CeFe nanofibrous carbon nanozyme integrated with smartphone for the point-of-care testing of norfloxacin in water

The overuse of antibiotics has led to the severe contamination of water bodies,posing a considerable hazard to human health.Therefore,the development of an accurate and rapid point-of-care testing(POCT)platform for the quantitative detection of antibiotics is necessary.In this study,Cerium oxide(CeO_(2))and Ferrosoferric oxide(Fe_(3)O_(4))nanoparticles were simultaneously encapsulated into N-doped nanofibrous carbon microspheres to form of a novel nanozyme(CeFe-NCMzyme)with a porous structure,high surface area,and N-doped carbon material properties,leading to a considerable enhancement of the peroxidase(POD)-like activity compared with that of the CeO_(2)or Fe3O4 nanoparticles alone.The POD-like activity of CeFe-NCMzyme can be quenched using L-Cysteine(Cys)and subsequently restored by the addition of a quinolone antibiotic(norfloxacin,NOR).Therefore,CeFe-NCMzyme was used as a colorimetric sensor to detect NOR via an“On-Off”model of POD-like activity.The sensor possessed a wide linear range of 0.05–20.0μM(R^(2)=0.9910)with a detection limit of 35.70 nM.Furthermore,a smartphone-assisted POCT platform with CeFe-NCMzyme was fabricated for quantitative detection of NOR based on RGB analysis.With the use of the POCT platform,a linear range of 0.1–20.0μM and a detection limit of 54.10 nM were obtained.The spiked recoveries in the water samples were ranged from 97.73%to 102.01%,and the sensor exhibited good accuracy and acceptable reliability.This study provides a portable POCT platform for the on-site and quantitative monitoring of quinolone antibiotics in real samples,particularly in resource-constrained settings.

诺氟沙星(Norfloxacin)对蛋白核小球藻(Chlorella pyrenoidosa)生长及抗氧化酶活性的影响

以蛋白核小球藻(Chlorella pyrenoidosa)为实验材料,研究了喹诺酮类药物诺氟沙星(Norfloxacin,NFLX)对小球藻生长及抗氧化酶活性的影响.结果表明,NFLX对小球藻的96hEC50为30.78mg·L-1,属于低毒.NFLX暴露对小球藻谷胱甘肽硫转移酶(GST)和过氧化氢酶(CAT)具有显著影响,当NFLX浓度高于30mg·L-1时,小球藻GST活性受到显著诱导,并随NFLX浓度增加而显著升高,而小球藻CAT活性随NFLX暴露浓度的升高表现出先诱导后抑制现象.NFLX对谷胱甘肽(GSH)和7-乙氧基-异吩唑酮-脱乙基酶(EROD)的影响较弱.在低浓度NFLX暴露下,GST和CAT可作为NFLX暴露的生物标记物.

基于羧甲基纤维素包裹铜纳米颗粒复合材料电化学传感器检测牛奶中诺氟沙星

以羧甲基纤维素(carboxymethyl cellulose,CMC)包覆的铜纳米颗粒(copper nanoparticles,Cu NPs)和碳黑(carbon black,CB)为原料,制备CMC@Cu/CB复合材料,构建检测诺氟沙星(norfloxacin,NFX)的高灵敏度电化学传感器。基于扫描电子显微镜、X射线光电子能谱和X射线衍射等手段对CMC@Cu/CB结构和形貌进行表征,在玻碳电极(glassy carbon electrode,GCE)表面滴铸复合材料悬浮液,制备CMC@Cu/CB/GCE传感器。结果表明:CMC@Cu/CB/GCE呈均匀分散球状,传感器对NFX具有良好的电流响应,线性范围为0.4~100.0μmol/L,检出限为0.24μmol/L(R_(SN)=3),此外,该修饰电极对实际样品中NFX的测定具有良好的灵敏度和稳定性,对牛奶提取物中NFX的加标回收率为98.8%~112.5%。同时,由于实验过程中原材料价格低廉,传感器的制备成本极低,在实际检测中具有良好的应用前景。

胶体金免疫层析法快速检测动物源食品中的诺氟沙星

胶体金免疫层析法具有高特异性、高灵敏度、高重复性等特点,能够准确地检测出样品中的目标物,在快速检测领域具有广泛应用。本研究将胶体金免疫层析法用于快速检测动物源食品(猪肉、鸡肉、鱼肉、虾肉、鸡蛋)中的诺氟沙星(Norfloxacin,NOR)残留,对方法进行验证,相对准确度为97.0%。方法的检出限为2μg/kg,检测性能强。在上述5种不同基质样品中,NOR胶体金快速检测方法的灵敏度为99%、特异度为98%、假阳性率为2%、假阴性率为1%。该方法简单快速、灵敏准确,适于复杂基质中NOR的快速精准检测。

Impacts of soil organic matter, pH and exogenous copper on sorption behavior of norfloxacin in three soils

Norfloxacin sorption and the factors （soil organic matter （SOM）, pH, and exogenous copper （Cu） influencing the sorption were investigated in a black soil （soil B）, a fluvo-aquic soil （soil F）, and a red soil （soil R）. With increasing norfloxacin concentrations, sorption amount of norfloxacin increased in both the bulk soils and their SOM-removed soils, but the sorption capacity of SOM-removed soils was higher than that of their corresponding bulk soils, indicating that the process of norfloxacin sorption in soil was influenced by the soil properties including SOM. The sorption data in all bulk soils and SOM-removed soils were fitted to Freundlich and Langmuir models. The correlation coefficients suggested that the experimental data fitted better to Freundlich equation than to Langmuir equation. Furthermore, the data from soil F and SOM-removed F could not be described by Langmuir equation. The norfloxacin sorption amount decreased in soil B and soil F, whereas it increased in soil R as solution pH increased. The maximum KD and Koc were achieved in soil R when the equilibrium solution pH was 6. The norfloxacin sorption was also influenced by the exogenous Cu^2＋, which depended on the soil types and Cu^2＋ concentrations. With increasing Cu^2＋ concentrations in solution, generally, sorption amount, KD and Koc for norfloxacin in soils increased and were up to a peak at 100 mg/L Cu^2＋, and then the sorption amount decreased regardless of norfloxacin levels.

Synthesis,Crystal Structure and Antitumor Activity of Mixed Ligand Coordination Compound of Copper with Norfloxacin and 1,10-Phen,[Cu(NFLX)(phen)(H2O)]NO3·3H2O

The mixed ligand coordination compound of copper with norfloxacin (NFLX) and 1, 10-phen has been synthesized and characterized by means of X-ray single crystal diffraction. The structure features of the coordination compound are described. Antibacterial activities of the coordination compound have been tested against different microorganisms. The antitumor activities of the coordination compound on leukemia HL-60 cell line and liver cancer BEL-7402 cell line have been measured, respectively. The results indicated that the coordination compound has strong inhibitory effect on HL-60 and BEL-7402 cell lines.

Enhancement of norfloxacin solubility via inclusion complexation with β-cyclodextrin and its derivative hydroxypropyl-β-cyclodextrin

The objectives of the study were to investigate the effects of β-cyclodextrin(βCD) and hydroxypropyl-β-cyclodextrin(HPβCD) on the solubility and dissolution rate of norfloxacin prepared using three different methods, at drug to cyclodextrin weight ratios of 1:1, 1:2, 1:4 and 1:8. All the methods increased the solubility and dissolution rate of norfloxacin via inclusion complexation with βCD and HPβCD. Norfloxacin was converted from crystalline to amorphous form through inclusion complexation. Solvent evaporation method was the most effective method in terms of norfloxacin solubilisation, while inclusion complex of HPβCD has higher solubility than βCD complex when prepared using the same procedure.

Exploring a broadened operating pH range for norfloxacin removal via simulated solar-light-mediated Bi_2WO_6 process

Semiconductor photocatalysis can be operated over a narrow pH range for wastewater treatment. In this study, a simulated solar-light-mediated bismuth tungstate (SSL/Bi2WO6) process is found to be effective for norfloxacin degradation over a narrow pH range. To broaden the operating pH range of the SSL/Bi2WO6 process, an NH4+ buffer system and an Fe3+ salt were introduced under extremely basic and acidic pH conditions, respectively. The NH4+ buffer system continuously supplied hydroxyl ions to generate ·OH radicals and prevented acidification of the solution, resulting in improved norfloxacin removal and mineralization removal under alkaline conditions. In contrast, the Fe3+ salt offered an additional homogeneous photo-sensitization pathway. The former treatment assisted in norfloxacin decay and the latter increased the collision frequency between the photo-generated hole and hydroxyl ions. Moreover, the effect of parameters such as pH and Fe3+ dosage was optimized.

Effect of bismuth tungstate with different hierarchical architectures on photocatalytic degradation of norfloxacin under visible light

The photocatalytic degradation of norfloxacin by bismuth tungstate(Bi2WO6)with different hierarchical architectures wasinvestigated under visible light irradiation.Bi2WO6was prepared by hydrothermal method with the reaction solution pH rangingfrom4to11.The relatively ultrathin Bi2WO6nanoflakes prepared at pH4showed excellent adsorption and photodegradationefficiency towards norfloxacin.The characterization results showed that Bi2WO6prepared at pH4had a larger specific area andfaster photo-generated carrier separation rate.The decay rate reached the maximum in weak alkaline reaction solution,which couldbe attributed to the presence of moderate OH-anions.The present study demonstrated that the smaller size of Bi2WO6could be anefficient photocatalyst on the degradation of norfloxacin in the aquatic environment.

Crystal Structure of Norfloxacin Methanol Solvate: C_(16)H_(18)FN_3O_3·CH_3OH·H_2O

Norfloxacin methanol solvate （ 1 -ethyl-6-fluoro- 1,4-dihydro-4-oxo-7-（ 1 -piperazinyl）-3- quinoline carboxylic acid methanol solvate） has been prepared. The crystal and molecular structures of the title compound, C16H18FN3O3·CH3OH·H2O, were determined by X-ray diffraction method. The compound crystallizes in monoclinic, space group P21/c with a = 7.8660（16）, b = 22.525 （5）, c = 10.253（2）A, β= 108.31°, Mr = 369.39, V = 1724.7（6）A^3, Z = 4, Dc= 1.423 g/cm^3, F（000） = 784, R = 0.0557 and wR = 0.1224. The TGA analysis indicates that it decomposes completely at 723.75℃.

Adsorption and degradation of norfloxacin by a novel molecular imprinting magnetic Fenton-like catalyst

In this study,a novel magnetically separable adsorbent,molecular imprinting magnetic γ-Fe_2O_3/crosslinked chitosan composites(MIPs),were prepared by a microemulsion process.Adsorption and Fenton-like oxidative degradation of a model pharmaceutical pollutant norfloxacin(NOR) by using MIPs were investigated.Various characterization methods were used to study the properties of MIPs,and it is suggested that the hydroxyl groups are the main adsorption sites for NOR.MIPs present better selective adsorption for NOR than its reference antibiotic sulfadiazine.The NOR adsorption data can be well fitted by Langmuir isotherm model and pseudosecond-order kinetic model.The optimum pH range for NOR adsorption is 7-10.In addition,the MIP-catalyzed Fenton-like system(MIPs/H_2O_2) exhibits remarkably faster removal rate for NOR than the case of γ-Fe_2O_3/H_2O_2.The result indicates that MIPs will be a good functional material in decontamination of pharmaceutical wastewaters since MIPs can be magnetically recycled after the treatment.

Minor Groove Binding between Norfloxacin and DNA Duplexes in Solution: A Molecular Dynamics Study

Molecular dynamics were used to investigate the interaction between norfloxacin and DNA duplex. The results showed that norfloxacin was situated in the minor groove of DNA, binding to the TCGA region of d [ATATCGATAT] 2- Specific hydrogen bonds were formed between norfloxacin and guanine base of DNA during the 2 ns MD, which may be the reason for the preferentiality of quinolone antibacterial towards the guanine base of DNA duplex.

Molecularly Imprinted Polymers with Bi-functional Monomers of Polymerizable Cyclodextrin Derivatives and 2-(Diethylamino)-ethyl Methacrylate for Recognition of Norfloxacin in Aqueous Media

A molecularly imprinted polymer was synthesized using 2-（diethylamino）ethylmethacry -late（DEM） and bismethacryloyl-β-cyclodextrin（BMA-β-CD） as bi-functional monomers and norfloxacin（NOF） as a template. The results of equilibrium binding experiments indicated that the polymer has affinity and specificity for NOF in aqueous media, and that its selective recognition ability for the template was higher than that of the imprinted polymers synthesized with a single functional monomer （BMA-β-CD or DEM）.

Thermal Decomposition Kinetics of Ni(Ⅱ)Complex with Norfloxacin

The thermal decomposition of the 2H2O (NFA=C16H18FN3O3, norfloxacin) and its kinetics were studied under the nonisothermal condition in nitrogen by TGDTG and DTA methods. The intermediate and residue for each decomposition were identified from TG curve. The Achar method and the MadhusudananKrishnanNinan (MKN) method were used to analyze the nonisothermal kinetic data. The possible reaction mechanisms were investigated by comparing the kinetic parameters. The kinetic equation for the third stage and the mathematical expressions for the kinetic compensation effects of the third stage were obtained.

Effects of Norfloxacin on the Superoxide Dismutase Activities of 2 Sturgeon Species

[Objective]This study was to investigate the effect of different concentrations of Norfloxacin on the superoxide dismutase （ SOD） activities in the blood plasma and liver tissues of Amur sturgeon （ Acipenser schrencki Brandt） and sterlet （ Acipenser ruthenus Linnaeus） . [Method] Using pharmaco-toxicological evaluation method,Norfloxacin with the concentrations of 0,20,40,60,80 and 100 mg /kg,was orally delivered to the Amur sturgeon and sterlet for 5 d,respectively. The SOD activities in the blood plasma and liver tissues were measured after drug withdrawal for 2 d to explore the optimal dosing concentration of Norfloxacin during sturgeon culture,as well as the effect of Norfloxacin on liver injury. [Result] SOD existed in both two sturgeons but with different amounts,and the SOD activities were higher in the livers than in the blood plasma no matter in the control and all drug delivered groups. Under different drug delivery concentrations,the SOD activities first increased and then decreased in the 2 tissues of the 2 sturgeon species,and the SOD activities reached the maximum when the drug delivery concentration was 40 mg /kg. The drug de- livery concentration had little effect on the SOD activities in the blood plasma,which showed stable changes. When the drug delivery concentration was 40 mg /kg,the SOD activities in the blood plasma of Amur sturgeon were higher than that of sterlet,while for the other concentrations,the SOD activities in the plasma of sterlet showed higher performance. However,the SOD activities changed significantly through drug delivery in the liver tis- sues,and the SOD activities were higher in the sterlet than in the Amur sturgeon when the drug delivery concentrations were 0,40 and 100 mg /kg. The SOD activity in the sterlet was the highest under 40 mg /kg,presenting a sharp peak value. The optimal drug delivery concentration of Norfloxa- cin was 30 -50 mg /kg,under which the Norfloxacin presented best effect and had no injury effect on livers. [Conclusion]This study provides theo- retical basis for the reasonable application of Norfloxacin in aquaculture.

Enhanced adsorption of target branched compounds including antibiotic norfloxacin frameworks on mild steel surface for efficient protection: An experimental and molecular modelling study

In this study, an approach was proposed to employ new target branched compounds(TBCs) including multiple antibiotic norfloxacin frameworks for intensified adsorption films to achieve super protection of mild steel in HCl medium. Thus, the TBCs containing bis/tri norfloxacin skeletons were synthesized by multi-step preparation route. In addition, the reference linear compound(RLC) including a single norfloxacin part was also synthesized. The chemical structures of these compounds were confirmed by various means. It was demonstrated that the TBCs could form the tough adsorption films on the surface of mild steel, which could be processed mainly through chemisorption effect. The electrochemical analysis suggested that the TBCs displayed superior corrosion inhibition performance for low carbon steel in1.0 mol·L^(-1) HCl solution over the RLC(RLC, 87.80%;TBC1, 97.63%;TBC2, 98.35%), which was further understood by the molecular modelling. The isotherm adsorption plots were employed to analyze the spontaneous adsorption process of the TBCs on low carbon steel surface, and a prominent chemisorption could be inferred by the standard Gibbs free energy changes of the adsorption.

探讨金属离子Norfloxacin缩环反应收率的影响

作者通过一系列实验证实了原料中锌离子含量的高低直接影响缩环收率。

铁基双金属催化剂活化过硫酸单盐(PMS)去除诺氟沙星性能研究

采用过渡金属Cu、Co和Mn对纳米零价铁(nZVI)掺杂改性,制备铁基双金属nZVI/Cu、nZVI/Co和nZVI/Mn催化剂,用于活化过氧单硫酸盐(PMS),研究了不同过渡金属、催化体系和过渡金属掺杂量对催化降解诺氟沙星(NOR)性能的影响。结果表明,当Co的掺杂量为5%时,nZVI/Co-5%/PMS活化体系在120 min内实现了84.4%的NOR去除。优异的活化降解性能主要得益于过渡金属Co的引入抑制了nZVI的钝化和团聚。

诺氟沙星对刺参肠道菌群结构与功能特征的影响

近年来,诺氟沙星(norfloxacin,NOR)在水环境中被广泛检出。为探究NOR对棘皮动物的毒性效应,选取刺参(Apostichopus japonicus)为研究对象,将其暴露于0 mg·L^(-1)、1.5×10^(-1) mg·L^(-1)和150 mg·L^(-1)浓度诺氟沙星中56 d,研究NOR暴露对刺参肠道菌群结构及功能的影响。结果显示:刺参肠道核心菌群为变形菌门(Proteobacteria)和疣微菌门(Verrucomicrobia)。与对照组相比,随着环境中NOR暴露浓度的增加,刺参肠道菌群逐渐被罗尔斯通氏菌(Ralstonia)取代,150 mg·L^(-1) NOR处理组罗尔斯通氏菌相对丰度占比高达79.82%,呈现出肠道菌群单一化的现象。基于京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)代谢通路数据库注释,NOR暴露组肠道菌群mRNA翻译、蛋白质复制合成及修复、多糖合成及代谢通路丰度显著上调(P<0.05),而膜运输、氨基酸代谢通路丰度显著下调(P<0.05)。综上可知,水体中NOR影响了刺参肠道菌群结构与功能。本研究旨为水体抗生素生态风险评估提供一定的理论依据。

ZnCl_(2)改性海藻基生物炭去除水体中诺氟沙星的性能及循环利用性研究

过硫酸盐高级氧化工艺(PS-AOPs)因具有氧化能力强、选择性高等优点在抗生素废水处理方面具有广阔的应用前景。选取羊栖菜为研究对象,采用氯化锌(ZnCl_(2))共热裂解法,制备了ZnCl_(2)改性羊栖菜生物炭(YQZn),并将其作为催化剂活化过二硫酸盐(PDS),降解水体中的诺氟沙星(NOR)。结果显示,不同的ZnCl_(2)添加量对生物炭催化活性的影响不同,当ZnCl_(2)与羊栖菜的质量比为1∶1时,催化活性最佳。采用扫描电镜(SEM)、Brunauer-Emmet-Teller(BET)方法、X射线衍射(XRD)分析等表征YQZn的理化性质,探究了ZnCl_(2)的改性机理,同时研究了不同反应条件对YQZn催化活性的影响。结果表明,在PDS浓度为1 mmol·L^(-1)、改性生物炭添加量为0.3 g·L^(-1)、pH为9、NOR浓度为10 mg·L^(-1)的条件下,NOR的去除率最高,可达95.09%。自由基淬灭实验结果表明,SO_(4)^(·-)和HO∙自由基在氧化作用中占主导地位,^(1)O_(2)的作用较为有限。针对粉末生物炭回收困难的问题,将YQZn负载至多孔地质聚合物上,制备了复合物GB。重复利用性实验表明,GB具有良好的降解活性和优良的重复利用性,可有效去除96.68%的NOR。