Gold immunochromatographic sensor for the rapid detection of twenty-six sulfonamides in foods

A gold immunochromatographic sensor (GICS) was developed for the rapid detection of 26 sulfonamides in honey samples.The sensor was based on a group-specific monoclonal antibody (mAb) that can recognize all 26 sulfonamides.Three haptens (hapten 1 with a thiazole ring,hapten 2 with a benzene ring,and hapten 3 with a straight carbon chain) were used for antigen preparation.With hybridoma technology,a group-specific mAb was screened with a 50％ maximal inhibitory concentration (IC50) against sulfathizole (STZ) and the other 25 analogues ranging from 0.08 to 90.18 ng/mL.Mono-dispersed gold nanoparticles were conjugated with the mAb to develop the lateral immunochromatographic strip.A labeled antibody concentration of 0.1 μg/mL and a coating antigen concentration of 0.2 μg/mL in the test line were chosen for strip preparation.Under optimized conditions,the visual limits of detection (vLOD) for the concentrations of STZ,sulfamethoxazole,sulfamethizole,sulfadiazine,sulfamerazine,sulfadimethoxine,sulfamonomethoxine,sulfameter,sulfamethoxypyridazine,and sulfachloropyridazine were 5,0.25,0.25,10,5,10,25,2.5,5,0.25,and 10 μg/kg,respectively.Scanner analysis in honey samples revealed good performance for detection of the 26 sulfonamides.Commercial honey samples were tested with the sensor and positive results were confirmed with high-performance liquid chromatography.The proposed strip sensor provides a convenient method for the rapid and reliable determination of sulfonamides pollutants in honey samples.     

Gold nanoparticle-based paper sensor for ultrasensitive and multiple detection of 32 (fluoro)quinolones by one monoclonal antibody

For rapid and simultaneous detection of (fluoro)quinolones, a broadly specific monoclonal antibody (mAb) that recognizes 32 (fluoro)quinolone antibiotics was prepared using a mixture of a norfloxacin derivative and a sarfloxacin derivative as the hapten. An immunochromatographic strip based on gold nanoparticles (AuNPs) was then assembled with goat anti-mouse antibody and antigen (sarfloxacin coupled to ovalbumin), used to form the C line and T line, respectively. This antigen competes with the (fluoro)quinolones in a sample incubated with mAbs labeled with AuNPs. The strip can detect 32 (fluoro)quinolones including oxolinic acid, nalidixic acid, miloxacin, pipemidic acid, piromidic acid, rosoxacin, cinoxacin, norfloxacin, pefloxacin, lomfloxacin, enofloxacin, fleroxacin, ciprofloxacin, enrofloxacin, dafloxacin, orbifloxacin, sparfloxacin, gemifloxacin, besifloxacin, balofloxacin, gatifloxacin, moxifloxacin, nadifloxacin, ofloxacin, marbofloxacin, flumequine, pazufloxacin, prulifloxacin, sarafloxacin, difloxacin, trovafloxacin, and tosufloxacin in milk within 10 min with the naked eye. The cut-off values of the strip range from 1 to 100 ng/mL and the limits of detection are 0.1–10 ng/mL. The strip does not cross-react with antibiotics including tetracycline, sulfamethazine, ampicillin, erythromycin, aflatoxin B1, or gentamicin. In short, this immunochromatographic strip is a very useful tool for the primary screening of (fluoro)quinolones in milk.

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Targeting orthotopic gliomas with renal-clearable luminescent gold nanoparticles

A major clinical translational challenge in nanomedicine is the potential of toxicity associated with the uptake and long-term retention of non-degradable nanoparticles (NPs) in major organs.The development of inorganic NPs that undergo renal clearance could potentially resolve this significant biosafety concern.However,it remains unclear whether inorganic NPs that can be excreted by the kidneys remain capable of targeting tumors with poor permeability.Glioblastoma multiforme,the most malignant orthotopic brain tumor,presents a unique challenge for NP delivery because of the blood-brain barrier and robust blood-tumor barrier of reactive microglia and macroglia in the tumor microenvironment.Herein,we used an orthotopic murine glioma model to investigate the passive targeting of glutathione-coated gold nanoparticles (AuNPs) of 3 nm in diameter that undergo renal clearance and 18-nm AuNPs that fail to undergo renal clearance.Remarkably, we report that 3-nm AuNPs were able to target intracranial tumor tissues with higher efficiency (2.3x relative to surrounding non-tumor normal brain tissues) and greater specificity (3.0x)than did the larger AuNPs.Pharmacokinetics studies suggested that the higher glioma targeting ability of the 3-nm AuNPs may be attributed to the longer retention time in circulation.The total accumulation of the 3-nm AuNPs in major organs was significantly less (8.4x) than that of the 18-nm AuNPs.Microscopic imaging of blood vessels and renal-clearable AuNPs showed extravasation of NPs from the leaky blood-tumor barrier into the tumor interstitium.Taken together,our results suggest that the 3-nm AuNPs,characterized by enhanced permeability and retention,are able to target brain tumors and undergo renal clearance.     

一种在硅材料表面组装金纳米颗粒的新方法

以氯金酸、L-半胱氨酸为反应试剂,利用内电流和金硫自组装效应,在硅材料表面组装了较为均一的金纳米颗粒,并利用荧光分析与硅纳米线场效应晶体管对该方法进行了相关验证。结果表明:经氢氟酸处理后的硅材料,在氯金酸和L-半胱氨酸混合溶液中反应3min可在硅表面得到较为均匀、稳定的金纳米颗粒层,其中,氯金酸浓度为0.5mmol/L,氯金酸和L-半胱氨酸浓度比为3∶1。荧光分析表明该方法组装的金颗粒表面已氨基功能化,使得金纳米颗粒修饰的硅材料在应用于生物检测时可直接醛基化修饰蛋白,简化了实验操作。同时,该方法可以在硅纳米线场效应晶体管中特异性组装金纳米颗粒,有力地支持了相关器件在疾病检测方面的应用。     

Label-free electrochemical immunosensor for sensitive detection of kanamycin

A novel label-free electrochemical immunosensor for sensitive detection of kanamycin based on water-soluble graphene sheet (WGS)/prussian blue-chitosan (PB-CTS)/nanoporous gold (NPG) composited film has been reported. PB was selected as an electron transfer mediator, and was modified onto the electrode together with WGS through electrostatic adsorption. Then NPG was immobilized onto the as-prepared film for biomolecules anchoring. The electroactivity of PB was greatly enhanced in the presence of WGS and NPG. It could mainly be ascribed to the fact that the good conductivity of WGS and NPG promoted electron transfer and enhanced the sensitivity. kanamycin antibody, as a model, was immobilized onto the composite film for the detection of kanamycin. Under optimum conditions, the amperometric signal of PB decreased linearly with kanamycin concentration (0.02-14 ng mL⁻¹), a linear calibration plot (y = 1.3817 + 4.7544x, r = 0.9993), resulting in a low limit of detection (6.31 pg mL⁻¹). The novel immunosensor for the detection of kanamycin in real sample with satisfactory results has been proved. In addition, this method would be easily adapted for the detection of other residual antibiotics in animal derived foods.     

广西镇龙山金（银）矿的构造控制特征

本文阐述了广西镇龙山金（银）矿化集中区内主要断裂构造的基本特征,并指出,其中规模较大的,与矿化关系较密切的主要是近ＥＷ向,次为近ＳＮ向断裂,它们组合成线状,交叉状和放射状断裂带,并严格控制着区内岩浆岩、矿化带、矿脉、矿体和“富矿包“的空间展布。这对找矿评价和预测盲矿体都具有实际意义。     

用流体静力学称量法测定黄金饰品中金的含量

本文研究了用流体静力学称量法，通过测定密度计算金饰品中金的含量，该法简单实用，设备投产少，能满足用户日常检定的需要。该法克服了“试金石”法检定黄金的粗糙性，又解决了电子探针在测试过程中，可能对材料成人偏析所造成的误差。     

勘查砂金的最新技术KJ法

本文介绍了朝鲜民主主义人民共和国金策工业大学金致崇教授发明的根据磁场调查勘查砂金的最新技术(简称KJ法)。这项技术是不用钻探和井探,而只用仪器探出砂金的矿体形状、大小、埋深及品位。     

基于光源调制技术的金标试纸条定量分析仪器

基于光电检测原理,研发了一套可用于金标免疫试纸条定量检测的分析仪器。采用绿光发光二极管(LED)作为发射光源,以光电二极管接收试纸条反射光,并通过步进电机带动检测系统扫描试纸条待检区域。系统采用光源信号的调制与接收信号的解调技术,以消除环境干扰噪声。实验结果表明,该仪器检测结果准确,与真实值之间误差<1%;稳定性高,变异系数CV<2%。