect intracellular pH ranging from basic to acidic. A high SNR with a 35-fold difference in the ratiometric output has been achieved through careful optimization: (1) A high DNA conjugation yield of 45% has been gained through utilizing the partial double-stranded assembly strategy. (2) Herring sperm DNA (HSD) plays an important role in improving the sensitivity of the nanosystem by purifying and passivating the surface of GO; therefore, the concentration of HSD has been optimized to pursue the most sensitive ratiometric response. Apart from the ultrahigh SNR, fabricated GO-AR-Cy5/IFO-Cy3 exhibited excellent stability and biocompatibility in biological environments. Further experiments demonstrated that the nanosystem worked well in live cells in response to pH changes. It is possible to distinguish small pH differences and realize quantitative detection based on ratiometric fluorescence imaging by laser scanning confocal microscope analysis, which makes the nanosystem a promising candidate for further biological study and clinical applications.
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CATALYSIS LETTERS
·
2019
·Vol. 149
·期 5
·1197-1210
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IF 2.372
Wang Lina,Guo Tong,Sun Sen,Wang Yan,Chen Xiaoling,Zhang Kangning,Zhang Dongxia,Xue Zhonghua,Zhou Xibin
Abstract The electrocatalytic activity of transition metal dichalcogenides (TMDs) is largely dependent on the exposed massive active sites and electrical conductivity of the catalysts. In this work, a tree-like nanocomposite (NiS 2 /MoS 2 -RGO) which is composed of bimetal sulfide (NiS 2 /MoS 2 ) nanocomposites uniformly anchored on the surface of reduced graphene oxide (RGO) was successfully synthesized. As a catalytic material for the hydrogen evolution reaction (HER), the NiS 2 /MoS 2 -RGO composites exhibit significantly enhanced electrocatalytic activity and impressive long-term stability for the hydrogen evolution reaction over a wide pH range. The tree-like NiS 2 /MoS 2 -RGO nanocomposites afford a current density (η 10 ) of 10 mA/cm 2 at small overpotentials of 172, 144 and 229 mV, and have a small Tafel slope of 51, 82 and 103 mV/dec in acidic, alkaline and neutral solution, respectively. Further studies reveal that the effective activities benefit from the abundant active edge sites and defects of NiS 2 /MoS 2 nanocomposites and the excellent conductivity of RGO. Graphical Abstract
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NEW JOURNAL OF CHEMISTRY
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2019
·Vol. 43
·期 12
·4757-4764
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IF 3.069
Yunfan Yin,Qianghua Wu,Qingxian Liu,Longchao Du
The greenhouse gas carbon dioxide was converted to an oligomeric poly(propylene carbonate)-diol by a high activity salen–Co(III) catalyst. The new mussel biomimetic hydrogel was synthesized by the reaction of poly(propylene carbonate)-diol with 1,6-hexamethylene diisocyanate followed by lysine dopamine as a chain extender. DSC tests indicate that the hydrogel has two Tg peaks, and they gradually become compatible upon increasing the molecular weight of poly(propylene carbonate)-diol. The TGA curve shows that the hydrogel gradually degrades with the degradation of the dopamine side chain, the poly(propylene carbonate) backbone and the polyurethane backbone. UV-vis spectroscopy showed that when mixed with Fe3+, Fe3+ has different complex numbers with the hydrogel at different pH values, accompanied with color changes. Rheological tests show that the stronger the alkalinity, the greater the elastic modulus of the hydrogel. SEM confirmed the cross-linking structure of the hydrogel. The numerous catechol groups impart good cell affinity and bio-tissue adhesion to the hydrogel and promote tissue adhesion and integration. By using CO2, the biomimetic material can reduce greenhouse gas emissions, which will have broad application prospects.
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International Journal of Polymeric Materials and Polymeric Biomaterials
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2019
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IF 2.263
You Zhou,Bining Qiu,Xueqiong Yin,Haifang Liu,Li Zhu
Cough variant asthma (CVA) is well-known as a subtype of asthma that is characterized by a chronic cough. Roxithromycin (ROX) and theophylline (TH) have a synergistic effect on CVA. In this study, concomitant drugs-loaded microcapsules (CDM) of ROX and TH were prepared by spray drying with amphiphilic methylcellulose (MC) and sodium Alginate (Alg) as the wall materials. The preparation conditions and wall materials components had been optimized and MC/Alg/MC had the highest encapsulation efficiency. With MC/Alg/MC as the wall material, microcapsules of concomitant drugs had higher drug loading than those of the single drug. CDM expressed obvious pH-sensitive controlled-release behavior. After 12 h releasing, the cumulative release of ROX and TH at pH 1.5 was 21.07% and 22.31%, 73.14% and 97.52% at pH 7.4, respectively. The antibacterial efficacy of pure drugs and CDM further proved that controlled-release was achieved in CDM. Cytotoxicity test on neutrophils also confirmed that CDM were less toxic to cells than the pure drugs.
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