Food Analytical Methods
·
2020
·Vol. 13
·期 7
·1433-1441
·
IF 2.667
Duan Nuo,Yang Wei,Wu Shijia,Zou Ying,Wang Zhouping
In order to monitor and respond rapidly to outbreaks of food-borne pathogens, establishing rapid and sensitive detection methods is becoming increasingly urgent. In this work, through the synthesis of copper-based metal-organic framework nanoparticles (Cu-MOF NPs) and functionalized with aptamers, we developed a colorimetric protocol to detect Escherichia coli . In a typical experimental procedure, aptamer 1 was immobilized onto microplate to act as capture probes. Cu-MOF NPs were synthesized and functionalized with streptavidin and biotinylated aptamer 2 to form the signal probes. In the presence of E. coli , aptamers on both capture and signal probes bind with E. coli and form a sandwich-type complex. The Cu-MOF NPs enable to catalyze the colorless peroxidase substrate to yield a colorimetric output signal. This peroxidase-like mimics-based colorimetric aptasensor showed a rapid and sensitive quantification of E. coli in the concentration range of 16~1.6 × 10 6 cfu/mL with a limit of quantitation (LOQ) of 16 cfu/mL and limit of detection (LOD) of 2 cfu/mL. The application of the developed assay for colorimetric measuring of milk samples was evaluated with satisfactory results. The developed Cu-MOF NPs-assisted visual method can be expected as a powerful alternative and promising tool for foodborne pathogen detection and control.
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JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 24
·10558-10571
·
IF 3.553
Zhan Wenwei,Fu Xue,Wang Feng,Zhang Wenqing,Bai Gang,Xiao Wei,Zhou Aosong,Sui Gang,Yang Xiaoping
Aromatic amine modified 3D porous graphene aerogel was prepared through chemical reduction and self-assembly of graphene oxide sheets in one step by using diaminodiphenylmethane (DDM) as a reducing agent, modifying agent, and curing agent. Subsequently, the DDM-modified graphene aerogel (DGA) was fully infiltrated with epoxy resin to obtain the DGA/epoxy composites. The abundant amine groups derived from DDM on the DGA can react with epoxy resin to strengthen the interfacial interaction, further promoted the curing behaviors by significantly lowering the reaction activation energy. The reinforcement of interfacial interaction and well-interconnected frameworks enhanced the effective transfer of stress and electrons in the resulting composites. Thus, the resulting DGA/epoxy composites exhibited excellent compressive properties and high electrical conductivity. This study presented a facile technique for preparing porous graphene aerogel, which simultaneously improved the electrical conductivity and mechanical properties of epoxy composites, and overcame the issues of dispersion and interfacial interaction of traditional nanofillers.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 3
·1-8
·
IF 6.232
Mei He,Shu Huawei,Lv Mengyu,Liu Wei,Wang Xuedong
Phenyl-modified graphitic carbon nitride nanosheets (Ph- g -C 3 N 4 NSs) were synthesized by a thermal copolymerization and ultrasonic exfoliation method. The Ph- g -C 3 N 4 NSs are used as a fluorescent assay for determination of thiram. The results of X-ray photoelectron spectroscopy, 13 C solid-state nuclear magnetic resonance and Fourier transform infrared spectra confirm that phenyl group is integrated into the heptazine network of g -C 3 N 4 . Compared to the g -C 3 N 4 NSs, the Ph- g -C 3 N 4 NSs show bigger stokes shift about 185 nm and higher fluorescence intensity. The fluorescence of Ph- g -C 3 N 4 NSs is quenched by Cu 2+ via the photo-induced electron transfer mechanism, which then recovers in the presence of thiram. The fluorescence restoring of Ph- g -C 3 N 4 NSs is correlated with the concentration of thiram. Under the optimized conditions, the fluorescent intensity of g -C 3 N 4 NSs at excitation/emission wavelengths of 310/455 nm give a linear range of 33.0–670 nM with detection limit of 9.90 nM. While fluorescent assay based on the Ph- g -C 3 N 4 NSs show the linear range of 6.70–1300 nM at excitation/emission wavelengths of 310/495 nm with detection limit of 2.01 nM.
Schematic representation of fluorescent “on-off-on” assay based on phenyl-modified graphitic carbon nitride nanosheets (Ph- g -C 3 N 4 NSs) for determination of thiram.
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高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2020
·Vol. 412
·期 8
·1915-1923
·
IF 3.637
Ge Minghao,Sun Jiaojiao,Chen Mingli,Tian Jingjing,Yin Huancai,Yin Jian
Due to its important role in tumor development and treatment, hyaluronidase (HAase) has been widely investigated in vitro and in vivo. However, such investigation was limited by the absence of sensitive and in situ detection methods. Herein, a hyaluronic acid (HA) hydrogel based on the fluorescence resonance energy transfer (FRET) effect was constructed for the detection of HAase. FITC and AuNPs were covalently coupled with two HA derivatives respectively to form a fluorescent donor-acceptor pair. In the presence of HAase, the hydrogel established by cross-linking of HA derivatives was hydrolyzed specifically. The FRET effect in the hydrogel disappeared and the fluorescence intensity increased proportionally with the changes in the concentration of the HAase. Experiments proved that the HAase sensing system had a wide response range (0.5–100 U/mL), good anti-interference, and excellent biocompatibility. When the hydrogel was used for 3D culture of lung cancer cells, in situ fluorescent response could be achieved.
Graphical abstract
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高影响因子
Scientific Reports
·
2020
·Vol. 10
·期 1
·1-12
·
IF 3.998
Akram Naeem,Guo Jia,Ma Wenlan,Guo Yuan,Hassan Afaq,Wang Jide
The exploration of advanced water treatment technologies e.g. heterogeneous photocatalysis is the most promising way to address organic pollution issues. Semiconductors based bimetallic photocatalysis with wide bandgap, have displayed splendid degradation performance in the UV light region, but their extension to the visible light/near infra-red region is still a matter of great concern. CuO, Co(OH) 2 , CoO and Co(OH) 2 /CuO nanocomposites were synthesized via simple co-precipitation method and further practiced for Rhodamine B (RhB) decomposition by introducing per-sulfate (PS) as a sacrificial agent. Results revealed that Co(OH) 2 /CuO catalyst had shown robust catalytic activity for RhB photodegradation (degradation time 8 min, k = 0.864 min −1 ) under light illumination, significantly less (12–60 times) than the other reported bimetallic catalysts. Catalyst also have verified excellent performance for a broader pH range (5–9) with excellent stability. Main reactive species responsible for the photocatalytic reaction were sulfate (SO 4 •− ) and superoxide (O 2 • ) radicals, duly verified by ESR and by using radical scavengers. With outstanding recycling abilities, this is probably the fewer successful attempt for RhB decolorization and can be highly favorable for effluent treatment by using the synergic effect of absorption and photodegradation.
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高影响因子
Nanoscale Research Letters
·
2020
·Vol. 15
·期 1
·1-10
·
IF 3.578
Shen Shuling,Wang Cheng,Sun Minquan,Jia Mengmeng,Tang Zhihong,Yang Junhe
In this work, a free-standing sodium titanate ultralong nanotube membrane for multifunctional water purification has been prepared. For obtaining this free-standing membrane with good tenacity, one-dimensional (1D) sodium titanate ultralong nanotubes with a diameter of about 48 nm and length of hundreds of micrometers were prepared from TiO 2 nanoparticles by a stirring hydrothermal method, which can be easily assembled into 2D membranes by facile vacuum filtration. After modified with methyltrimethoxysilane (MTMS), the free-standing membrane with hydrophobic surface possesses oil-water separation, self-cleaning and photocatalytic functions at the same time, which is favorable for the recovery of membrane and decontamination of various pollutants including oils, dust, and organic dyes from water. Furthermore, this membrane also exhibits excellent alkaline, acid, and corrosive salt resistance. This free-standing sodium titanate membrane with multifunction has potential applications in efficient wastewater purification and environmental remediation.
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高影响因子
MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 7
·1-12
·
IF 6.232
Kalambate Pramod K.,Dhanjai,Sinha Ankita,Li Yankai,Shen Yue,Huang Yunhui
New multi-walled carbon nanotubes supported on Ti 3 C 2 –MXene and chitosan (chit) composite film–based electrochemical sensor for ifosfamide (IFO), acetaminophen (ACOP), domperidone (DOM), and sumatriptan (SUM) have been developed. Ti 3 C 2 –MXene was synthesized by a fluoride method. Structural and chemical characterizations suggested the successful preparation of Ti 3 C 2 –MXene with clearly seen layered morphology, defined 0 0 2 diffraction peak at 7.5° and complete absence of 1 0 4 plane at 39°. The electrochemical performance of the sensor was investigated by cyclic voltammetry and adsorptive stripping differential pulse voltammetry. The Ti 3 C 2 /MWCNT/Chit modified glassy carbon electrode exhibits enhanced electrocatalytic activities toward the oxidation of target analytes. Excellent conductivity, large surface area, and high catalytic properties of the Ti 3 C 2 –MXene showed synergistic effects with MWCNTs and helped in achieving low detection limits of targets with high selectivity and reproducibility. The assay allows determination of IFO, ACOP, DOM, and SUM in the concentration ranges 0.0011–1.0, 0.0042–7.1, 0.0046–7.3, and 0.0033–61 μM with low detection limits of 0.00031, 0.00028, 0.00034, and 0.00042 μM, respectively. The sensor was successfully applied for voltammetric screening of target analytes in urine and blood serum samples with recoveries > 95.21%. Schematic illustration of the synthesis of self-assembled MXene/MWCNT/chitosan nanocomposite is given and its application to the voltammetric determination of ifosfamide, acetaminophen, domperidone, and sumatriptan described.
Graphical abstract
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FIBERS AND POLYMERS
·
2020
·Vol. 21
·期 6
·1229-1237
·
IF 1.797
Zhang Yiyi,Zhang Nan,Wang Qiang,Yu Yuanyuan,Wang Ping,Yuan Jiugang
Most modifications of wool focused on its surface due to the existence of the cuticle scales. For instance, chlorination, oxidation and protease treatments were used to break down or remove the scales. However, these modifications usually severely damaged the internal structure of wool. In this paper, a novel approach based on surface micro-dissolution was employed to modify the surface of wool to minimize the internal damage of wool, and improve the surface-related properties of wool. The micro-dissolution system used NaHSO 3 /urea to dissolve the scale layer of wool. After being micro-dissolved with NaHSO 3 /urea system, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), fluorescence microscopy, Fourier transform infrared spectroscopy (FTIR), and the Allwörden reaction were utilized to characterize the treated wool. Furthermore, felting shrinkage, strength loss and wettability of the treated wool were determined. The results showed that NaHSO 3 /urea system could dissolve the scale layer from outside to inside. The fluorescence microscopic images further indicated that low concentration of NaHSO 3 /urea system can dissolve the surface of wool without the serious damage of internal structure. Moreover, the micro-dissolution system can be controlled to dissolve the scale layer on the surface of wool slightly by adjusting the reaction conditions. The presented method is simple, easy to operate, and economical, thereby can open up new directions for the surface modification of wool.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 25
·11310-11324
·
IF 3.553
Ren Hai-Tao,Han Jing,Li Ting-Ting,Liang Yu,Jing Meng-Zhen,Jiang Si-Meng,Lin Jia-Horng,Lou Ching-Wen
Visible light response PAN@Ag–Ag 2 O/TiO 2 (PAN@AT) nanofibers with different mass ratios between Ag–Ag 2 O and TiO 2 were synthesized via a facile electrospinning technique and pH-induced precipitation reaction. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscope analyses manifest the formation of Ag–Ag 2 O/TiO 2 heterojunctions, and Ag–Ag 2 O/TiO 2 nanoparticles are evenly distributed on PAN nanofibers. The fabricated nanofibers show a highly photocatalytic performance toward As(III) oxidation under visible light, and the conversion is 92.1% after 120-min reaction at pH 5.0 in the system of PAN@AT4. Furthermore, conversion of As(III) can retain 88.6% of the original activity after repeating four cycles, indicating the good recyclability of PAN@AT4 nanofibers. Quenching experiments and electron spin resonance spectra analysis further demonstrate that the predominate active species for As(III) oxidation by PAN@AT4 are h + and · OH. The enhanced catalytic activity of PAN@AT4 is therefore ascribed to the formation of Ag–Ag 2 O/TiO 2 heterojunctions on PAN surface and the efficient separation of photoinduced electron–hole pairs. This study provides a new material to oxidize reducing pollutants [such as As(III)] and also sheds light on the fabrication of recyclable photocatalysts.
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JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2020
·Vol. 101
·期 3
·562-570
·
IF 2.008
Su Zixian,Zhao Guangying,Dou Wenchao
Abstract In this paper, monodisperse high chroma colored silica nanoparticles (SiNPs) were efficiently prepared by layer-by-layer (LbL) self-assembled technique. Poly(sodium-p-styrenesulfonate) (PSS) and Poly(ethyleneterephthalate) (PEI) were respectively used as polyanion and polycationic electrolytes. The monodisperse SiNPs with negative charge on the surface were used as the matrix. Direct dye (C.I Direct Red 224) was deposited on the SiNPs surface by means of LbL electrostatic adsorption. PEI and C.I. Direct Red 224 were electrostatically adsorbed on the surface of SiNPs. Then PSS and PEI were adsorbed on SiNPs surface to make the red SiNPs positive negative, respectively. And multilayer film-coated high chroma red SiNPs were prepared by repeating the above steps 4 times. The effects of concentration of polyelectrolyte, supporting salt (NaCl), amount of C.I Direct Red 224 and deposition time on dye coupling rate were studied. The multilayer film-coated high chroma red SiNPs were characterized using Scanning Electron Microscopy (SEM), Nano ZS potential laser particle analyzer and UV–vis spectrophotometer. The nanoparticles show good dispersibility due to the mutual repulsion of the same charge, and deep color. In addition, dense nano-film formed prevents the detachment of the dye and prevent the dye from falling off. This high chroma red SiNPs is expected to become a probe of visual marker and amplify the signal in immunoassay.
Schematic representation of the preparation of high chroma colored silica nanoparticles Poly(sodium-p-styrenesulfonate) (PSS)/Poly(ethyleneterephthalate) (PEI) multilayer membrane by layer-by-layer self-assembly. The high chroma red nanoparticles were prepared for the first time using layer-by-layer self-assembly.
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BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2020
·Vol. 43
·期 10
·1847-1858
·
IF 2.419
Zhang Han,Hua Shao-Feng,Li Cong-qiang,Zhang Lei,Fan Yun-Chang,Duan Peigao
Although graphene oxide (GO) has great potential in the field of immobilized enzyme catalysts, the detailed effects of GO with different morphological structures on immobilized enzyme are not well understood. GOs were prepared from 8000 mesh and nanoscale graphite at different reaction temperatures, and used as carriers to immobilize alpha-amylase by cross-linking method. The properties of GOs were characterized through Atomic force microscope, Fourier-transformed infrared, X-ray photoelectron spectroscopy, Raman and UV–Vis. Furthermore, the dosage of cross-linking agent, cross-linking time, optimum temperature/pH, thermal/pH/storage stability, reusability and kinetic parameters of immobilized enzymes were investigated. The results showed that the loading of alpha-amylase on GOs was 162.3–274.2 mg g −1 . The reusability experiments revealed high activity maintenance of immobilized alpha-amylase even after seven reaction cycles. Moreover, the storage stability of immobilized enzyme improved via immobilization in comparison with free one and it maintained over 70% of their initial activity after 20 days storage at 4 °C.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 22
·9414-9424
·
IF 3.553
Hu Yi,Chiang Sun-Wai,Chu Xiaodong,Li Jia,Gan Lin,He Yanbing,Li Baohua,Kang Feiyu,Du Hongda
Efficient thermal dissipation is one of the most critical factors constraining the development of modern microelectronic devices. Placing vertically aligned carbon nanotubes (VACNTs) with anisotropic thermal conductive between high-power devices and heat sink such as copper plate can improve the interfacial thermal conductance. Due to the limited contact area between CNTs and the surface of the devices, direct use of ACNTs as thermal interface material fails to meet people’s expectations. Here, we employ reduced graphene oxide (rGO) as the substrate for the growth of CNT arrays. VACNTs grown on rGO (rGO-ACNT) by chemical vapor deposition are then used as thermal conducting filler in epoxy resin. Compared with direct contact between CNT and the interface, using CNT and reduced graphene oxide junction to form contact with the surface can improve heat transfer efficiency. The resultant composite film exhibited excellent thermal conductivity at 9.62 W m −1 K −1 along the thickness direction. The obtained rGO-ACNT and its composite present higher thermal conductivity and heat transfer ability than ACNT. This strategy offers an insight into the easy preparation of flexible and highly thermal conductive composite materials, which may enable potential applications in advanced electronic devices.
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