Biosensors-Basel
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2023
·Vol. 13
·期 10
·932
·
IF 5.4
Gang Peng,Mengxue Guo,Yuting Liu,Han Yang,Zuorui Wen,Xiaojun Chen
Hg2+, a highly toxic heavy metal, poses significant environmental and health risks, necessitating rapid detection methods. In this study, we employed an electrochemical aptasensor for rapid and sensitive detection of Hg2+based on DNA strands (H2 and H3) immobilized graphene aerogels-Au nanoparticles (GAs-AuNPs) hybrid recognition interface and exonuclease III (Exo III)-mediated cyclic amplification. Firstly, Gas-AuNPs were modified on the surface of the ITO electrode to form a sensing interface to increase DNA loading and accelerate electron transfer. Then, DNA helper was generated with the addition of Hg2+via Exo III-mediated cycling. Finally, the hairpin structures of H2 and H3 were opened with the DNA helper, and then the methylene blue (MB) functionalized DNA (A1 and A2) combined with the H2 and H3 to form an H-shaped structure. The current response of MB as an electrochemical probe was proportional to the concentration of Hg2+. Under optimal conditions, the aptasensor showed excellent performance for Hg2+, achieving a linear range from 1 fM to 10 nM and a detection limit of 0.16 fM. Furthermore, the aptasensor was used to detect Hg2+in spiked milk samples, achieving a high recovery rate and demonstrating promising application prospects.Keywords:graphene aerogels–Au nanoparticles;Hg2+;H-shaped;aptasensor;milk sample
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Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Junyong He,Ya Yang,Peidong Hong,Yulian Li,Chao Xie,Zijian Wu,Minqiang Li,Lingtao Kong
The use of peroxymonosulfate (PMS) activation to eliminate organic contaminants is a promising technology to purify water owing to its strong reactivity. However, because of the existed rate limiting step, the performance of PMS activation was restrained and required external energy consumption. Therefore, a new strategy was proposed to solve this problem by preparing catalysts with abundant electron-rich sites and electron traps to accelerate PMS activation. In this research, a novel MnCeO x -H catalyst with rich surface oxygen vacancies was firstly synthesized to accelerate the transfer of electrons among the catalysts, oxidant and pollutants. The contaminants were rapidly eliminated in the MnCeO x -H/PMS system, while the reaction rate constant of MnCeO x -H/PMS system was 30 times higher than that of CeO 2 /PMS system. The surface oxygen vacancies were able to adsorb and trap PMS, then the free electrons of oxygen vacancies would reduce PMS and produced HO•, 1 O 2 and SO 4 •- , while 1 O 2 played a major role. The contaminants which acted as electron-donors in this system were adsorbed at Mn, Ce sites, achieving effective conversion recycling of Ce(IV)/Ce(III), Mn(III)/Mn(II) and Mn(IV)/Mn(III). This discovery is believed to inaugurate a novel way for designing powerful electron-rich sites and electron traps to accelerate PMS activation for contaminants degradation.
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MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2023
·Vol. 224
·期 23
·2300304
·
IF 2.5
Mingzhao Li,Jia Wang,Anjun Qin,Ben Zhong Tang
Hyperbranched polymers have been widely applied in various fields because of their good solubility, high reactive end groups, and low viscosity, etc. Therefore, it is of great importance to develop new strategies to build multifunctional hyperbranched polymers with novel architectures. In this work, a C(sp 3 )─H activation-based polymerization of internal alkynes and bifunctional secondary amines is successfully established, and multifunctional hyperbranched polyamines (hb-PAs) with 100% E -isomers and high molecular weights ( M w up to 76 500) are prepared in good yields (up to 82%). The hb-PAs containing tetraphenylethylene moiety show unique aggregation-enhanced emission properties and can be used for explosive detection with a low limit of detection (9.14 × 10 −8 m ). Notably, the hb-PAs display high refractive indices (up to 1.7607) that can be further modulated to 1.7825 by the coordination of its peripheral ethynyl group with metallic cobalt. Moreover, the hyperbranched structure endows the hb-PAs with much better properties than their linear counterparts, such as higher photoluminescence quantum yields and refractive indices. In addition, the hb-PAs can be modified by a C(sp 3 )─H activation reaction of internal alkynes and alcohols. This work not only prepares a series of functional nitrogen-containing hyperbranched polymers but also promotes the application of C(sp 3 )─H activation in polymer chemistry.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Zhengqing Cai,Yougui Song,Xibiao Jin,Chong-Chen Wang,Haodong Ji,Wen Liu,Xianbo Sun
A highly solar active AgBr/h-MoO 3 composite was constructed by a facile precipitation method, and the charge separation tuning was achieved by photoreduction of AgBr. The photoreduced Ag 0 on AgBr/h-MoO 3 acted as charge transfer bridge to form Z-scheme heterostructure, while the high degree of Ag reduction converted the material into type-II heterostructure. The synthesized optimal material promoted charge separation and visible light activity due to the incorporation of highly solar active AgBr, which showed ca. 2 times activity on trimethoprim (TMP) degradation than h-MoO 3 . The contribution of reactive species on TMP degradation followed the order of O 2 − > 1 O 2 > h + , which agree well with the proposed charge separation mechanism. The photocatalytic degradation mechanism of TMP was proposed based on the radical quenching, intermediate analysis and DFT calculation. The toxicity analysis based on QSAR calculation showed that part of the degradation intermediates are more toxic than TMP, thus sufficient mineralization are required to eliminate the potential risks of treated water. Moreover, the material showed high stability and activity after four reusing cycles, and it is applicable to treat contaminants in various water matrix. This work is expected to provide new insight into the charge separation tuning mechanism for the AgX based heterojunction , and rational design of highly efficient photocatalysts for organic contaminants degradation by solar irradiation.
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Materials
·
2021
·Vol. 14
·期 11
·2741
·
IF 3.623
Pengcheng Lv,Ruihong Meng,Zhongyang Mao,Min Deng
In this study, the hydrated sodium aluminosilicate material was synthesized by one-step hydrothermal alkaline desilication using fly ash (FA) as raw material. The synthesized materials were characterized by XRD, XRF, FT-IR and SEM. The characterization results showed that the alkali-soluble desilication successfully had synthesized the sodium aluminosilicate crystalline (N-A-S-H) phase of sodalite-type (SOD), and the modified material had good ionic affinity and adsorption capacity. In order to figure out the suitability of SOD as an adsorbent for the removal of ammonium and phosphorus from wastewater, the effects of material dosing, contact time, ambient pH and initial solute concentration on the simultaneous removal of ammonium and phosphorus are investigated by intermittent adsorption tests. Under the optimal adsorption conditions, the removal rate of ammonium was 73.3%, the removal rate of phosphate was 85.8% and the unit adsorption capacity reached 9.15 mg/L and 2.14 mg/L, respectively. Adsorption kinetic studies showed that the adsorption of ammonium and phosphorus by SOD was consistent with a quasi-secondary kinetic model. The adsorption isotherm analysis showed that the equilibrium data were in good agreement with the Langmuir and Freundlich model. According to thermodynamic calculations, the adsorption of ammonium and phosphorus was found to be a heat-absorbing and spontaneous process. Therefore, the preparation of SOD by modified FA has good adsorption properties as adsorbent and has excellent potential for application in the removal of contaminants from wastewater.Keywords:N-A-S-H;sodalite;simultaneous removal;ammonium;phosphorus
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Materials
·
2020
·Vol. 13
·期 10
·2340
·
IF 3.057
Yongzhe Fan,Huazhen Yang,Haisheng Fan,Qi Liu,Chuang Lv,Xue Zhao,Mingxu Yang,Jianjun Wu,Xiaoming Cao
The hexagonal boron nitride (h-BN) nanosheets modified by silane coupling agent (KH560) were doped into acrylic acid coating on the surface of galvanized steel to improve its corrosion resistance. H-BN nanosheets modified by KH560 were prepared and characterised by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. The corrosion resistance of the acrylic acid coatings was measured by electrochemical testing. The results show that the corrosion current density of the coating with modified h-BN nanosheets was reduced from 2.2 × 10−5A/cm2to 2.3 × 10−7A/cm2compared with the acrylic acid coating. The impedance of the composite coating with modified h-BN is 4435 Ω·cm2, higher than the BNNS coating (2500 Ω·cm2) and the acrylic acid coating (1500 Ω·cm2). This is due to the physical barrier and electrical insulation properties of the hexagonal boron nitride (h-BN) nanosheets.Keywords:hot-dip galvanized steel;boron nitride nanosheet;corrosion resistance;acrylic coating
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Journal of Central South University
·
2020
·Vol. 26
·期 11
·2974-2986
·
IF 1.249
Xu Si-quan,Pan Dong-hui,Xiao Guo-min
With the aim of achieving a high 5-hydroxymethylfurfural (HMF) yield from glucose with H-ZSM-5 catalyst at low cost, three inexpensive biphasic reaction systems, H 2 O—tetrahydrofuran (THF), H 2 O—2-methyltetrahydrofuran (MeTHF) and H 2 O’2-butanol, were discovered and proved to be particularly effective in promoting the formation of HMF from glucose over H-ZSM-5 zeolite. In order to determine the optimal process conditions, the effects of various experimental variables, such as reaction temperature, reaction time, catalyst dosage, volume of organic solvent, as well as inorganic salt type on glucose conversion to HMF in three systems were investigated in detail. It was found that under optimal reaction conditions, H 2 O—THF, H 2 O—2-butanol and H 2 O—MeTHF allowed the glucose dehydration process to achieve HMF yields of up to 61%, 59%, and 50%, respectively. Moreover, in the three biphasic systems, the H-ZSM-5 catalyst was also demonstrated to maintain excellent stability. Thus, the catalytic approach proposed in this paper can be believed to have potential prospects for industrially efficient and low-cost production of HMF.
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ChemSusChem
·
2019
·Vol. 12
·期 16
·3871-3877
·
IF 7.804
Dan Wu,Xing Yu,Xinqing Chen,Gan Yu,Kun Zhang,Minghuang Qiu,Wenjie Xue,Chengguang Yang,Ziyu Liu,Yuhan Sun
Graphical Stacks on ! H-type MFI zeolite catalysts with a unique stacked structure are synthesized in a one-pot procedure in the presence of NH 4 F with the help of zeolite confinement through a solvent-free route without further ion-exchange procedures. The catalysts display excellent catalytic performance in methanol-to-gasoline reactions. H-type aluminosilicate zeolites are extensively used as solid-acid catalysts and support materials in industrial catalysis. However, the conventional synthesis methods involving hydrothermal syntheses and ion-exchange processes suffer from severe water pollution and toxic gas emissions. Herein, H-type MFI zeolite catalysts with a unique stacked structure were directly synthesized in the presence of NH 4 F and with the help of zeolite confinement through a solvent-free route without further ion-exchange procedures. A range of ex situ and in situ characterization procedures were used to provide evidence of the simultaneous use of pre-made ZSM-5 and NH 4 F as a confined Al source and mineralizer, respectively. The confined zeolite framework of ZSM-5 prevented the formation of AlF x species between NH 4 F and Al atoms, ensuring that the prepared samples had desirable acidic properties. Moreover, the resulting morphology could be controlled by using different silica substrates. The obtained H-type MFI zeolites showed excellent catalytic performance in methanol-to-gasoline reactions owing to their unique structure and directly exposed acidic sites. The developed one-pot strategy provides an alternative method for the facile synthesis of H-type zeolites with defined morphology.
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Journal of the American Chemical Society
·
2015
·
IF 12.113
Xiao-Li Pei,Yang Yang,Zhen Lei,Shan-Shan Chang,Zong-Jie Guan,Xian-Kai Wan,Ting-Bin Wen,Quan-Ming Wang
The activation of C(sp3)–H bonds is challenging, due to their high bond dissociation energy, low proton acidity, and highly nonpolar character. Herein we report a unique gold(I)–silver(I) oxo cluster protected by hemilabile phosphine ligands [OAu3Ag3(PPhpy2)3](BF4)4 (1), which can activate C(sp3)–H bonds under mild conditions for a broad scope of methyl ketones (RCOCH3, R = methyl, phenyl, 2-methylphenyl, 2-aminophenyl, 2-hydroxylphenyl, 2-pyridyl, 2-thiazolyl, tert-butyl, ethyl, isopropyl). Activation happens via triple deprotonation of the methyl group, leading to formation of heterometallic Au(I)–Ag(I) clusters with formula RCOCAu4Ag4(PPhpy2)4(BF4)5 (PPhpy2 = bis(2-pyridyl)phenylphosphine). Cluster 1 can be generated in situ via the reaction of [OAu3Ag(PPhpy2)3](BF4)2 with 2 equiv of AgBF4. The oxo ion and the metal centers are found to be essential in the cleavage of sp3 C–H bonds of methyl ketones. Interestingly, cluster 1 selectively activates the C–H bonds in −CH3 rather than the N–H bonds in −NH2 or the O–H bond in −OH which is traditionally thought to be more reactive than C–H bonds. Control experiments with butanone, 3-methylbutanone, and cyclopentanone as substrates show that the auration of the C–H bond of the terminal methyl group is preferred over secondary or tertiary sp3 C–H bonds; in other words, the C–H bond activation is influenced by steric effect. This work highlights the powerful reactivity of metal clusters toward C–H activation and sheds new light on gold(I)-mediated catalysis.
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JOURNAL OF MATERIALS SCIENCE
·
2014
·Vol. 49
·期 22
·7730-7741
·
IF 2.305
Luo Yan-Ling,Huang Rui-Juan,Xu Feng,Chen Ya-Shao
pH-Sensitive biodegradable polymethacrylic acid- block -polylactic acid- block -polymethacrylic acid (PMAA 2 - b -PLA- b -PMAA 2 ) H-type multiblock copolymers were synthesized by atom transfer radical polymerization. The copolymer structure and molecular weight were characterized by FT-IR, 1 H NMR, and gel permeation chromatography. The physicochemical characterization revealed that the copolymers could spontaneously form spherical core–shell micelles in aqueous solution, with critical aggregation concentration of about 19.7–32.5 mg L −1 and the hydrodynamic diameters below 200 nm. Z eta potentials measurements disclosed that the copolymer micelles were negatively charged due to ionized carboxyl groups in various PBS solutions. The H-type block copolymer micelles exhibited pH- sensitivity, as expected; and the hydrophobic anticancer drugs, 10-hydroxycamptothecin, and paclitaxel, had faster release rate in PBS solution of pH 5.6–7.4 than in PBS of pH 1.4, which was important for applications in the therapy of small intestine cancers. The copolymer micelle aggregates were proved to be biodegradable, and the degradation rates changed with copolymer compositions and environmental media. The micelle drug formulation indicated pH-dependent cytotoxicity and was thus capable of effectively killing the intestinal cells while avoiding doing harm to stomach. The biodegradable pH-sensitive PMAA 2 - b -PLA- b -PMAA 2 H-type copolymer micelles can be used as water-insoluble drug targeting release carriers for targeted treatment of intestine cancers.
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Soft Matter
·
2013
·Vol. 9
·期 48
·11585-11597
·
IF 3.909
Wenlong Li,Peiyi Wu
The dynamic thermally reversible phase transition behaviour of poly(ethylene oxide) (PEO) in 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) has been investigated by calorimetric measurements (DSC) and FT-IR, in combination with perturbation correlation moving window (PCMW) and two-dimensional correlation spectroscopy (2DCOS) for the first time. A relatively high lower critical solution temperature (LCST) was observed which is different from that of conventional thermo-sensitive polymers in aqueous solution. Four types of hydrogen bonds were found in this system, among which the type I (the hydrogen bonds between the unsaturated C–H on the imidazole ring and the oxygen atoms of PEO) and type II (the hydrogen bonds between the saturated C–H on the PEO backbone and the fluorine atoms of the IL anions) ones have a more predominant influence on the phase transition. Moreover, type I plays the predominant role in both the heating and cooling process. DSC revealed that the phase transition temperature of PEO–[EMIM][BF4] solutions decreases with the increasing concentration of PEO, as well as with a decreasing scanning rate. Through PCMW, the LCST was determined to be ca. 137 °C during heating and ca. 131 °C during cooling. Finally, 2DCOS was employed to elucidate the dynamic mechanism of PEO in [EMIM][BF4], which revealed hydrogen bond disruption, chain aggregation and exclusion of IL molecules. Solutions with a low PEO concentration tend to form loosely aggregated globules, compared to the more densely aggregated globules in samples with a high PEO concentration. Additionally, it is worth mentioning that several unusual and peculiar phenomena were also observed, such as opposite frequency shifts in C–H groups, a “tail-raising” phenomenon, critical PEO concentration for the phase transition temperature, and intersection of the frequency shift curves for samples with high concentrations of PEO during cooling.
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ANALYTICAL BIOCHEMISTRY
·
2016
·
IF 2.243
Wei Zhang,Min Zhu,Feng Wang,Danhui Cao,Jennifer Jin Ruan,Weike Su,Benfang Helen Ruan
Glutamate dehydrogenase (GDH) catalyzes the oxidative deamination of L-glutamate and is important for several biological processes . For GDH inhibitor screening, we developed a novel mono-sulfonated tetrazolium salt (EZMTT), which can be synthesized using H 2 O 2 oxidation and purified easily on silica gel in large quantities. The EZMTT detection method showed linear dose responses to NAD(P)H, dehydrogenase concentration and cell numbers. In E. coli GDH assay, the EZMTT method showed excellent assay reproducibility with a Z factor of 0.9 and caused no false positives in the presence of antioxidants (such as BME). Using the EZMTT-formazan-NAD(P)H system, we showed that EGCG is a potent E. coli GDH inhibitor (IC 50 45 nM) and identified that Ebselen , a multifunctional thioredoxin reductase inhibitor, inactivated E. coli GDH (IC 50 213 nM). In cell-based assays at 0.5 mM tetrazolium concentration, EZMTT showed essentially no toxicity after a 3-day incubation, whereas 40% of inhibition was observed for WST-8. In conclusion, EZMTT is a novel tetrazolium salt which provides improved features that are suitable for dehydrogenases and real-time cell-based high-throughput screening (HTS).
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