JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
·
2014
·
IF 2.002
Jianhan Lin,Min Li,Yanbin Li,Qi Chen
Sample pretreatment is a key to rapid screening of pathogens for prevention and control of foodborne diseases. Magnetic immunoseparation is a specific method based on antibody–antigen reaction to capture the target bacteria and concentrate them in a smaller-volume buffer. The use of nano-sized magnetic particles could improve the separation efficiency of bacteria but require much higher gradient and strength magnetic field. In this study, a strong magnetic bioseparator with a mean field strength of 1.35 T and a mean gradient of 90 T/m was developed with the use of the 30 nm and 180 nm magnetic particles to specifically separate and efficiently concentrate foodborne bacterial pathogens using Escherichia coli O157:H7 as a model bacterium. The polyclonal antibodies against E. coli were evaluated using Dot ELISA analysis for their good affinity with the target bacteria and then used to modify the surface of the magnetic nanoparticles by 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) method and streptavidin-biotin binding. The magnetic particle concentrations were optimized to be 40 µg/ml and 100 µg/ml for the 30 nm and 180 nm particles, respectively, the immunoreaction time was optimized to be 45 min for both sizes of particles, and the separation times were optimized to be 60 min and 2 min for the 30 nm and 180 nm particles, respectively. The total magnetic separation time was 2 h and 1 h for the 30 nm and 180 nm particles, respectively. The experimental results demonstrated that the bioseparator with the use of either 30 nm or 180 nm immunomagnetic particles could achieve a separation efficiency of >90% for E. coli O157:H7 at the concentrations ranging from 10 2 to 10 5 cfu/ml. No obvious interferences from non-target foodborne pathogens, such as Salmonella Typhimurium and Listeria innocua , were found. For overall consideration of the consuming time, the cost, and the separation efficiency, the 180 nm magnetic particles are practical for rapid screening applications; however the 30 nm magnetic particles are preferable for specific detection applications. This immunomagnetic bioseparator can be integrated with either conventional culture methods or some rapid detection methods, such as biosensors and PCR, for more sensitive detection of foodborne pathogens.
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TALANTA
·
2014
·
IF 3.511
Xinai Zhang,Fan Zhang,Hongyin Zhang,Jianzhong Shen,En Han,Xiaoya Dong
In this paper, we report an amplified electrochemical immunoassay for Escherichia coli as indicator bacteria relevant to the quality of dairy product using the functionalized gold nanorod-based labels ({ d Ab–AuNR–FCA}). The { d Ab–AuNR–FCA} labels were designed by exploiting silica-functionalized gold nanorods (AuNR@SiO 2 ) as the carriers for immobilization of detection antibody ( d Ab) and ferrocenecarboxylic acid (FCA), in which d Ab was used for recognition of E. coli and FCA tags served as signal-generating molecule. Greatly amplified signal was achieved in the sandwich-type immunoassay when enormous FCA linked to AuNR@SiO 2 . Compared with the commercially available { d Ab–FCA}, the { d Ab–AuNR–FCA} labels exhibited a better performance for E. coli assay due to the advantages of AuNR@SiO 2 as carriers. Under optimal experimental conditions, it showed a linear relationship between the peak current of FCA and the logarithmic value of E. coli concentration ranging from 1.0×10 2 to 5.0×10 4 cfu mL −1 with a detection limit of 60 cfu mL −1 ( S / N =3), and the electrochemical detection of E. coli could be achieved in 3 h. Moreover, the proposed strategy was used to determine E. coli in dairy product (pure fresh milk, yogurt in shelf-life, and expired yogurt), and the recoveries of standard additions were in the range of 95.1–106%. This proposed strategy exhibited rapid response, high sensitivity and specificity for E. coli assay in dairy product, and could become a promising technique to estimate the quality of dairy product.
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ANALYST
·
2014
·Vol. 140
·期 2
·551-559
·
IF 3.906
Yuna Guo,Yu Wang,Su Liu,Jinghua Yu,Hongzhi Wang,Min Cui,Jiadong Huang
A novel electrochemical immunosensor assay (EIA) for highly sensitive and specific detection of Escherichia coli O157:H7 has been developed. This immunosensor is constructed by the assembly of capture antibody on SG–PEDOT–AuNPs composites modified glass carbon electrode. In the presence of target E. coli O157:H7, horseradish peroxidase (HRP)-labeled antibody is captured on the electrode surface to form a sandwich-type system via the specific identification. As a result, E. coli O157:H7 detection is realized by outputting a redox current from electro-reduction of hydrogen peroxide reaction catalyzed by HRP. In our assay, the combination of the unique properties of sulfonated graphene (SG) and gold nanoparticles (AuNPs) can not only accelerate electron transfer on electrode interface, but also provide an excellent scaffold for the conjugation of capture antibody that significantly improves the target capture efficiency and enhances the sensitivity of the biosensor. The results reveal the calibration plot obtained for E. coli O157:H7 is approximately linear from 7.8 × 10–7.8 × 106 colony-forming unit (cfu) mL−1 with the limit of detection of 3.4 × 10 cfu mL−1. In addition, the biosensor has been successfully applied to the quantitative assay of E. coli O157:H7 in synthetic samples (spring water and milk). Hence, the developed electrochemical-based immunosensor might provide a useful and practical tool for E. coli O157:H7 determination and related food safety analysis and clinical diagnosis.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2014
·Vol. 21
·期 7
·5201-5210
·
IF 2.757
Chen Xi,Yao Xiaoyan,Yu Chunna,Su Xiaomei,Shen Chaofeng,Chen Chen,Huang Ronglang,Xu Xinhua
Soil pollution by polychlorinated biphenyls (PCBs) arising from the crude disposal and recycling of electronic and electrical waste (e-waste) is a serious issue, and effective remediation technologies are urgently needed. Nanoscale zerovalent iron (nZVI) and bimetallic systems have been shown to promote successfully the destruction of halogenated organic compounds. In the present study, nZVI and Pd/Fe bimetallic nanoparticles synthesized by chemical deposition were used to remove 2,2′,4,4′,5,5′-hexachlorobiphenyl from deionized water, and then applied to PCBs contaminated soil collected from an e-waste recycling area. The results indicated that the hydrodechlorination of 2,2′,4,4′,5,5′-hexachlorobiphenyl by nZVI and Pd/Fe bimetallic nanoparticles followed pseudo-first-order kinetics and Pd loading was beneficial to the hydrodechlorination process. It was also found that the removal efficiencies of PCBs from soil achieved using Pd/Fe bimetallic nanoparticles were higher than that achieved using nZVI and that PCBs degradation might be affected by the soil properties. Finally, the potential challenges of nZVI application to in situ remediation were explored.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Zhihong Yin,Liandong Zhu,Xiaowen Shi,Francesco G. Gentili,Yohanes Kristianto Nugroho
Flocculation is one of the promising methods for harvesting microalgae. In this study, a series of grafted cationic chitosan-cyclodextrin composite flocculants (CTS/β-CDs) with different structural properties were prepared from chitosan and cyclodextrin. The results showed that the harvesting efficiency of CTS/β-CD-1 for C. vulgaris reached 99.91%. The chain type of polymeric flocculants with moderate graft chain lengths (L = 10–20) and tighter branched chain density distribution (D = 1.0–1.8) was favorable for C. vulgaris harvesting. The addition of CTS/β-CDs caused the discrete C. vulgaris cells to be flocculated and aggregated, and the reorganization of particles resulted in larger particles after flocculation, improving the dewatering performance of microalgae flocs. CTS/β-CDs had no significant inhibitory effect on the extraction of lipids, proteins and carbohydrates, and did not affect the extraction and quality of fatty acid methyl esters, and the re-cultivation experiments of the harvested water showed that chitosan-based flocculant was able to effectively reduce the cost of microalgae harvesting. Electrostatic interactions and bridging were the main harvesting mechanisms between CTS/β-CD-1 and C vulgaris . E-DLVO modeling suggested that flocculation is mainly a result of electrostatic and acid-base interactions when the distance between particles is small. At higher pH, the harvesting efficiency of CTS/β-CD-1 with C. vulgaris decreased. The study contributes to a better understanding of the structure–activity relationship between the structural characteristics of flocculants and the harvesting performance.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Shanqi Zhou,Zhihua Qiao,Siyuan Ling,Mengru Fu,Yanna Han,Cheng Peng,Wei Zhang,Juying Lei
Polybrominated diphenyl ethers (PBDEs) and their substitutes, novel brominated flame retardants (NBFRs), are ubiquitously present in the aquatic environment of electronic waste (e-waste) dismantling region, leading to their inevitable absorption and accumulation by aquatic organisms , which can be transferred to human via directly aquatic product consumption or through food chain, thereby posing potential health risks. This study focused on fish samples from Guiyu and its surrounding areas, and found the total PBDEs concentrations were 24–7400 ng/g lw (mean: 1800 ng/g lw) and the total NBFRs concentrations were 14 to 2300 ng/g lw (mean: 310 ng/g lw). Significant positive correlations were found among PBDE congeners, among different NBFRs, and between NBFRs and commercial PBDEs that they replace. ΣPBDEs and ΣNBFRs in the intestine were 620–350,000 and 91–81,000 ng/g lw (mean: 83000 and 12,000 ng/g lw, respectively), significantly exceeding those in the gills, where ΣPBDEs and ΣNBFRs were 14–37,000 and 39–45,000 ng/g lw (mean: 9200 and 2400 ng/g lw, respectively). The ΣPBDEs and ΣNBFRs showed no non-carcinogenic risks to the target population through dietary intake. Despite the significantly higher daily intake of decabromodiphenyl ethane (DBDPE) compared to decabromodiphenyl ether (BDE209), the non-carcinogenic risk associated with BDE209 remained higher than that of DBDPE. Our findings can assist researchers in understanding the presence of BFRs in aquatic organisms , inhabiting e-waste dismantling areas, and in evaluating the associated health risks posed to humans through dietary exposure.
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CATALYSIS LETTERS
·
2025
·Vol. 155
·期 4
·1-10
·
IF 2.4
Cao Songshuang,Wu Xiaomei,Ma Baodi,Xu Yi
Aliphatic chiral secondary alcohols are important chiral intermediates widely used in the synthesis of drugs and fine chemicals. The whole cells of recombinant E. coli co-expressing alcohol dehydrogenase and glucose dehydrogenase were used to catalyze the asymmetric reduction of three fatty ketones without the addition of exogenous cofactors. The reaction medium and reaction conditions were systematically studied. As expected, the kinds of co-solvents, the molar ratio of glucose/substrate, temperature, pH and cell amount have important influence on the reaction. Under the optimal condition (glucose at 1.5 times substrate concentration, isopropanol at 2%, PBS (0.1 M, pH 8.0), and 45℃), the cells co-expressing both enzymes efficiently catalyzed the asymmetric reduction of three fatty ketones to the corresponding ( S )-fatty alcohols. The conversion and ee value of the products were both greater than 99% after 8 h reaction at 1 M of substrate concentration, and the space-time yield was between 346 ~ 470 g/(L·d). All the products can be obtained on gram scale. The results indicated that this method has potential application value in the efficient and green synthesis of aliphatic chiral secondary alcohols. Graphical
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Yongniu Zhang,Er-Fang Ren,Tao Wen,Shijun Lyu,Lili Gai,Siyu Chen,Kai Li,Zhong Han,Fuge Niu,Debao Niu
The study aimed to investigate the allergenicity change in casein treated with dielectric barrier discharge (DBD) plasma during in vitro simulated digestion, focusing on the immunoglobulin E (IgE) linear epitopes and utilizing a sensitized-cell model. Results indicated that prior treatment with DBD plasma treatment (4 min) before simulated digestion led to a 10.5% reduction in the IgE-binding capacity of casein digestion products. Moreover, the release of biologically active substances induced from KU812 cells, including β-HEX release rate, human histamine, IL-4, IL-6, and TNF-α, decreased by 2.1, 28.1, 20.6, 11.6, and 17.3%, respectively. Through a combined analysis of LC-MS/MS and immunoinformatics tools, it was revealed that DBD plasma treatment promoted the degradation of the IgE linear epitopes of casein during digestion, particularly those located in the α-helix region of α s1 -CN and α s2 -CN. These findings suggest that DBD plasma treatment prior to digestion may alleviate casein allergic reactions.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Yudong Song,Wuliang Sun,Xinjian Shi,Zhen Qin,Qianqian Wu,Shengyan Yin,Song Liang,Zhenning Liu,Hang Sun
Electronic skin (e-skin) inspired by the sensory function of the skin demonstrates broad application prospects in health, medicine, and human–machine interaction. Herein, we developed a self-powered all-fiber bio-inspired e-skin (AFBI E-skin) that integrated functions of antifouling, antibacterial, biocompatibility and breathability. AFBI E-skin was composed of three layers of electrospun nanofibrous films. The superhydrophobic outer layer Poly(vinylidene fluoride)-silica nanofibrous films (PVDF-SiO 2 NFs) possessed antifouling properties against common liquids in daily life and resisted bacterial adhesion. The polyaniline nanofibrous films (PANI NFs) were used as the electrode layer, and it had strong “static” antibacterial capability. Meanwhile, the inner layer Polylactic acid nanofibrous films (PLA NFs) served as a biocompatible substrate. Based on the triboelectric nanogenerator principle, AFBI E-skin not only enabled self-powered sensing but also utilized the generated electrical stimulation for “dynamic” antibacterial. The “dynamic-static” synergistic antibacterial strategy greatly enhanced the antibacterial effect. AFBI E-skin could be used for self-powered motion monitoring to obtain a stable signal output even when water was splashed on its surface. Finally, based on AFBI E-skin, we constructed an ultra-long-range human-machine interaction control system, enabling synchronized hand gestures between human hand and robotic hand in any internet-covered area worldwide theoretically. AFBI E-skin exhibited vast application potential in fields like smart wearable electronics and intelligent robotics.
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FOOD HYDROCOLLOIDS
·
2024
·
IF 11
Jiayu Zheng,Diandian Wang,Hao Duan,Jinhong Guo,Yue Zheng,Wenhao Li,Wenjie Yan
This study investigated the effects of microwave (MW, 300W, 900W), electron beam irradiation (EBI, 8, 24 KGy), and their combination (MW-EBI, EBI-MW) on the morphology, structure and physicochemical properties of red adzuki bean starch. MW or EBI treatments had little effect on starch morphology, but high-frequency MW and high doses of EBI combined modification resulted in starch granule cracking. Both EBI and MW treatments retained the C-type crystalline structure of the starch but reduced the relative crystallinity, Mw, and short-range ordering. Besides, starch's short chain (A, B 1 ) content, pasting temperature, solubility, and RDS content were significantly increased. In contrast, long chain (B 2 , B 3 ), SDS + RS content, ΔH, SP, and RDS content were decreased considerably after MW and EBI treatments. Furthermore, the effect of MW and EBI combined modification on starch was higher than the single modification, and the MW-EBI modification was more effective than EBI-MW. Therefore, this study provides a green and efficient method to modify starch, which helps to broaden the scope of starch application.
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MICROCHIMICA ACTA
·
2025
·Vol. 192
·期 9
·1-14
·
IF 5.3
Cao Xiaodong,Zhang Chenlu,Gao Yu,Yu Weina,Liu Chao,He Shudong,Sun Hanju,Ye Yongkang
Foodborne pathogens are a leading cause of food safety incidents. Here, we developed a highly sensitive dual-channel biosensor for the parallel electrochemical detection of Salmonella typhimurium ( S. typhimurium ) and Escherichia coli ( E. coli ) O157:H7 using bimetallic metal–organic framework (BMOF)-based signal nanotags. The BMOF-based nanotags were synthesized by functionalizing gold nanoparticle-doped CuZr-MOF with signal DNA sequences sDNA1 (forming sDNA1-AuNPs@CuZr-MOF nanotag) and PbZr-MOF with signal DNA sequence sDNA2 (forming sDNA2-AuNPs@PbZr-MOF nanotag). The biosensing platform was constructed using two glassy carbon electrodes (GCEs). Each GCE was sequentially modified, first with electrodeposited gold nanoparticles (depAu) and then with the corresponding capture DNA sequences (cDNA1 for channel 1 or cDNA2 for channel 2). Target detection was achieved on the sensing interface via sandwich hybridization: in channel 1, the invA gene of S. typhimurium (tDNA1) was recognized by both cDNA1 on the sDNA1-AuNPs@CuZr-MOF nanotag; similarly, in channel 2, the eaeA gene of E. coli O157:H7 (tDNA2) was recognized by both cDNA2 and sDNA2 on the sDNA2-AuNPs@PbZr-MOF nanotag. Leveraging the high stability and ease of surface modification of UiO-66 (Zr-MOF), along with the enhanced electrochemical oxidation signals from the introduced secondary metal ions (Cu 2+ and Pb 2+ ) in Zr-MOF framework, the biosensor achieved parallel detection with wide linear ranges (3.5 to 3.5 × 10 5 CFU mL −1 for S. typhimurium , and 2.2 to 2.2 × 10 5 CFU mL −1 for E. coli O157:H7) and low detection limit (LODs of 0.54 CFU mL −1 and 0.80 CFU mL −1 , respectively). Furthermore, the fabricated biosensor demonstrated excellent reproducibility, selectivity, and stability, highlighting great potential for practical use in monitoring foodborne pathogens. Graphical
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Animals
·
2025
·Vol. 15
·期 23
·3491
·
IF 2.7
Yongjie Zhang,Liyang Guo,Shun Wang,Jie Zhang,Xinlei Ren,Rui Li,Jichang Li,Chunli Chen
Simple SummaryPolymyxin E is widely considered the last resort for treating multidrug-resistant Gram-negative bacteria. However, due to the emergence of the plasmid-mediated MCR-1 resistance gene, an increasing number of strains have developed resistance to polymyxin E. Additionally, the prevalence ofEscherichia coliin chickens has imposed a heavy burden on the global food and poultry farming industries. This study aimed to investigate the in vitro and in vivo synergistic effects and mechanisms of quercetin (QUE) combined with polymyxin E against MCR-1-positiveE. coliJD37 from chickens. The in vitro and in vivo synergistic effects of QUE and polymyxin E were confirmed through in vitro drug sensitivity tests, growth curves, time-kill curves, agar diffusion tests, and in vivo chick infection experiments. The results showed that QUE restored the sensitivity of polymyxin E toE. coliJD37 and restored the sensitivity of polymyxin E toE. coliJD37 mainly by increasing the permeability of the cell membrane, elevating the fluidity of the cell membrane, increasing the membrane potential, and reducing the expression of the AcrAB-TolC efflux pump and Lipopolysaccharide (LPS) regulatory-related genes. Molecular docking results revealed the key binding sites of QUE to MCR-1.In animal husbandry and livestock farming, with the spread of the plasmid-mediated MCR-1 gene, polymyxin E, as the last line of defense against drug-resistant Gram-negative bacteria, is facing severe challenges. This study investigated the in vitro and in vivo synergistic effects and mechanisms of QUE combined with polymyxin E against MCR-1-positive chickenE. coliJD37. In vitro experiments showed that QUE could restore the sensitivity ofE. coliJD37 to polymyxin E (FIC = 0.34375) and enhance the bactericidal effect of polymyxin E by increasing cell membrane permeability, fluidity, and membrane potential, downregulating the expression of the AcrAB-TolC efflux pump and LPS-related genes. Molecular docking further identified the key residues for QUE binding to the MCR-1 protein. The in vivo chick infection model confirmed that combination therapy increased survival rates, reduced bacterial load in tissues, alleviated pathological damage, and decreased levels of intestinal inflammatory factors. Our results demonstrate the synergistic bactericidal effect of the QUE-polymyxin E combination against MCR-1-positiveE. coliand elucidate its underlying mechanism.
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