SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Shi Gang Liu,Lei Han,Na Li,Yu Zhu Fan,Yu Zhu Yang,Nian Bing Li,Hong Qun Luo
The development of ratiometric fluorescent strategy is very significant and challenging in bioanalysis. Herein, graphitic carbon nitride (g-C 3 N 4 ) nanosheets and cobalt oxyhydroxide (CoOOH) nanoflakes are exploited for ratiometric fluorescence assay of alkaline phosphatase (ALP) activity. In the g-C 3 N 4 /CoOOH nanohybrid, g-C 3 N 4 nanosheets serve as a signal unit and the CoOOH nanoflakes function as a recognition element, and initially, the fluorescence of g-C 3 N 4 is quenched by the CoOOH nanoflakes. In the absence of target, the CoOOH nanoflakes of the nanohybrid system are able to oxidize o-phenylenediamine (OPD), and the resultant oxidation product (OxOPD) quenches the blue emission of g-C 3 N 4 and meanwhile emits orange fluorescence which acts as another signal element. However, an efficient redox reaction between ascorbic acid (AA) and CoOOH can cause decomposition of the CoOOH nanoflakes, and additionally, ALP can catalytically hydrolyze L-ascorbic acid-2-phosphate (AAP) to generate AA. Thus, in the presence of target, the CoOOH nanoflakes are destroyed by AA preferentially and the OPD is rarely oxidized to OxOPD, accompanied with strong blue emission of g-C 3 N 4 and weak orange fluorescence from OxOPD. Target-dependent dual-signal change made the ratiometric assay possible, and also AA-induced signal variation was investigated and attributed to the stronger reducing capacity of AA than OPD. The ratiometric sensing platform for ALP activity assay provides a new perspective for the applications of two-dimensional nanomaterials to develop novel and sensitive biosensors.
✓ 已验证
产品关联
DOI
高影响因子
ChemSusChem
·
2018
·Vol. 12
·期 4
·944-954
·
IF 7.411
Shi Qiu,Xuan Guo,Yong Huang,Yunming Fang,Tianwei Tan
Graphical Lignin first : A flexible lignin-first biorefinery could be developed by task-specific catalyst design for hemicellulose retention or feedstock extension. Mo x C/carbon nanotube (CNT) is found to be a promising catalyst for the retention of hemicellulose by cleavage of the bonds between lignin and carbohydrates with high selectivity. Ru/CMK-3 achieves the extension of the feedstock for the lignin-first biorefinery from hardwood to softwood. A catalytic reductive fractionation method for lignocellulosic biomass, termed lignin-first biorefinery, has emerged, which emphasises preferential depolymerization of the protolignin. However, in most studies, the lignin-first biorefinery is only effective for hardwood that has a high syringyl/guaiacol (S/G) ratio of lignin building blocks, and the degradation of hemicellulose also takes place simultaneously to a certain degree. In this study, two task-specific catalysts were developed to realize hemicellulose retention and feedstock extension through the development of an objective performance–structure relationship. It is found that Mo x C/carbon nanotube (CNT) is highly selective in the cleavage of bonds between carbohydrates and lignin and ether bonds in lignin during the catalytic reductive fractionation of hardwood, leading to a carbohydrate (both cellulose and hemicellulose) retention degree in the solid product close to the theoretical maximum and a delignification degree as high as 98.1 %. Ru/CMK-3 is demonstrated to be effective in the catalytic reductive fractionation of softwood and grass, resulting from its weak acidity and high mesoporosity.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Mengli Xu,Linyu Wang,Yi Xie,Yonghai Song,Li Wang
Here, a covalent organic framework with multiple redox-active state synthesized by amine-aldehyde condensation reaction between 4,4′,4′'-(1,3,5-triazine-2,4,6-triyl) trianiline and 2,5-dihydroxy terethaldehyde (COF DHTA-TTA ) was used as novel electrochemical sensing and biosensing platform at first time. The COF DHTA-TTA was demonstrated to be two-dimensional nanosheets with highly ordered conjugated structure and uniform mesopores about 3.67 nm. Electrochemical studies revealed that a ratiometric electrochemical sensor could be constructed by using COF DHTA-TTA itself as electroactive materials to determine hydrogen peroxide (H2O2) and pH level based on both current and potential signals. The single electrochemical sensor could monitor H2O2 concentration from 5.66 μM to 400 μM and pH level ranging from 11.0 to 3.0. Considering that the COF DHTA-TTA had good catalytic activity for oxygen reduction reaction in 0.2 M PBS (pH = 7.0), glucose oxidase was further loaded on COF DHTA-TTA via its nanosized pores and abundant active sites originated from N-doped skeleton, and the glucose biosensor exhibited good performances for glucose detection from 1.26 μM to 6.0 mM at −0.30 V, as well as from 0.60 μM to 6.0 mM at −0.53 V. The work provided good examples to construct electrochemical sensors based on redox-active COF.
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2018
·
IF 11.384
Yue Yan,Zihao Zhang,Seong-Min Bak,Siyu Yao,Xiaobing Hu,Zulipiya Shadike,Chi-Linh Do-Thanh,Feng Zhang,Hao Chen,Xilei Lyu,Kequan Chen,Yimei Zhu,Xiuyang Lu,Pingkai Ouyang,Jie Fu,Sheng Dai
Chemocatalysis of sugars to methyl lactate (MLA) exhibits great advantages over the conventional fermentation approach because of its higher productivity and cost-effective separation process. However, widely used supported metal oxide catalysts suffer from deactivation resulting from sintering during the reaction and removal of coke at high temperatures. Herein, we report ultrasmall cobalt oxide clusters (∼1.7 nm) stabilized within silicalite-1 crystals catalyst (CoO@silicalite-1), exhibiting superior catalytic activity and resistance to sintering for the conversion of fructose into methyl lactate. HAADF-STEM, EDS-mapping, and XRD experiments identify the existence of confined CoO clusters. XANES and Raman spectra demonstrated the covalent interaction between CoO and silicalite-1. Thanks to the ultrasmall CoO particle size (∼1.7 nm), the CoO@silicalite-1 affords nearly 100-fold higher Co-mass-based activity (mg MLA/mg Co) compared with CoO or Co3O4 particles outside the silicalite-1 framework. More importantly, this catalyst exhibits good reuse performance via the removal of coke with facile calcination.
✓ 已验证
产品关联
DOI
高影响因子
TOXICOLOGY AND APPLIED PHARMACOLOGY
·
2018
·
IF 3.616
Lili Wu,Yulian Chen,Han Liu,Zhikun Zhan,Zhi Liang,Tao Zhang,Zheng Cai,Ling Ye,Menghua Liu,Jie Zhao,Shuwen Liu,Lan Tang
Aggravating effect of probenecid (a traditional anti-gout agent) on emodin-induced hepatotoxicity was evaluated in this study. 33.3% rats died in combination group, while no death was observed in rats treated with emodin alone or probenecid alone, indicating that emodin-induced (150 mg/kg) hepatotoxicity was exacerbated by probenecid (100 mg/kg). In toxicokinetics-toxicodynamics (TK-TD) study, aspartate aminotransferase (AST) and systemic exposure (area under the serum concentration-time curve, AUC ) of emodin and its glucuronide were significantly increased in rats after co-administrated with emodin and probenecid for 28 consecutive days. Results showed that the increased AUC (increased by 85.9%) of emodin was mainly caused by the decreased enzyme activity of UDP-glucuronosyltransferases (UGTs, decreased by 11.8%–58.1%). In addition, AUC of emodin glucuronide was increased 5-fold, which was attributed to the decrease of multidrug-resistant-protein 2 (MRP2) protein levels (decreased by 54.4%). Similarly, in vitro experiments proved that probenecid reduced the cell viability of emodin-treated HepG2 cells through inhibiting UGT1A9, UGT2B7 and MRP2. Our findings demonstrated that emodin-induced hepatoxicity was exacerbated by probenecid through inhibition of UGTs and MRP2 in vivo and in vitro , indicating that gout patients should avoid taking emodin-containing preparations in combination with probenecid for a long time.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 61
·34877-34882
·
IF 2.936
Xue Han,Zhixin Qin,Mengyao Zhao,Jiajia Song,Fei Qu,Fengli Qu,Rong-Mei Kong
The illegal adulteration of melamine in dairy products for false protein content increase is a strong hazard to human health. Herein, a simple and sensitive colorimetric method was developed for the quantification of melamine in dairy products based on a Cu2+-hydrogen peroxide (H2O2)-3,3′,5,5′-tetramethylbenzidine (TMB) system. In this strategy, Cu2+ exhibits peroxidase-like activity and can catalyze the oxidation of TMB to oxidized TMB (oxTMB) in the presence of H2O2 with a blue colour change of the solution. However, the presence of melamine quickly interacts with H2O2 leading to the consumption of H2O2 and thus strongly hinders the oxidation of TMB. Under the optimal conditions, the absorbance change of oxTMB has a linear response to the concentration of melamine from 1 to 100 μM with a detection limit of 0.5 μM for melamine. The proposed method has many merits including more simplicity, good selectivity, and more cost-effectiveness without using any nanomaterials. The method was further successfully applied to detect melamine in dairy products including milk and infant formula powder.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Fuping Li,Zhuoli Xu,Kang Zhao,Yufei Tang
ZrB 2 -ZrC composite nanofibers were fabricated by electrospinning and carbothermal reduction. The morphology, phase composition and interface were characterized. The fabricated ZrB 2 -ZrC composite nanofibers are uniform and the diameter is about 100 nm. The effects of heat-treatment temperature, n(B)/n(Zr) and n(C)/n(Zr) on the microstructure and phase composition of composite nanofibers were systematically investigated. The results shows heat-treatment temperature has influence on the phase composition and grain size of the ZrB 2 -ZrC composite nanofibers. The content of ZrC in the ZrB 2 -ZrC composite nanofibers can be adjusted by the value of n(B)/n(Zr) in the precursors. As n(B)/n(Zr) equal to 3.5, the mass ratio between ZrB 2 and ZrC is about 48:52 which is very close to the eutectic composition of ZrB 2 -ZrC composites. The value of n(C)/n(Zr) also affects the phase composition of composite nanofibers. Reaction process and phase evolution during heat-treatment were studied based on analysis of reaction thermodynamics. The value of n(B)/n(Zr) influences the phase evolution during fabrication of ZrB 2 -ZrC composite nanofibers. The tensile mechanical properties were tested, indicating that the addition of ZrC has the ability to improve the plasticity of ZrB 2 .
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2018
·
IF 4.946
Li Wang,Timin Shan,Bing Xie,Chen Ling,Shuang Shao,Peng Jin,Yonghua Zheng
Glycine betaine (GB) treatment is useful to reduce chilling injury (CI) of several kinds of fruits including peach. However, the regulatory mechanism remains unknown. In this study, peach fruit was treated with 10 mmol L −1 GB solution for 10 min. The effects of GB treatment on CI, phenolic and soluble sugar metabolism were investigated in this study. Moreover, phenylpropanoid and soluble sugar content, and enzyme activities associated with phenolic and sugar metabolisms were also measured. The results showed that GB reduced CI and maintained high levels of total phenolic and flavonoid content. The activities of phenylpropanoid metabolism-related enzymes were significantly enhanced by GB. Higher content of sucrose and lower contents of fructose and glucose were observed in GB-treated fruits. Therefore, our results showed that GB could enhance chilling tolerance of peach through regulating phenolic and sugar metabolisms, and maintaining high levels of individual phenolic and sucrose content.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Nano
·
2018
·
IF 13.709
Yaxin Chen,Liluo Shi,Qiong Yuan,Ang Li,Shaozhuan Huang,Hui Ying Yang,Xiaohong Chen,Jisheng Zhou,Huaihe Song
Although nucleation and crystallization in solution-processed materials synthesis is a natural phenomenon, the morphology design of graphene nanosheets by controlling the dual crystallization has not been established. In this work, we systematically demonstrate how the dual crystallization of ice and potassium chloride induces the morphological variation of the freeze-dried scaffold from fractal structure toward stepped sheet-like structure. A denim-like graphene nanosheet (DGNS) has been fabricated by annealing the F127-coated stepped sheet-like scaffold in nitrogen. DGNS shows parallel and straight stripes with an average stripe spacing of 10 nm. When used as a lithium-ion battery anode, DGNS possesses a superhigh reversible capacity of 1020 mAh g–1 at the current density of 1 A g–1 after 600 cycles. This work reports the control of dual crystallization of ice and salt crystals and provides an efficient way to design the morphology of two-dimensional materials by adjusting the crystallization.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENERGY
·
2018
·
IF 4.968
Wenjing Yuan,Anjian Xie,Ping Chen,Fangzhi Huang,Shikuo Li,Yuhua Shen
Finding an effective approach to prepare low-cost metal-free catalysts with excellent catalytic performance for the oxygen reduction reaction (ORR) is a crucial challenge for the commercialization of fuel cells. Herein, a novel and effective combustion approach was designed in order to construct the three-dimensional porous carbon foam and followed by heat treatment in an NH 3 atmosphere. In the combustion process , sucrose was used as the carbon source to produce the carbon framework, sodium bicarbonate as the pore-foaming agent to form the porous structure . This synthetic route is novel, cost-effective and without using any templates, expensive equipment as well as highly toxic chemical reagents. Compared with the control samples, the typical product exhibits the excellent catalytic activity in terms of not only a positive onset potential and high current density , but also low H 2 O 2 yield and approximate four-electron reaction pathway in alkaline media . The reason may be attributed to the synergistic effect of the three-dimensional porous structure, high BET surface area (up to 1216 m 2 g −1 ) and effective nitrogen-doping of the product. In addition, the novel method is of great importance, which may guide future efforts for the development of other porous carbon-based materials for applications in multi-fields.
✓ 已验证
产品关联
DOI
高影响因子
BIOSENSORS & BIOELECTRONICS
·
2018
·
IF 8.173
Songyue Lin,Wendou Feng,Xiaofei Miao,Xiangxin Zhang,Sujing Chen,Yuanqiang Chen,Wei Wang,Yining Zhang
Flexible and implantable glucose biosensors are emerging technologies for continuous monitoring of blood-glucose of diabetes. Developing a flexible conductive substrates with high active surface area is critical for advancing the technology. Here, we successfully fabricate a flexible and highly sensitive nonenzymatic glucose by using DVD-laser scribed graphene (LSG) as a flexible conductively substrate. Copper nanoparticles (Cu-NPs) are electrodeposited as the catalyst. The LSG/Cu-NPs sensor demonstrates excellent catalytic activity toward glucose oxidation and exhibits a linear glucose detection range from 1 μM to 4.54 mM with high sensitivity (1.518 mA mM −1 cm −2 ) and low limit of detection (0.35 μM). Moreover, the LSG/Cu-NPs sensor shows excellent reproducibility and long-term stability. It is also highly selective toward glucose oxidation under the presence of various interfering species. Excellent flexing stability is also demonstrated by the LSG/Cu-NPs sensor, which is capable of maintaining 83.9% of its initial current after being bent against a 4-mm diameter rod for 180 times. The LSG/Cu-NPs sensor shows great potential for practical application as a nonenzymatic glucose biosensor. Meanwhile, the LSG conductive substrate provides a platform for the developing next-generation flexible and potentially implantable bioelectronics and biosensors.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ELECTROCHIMICA ACTA
·
2012
·
IF 3.832
Xiaohui Wu,Xiaoting Hong,Zhiping Luo,K.S. Hui,Hongyu Chen,Junwen Wu,K.N. Hui,Laisheng Li,Junmin Nan,Qiuyun Zhang
Novel mesoporous carbon has been synthesized using rod-like nano-hydroxyapatite (HA) particles as templates, sucrose as carbon precursor by polymerizing, carbonizing and the removal of templates with HCl solution. In the process, HA not only acted as an endotemplate but also an exotemplate producing micropores and mesopores. Subsequently, mesoporous carbon was modified by HNO 3 solution with different concentration. The morphology, pore structure, and surface functional groups of the as-obtained samples are analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller method (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The electrochemical performance for electrochemical capacitors is evaluated in a 1 M H 2 SO 4 aqueous solution. The results manifest that the structrue of resultant carbon with a high surface area (719.7 m 2 g −1 ) and large pore volume (1.51 cm 3 g −1 ) is the replica of HA. After modification, the surface area and pore volume mesoporous carbons slightly decrease, while their electrochemical performance have been significantly improved with the increase of the capacitance from 125.7 to 170.1 F g −1 and a non-decayed cycle life over 5000 cycles for HA-C-0.15N.
✓ 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）