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A portable viable Salmonella detection device based on microfluidic chip and recombinase aided amplification

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Chinese Chemical Letters 2023年第2期34卷 268-273页

作者： Wuzhen Qi Siyuan Wang Lei Wang Xinge Xi Shangyi Wu Yanbin Li Ming Liao jianhan lin Key Laboratory of Agricultural Information Acquisition Technology Ministry of Agriculture and Rural AffairsChina Agricultural UniversityBeijing 100083China Department of Biological and Agricultural Engineering University of ArkansasFayetteville 72701United States College of Veterinary medicine South China Agricultural UniversityGuangzhou 510642China

creening of foodborne pathogens is important to prevent contaminated foods from their supply chains.n this study, a portable detection device was developed for rapid, sensitive and simple detection of viable almonella using a finger-actuated microfluidic chip and an improved recombinase aided amplification (RAA) assay. Improved propidium monoazide(PMAxx) was combined with RAA to enable this device to distinguish viable bacteria from dead ones. The modification of PMAxx into dead bacteria, the magnetic xtraction of nucleic acids from viable bacteria and the RAA detection of extracted nucleic acids were performed using the microfluidic chip on its supporting device by finger press-release operations. The fluorescent signal resulting from RAA amplification of the nucleic acids was collected using a USB camera nd analyzed using a self-developed smartphone App to quantitatively determine the bacterial concenration. This device could detect Salmonella typhimurium in spiked chicken meats from 1.3 × 10^(2) CFU/m L o 1.3 × 10^(7) CFU/m L in 2 h with a lower detection limit of 130 CFU/m L, and has shown its potential for on-site detection of foodborne pathogens.

关键词： Finger-actuated microfluidic chip PMAxx Recombinase aid amplification Smartphone App Viable bacterial detection

A lab-on-a-disc platform based on nickel nanowire net and smartphone imaging for rapid and automatic detection of foodborne bacteria

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Chinese Chemical Letters 2022年第4期33卷 2091-2095页

作者： Xiaoting Huo Lei Wang Wuzhen Qi Na Rong Yingjia Liu Siyuan Wang Hong Duan jianhan lin Key Laboratory of Agricultural Information Acquisition Technology Ministry of Agriculture and Rural AffairsChina Agricultural UniversityBeijing 100083China Key Laboratory of Modern Precision Agriculture System Integration Research Ministry of EducationChina Agricultural UniversityBeijing 100083China

Foodborne pathogenic bacteria have been considered as a major risk factor for food safety. It is of great significance to carry out in-field screening of pathogenic bacteria to prevent the outbreaks of foodborne diseases. In this study, a portable lab-on-a-disc platform with a microfluidic disc was developed for rapid and automatic detection of Salmonella typhimurium using a nickel nanowire(Ni NW) net for effective separation of target bacteria, horseradish peroxidase nanoflowers(HRP NFs) for efficient amplification of biological signals, and a self-developed smartphone APP for accurate analysis of colorimetric images. First,the microfluidic disc was preloaded with reagents and samples and centrifuged to form one bacterial sample column, one immune Ni NW column, one HRP NF column, two washing buffer columns and one tetramethylbenzidine(TMB) column, which were separated by air gaps. Then, a rotatable magnetic field was specifically developed to assemble the Ni NWs into a net, which was automatically controlled by a stepped motor to successively pass through the sample column for specific capture of target bacteria, the HRP NF column for specific label of target bacteria, the washing columns for effective removal of sample background and non-specific binding NFs, and the TMB column for colorimetric determination of target bacteria. The color change of TMB from colorless to blue was finally analyzed using the smartphone APP to quantitatively determine the target bacteria. This lab-on-a-disc platform could detect Salmonella typhimurium from 5.6 × 10^(1) CFU/20 μL to 5.6 × 10^(5) CFU/20 μL in 1 h with a lower detection limit of 56 CFU/20 μL. The recovery of target bacteria in spiked chicken samples ranged from 97.5% to 101.8%. This portable platform integrating separation, labeling, washing, catalysis and detection onto a single disc is featured with automatic operation, fast reaction, and small size and has shown its potential for in-field detection of foodborne pathoge

关键词： Lab-on-a-disk platform Nickel nanowire net Horseradish peroxidase nanoflowers Smartphone Bacteria detection

A microfluidic biosensor for rapid detection of Salmonella typhimurium based on magnetic separation,enzymatic catalysis and electrochemical impedance analysis

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Chinese Chemical Letters 2022年第6期33卷 3156-3160页

作者： Yingjia Liu Dong Jiang Siyuan Wang Gaozhe Cai Li Xue Yanbin Li Ming Liao jianhan lin Key Laboratory of Agricultural Information Acquisition Technology Ministry of Agriculture and Rural AffairsChina Agricultural UniversityBeijing 100083China Department of Biological and Agricultural Engineering University of ArkansasFayettevilleAR 72701United States College of Veterinary medicine South China Agricultural UniversityGuangzhou 510642China

Rapid screening of foodborne pathogens is of great significance to ensure food safety.A microfluidic biosensor based on immunomagnetic separation,enzyme catalysis and electrochemical impedance analysis was developed for rapid and sensitive detection of ***,the bacterial sample,the magnetic nanoparticles(MNPs)modified with capture antibodies,and the enzymatic probes modified with detection antibodies and glucose oxidase(GOx)were simultaneously injected into the microfluidic chip,followed by mixing and incubation to form MNP-bacteria-probe sandwich ***,glucose with high impedance was injected into the chip and catalyzed by the GOx on the complexes into hydrogen peroxide with high impedance and gluconic acid with low impedance,which was finally measured using the low-cost interdigitated microelectrode and the electrochemical impedance analyzer to determine the target *** the optimal conditions,this biosensor could quantitatively detect *** at the concentrations from 1.6×10^(2) CFU/m L to 1.6×10^(6) CFU/m L in 1 h with the low detection limit of 73 CFU/m ***,this biosensor was demonstrated with good feasibility for practical applications by detecting the *** spiked chicken meat samples.

关键词： Biosensor Microfluidic chip Electrochemical impedance Interdigitated microelectrode Foodborne bacteria

177Lu-液态金属ROS放疗增敏剂的合成及对小鼠乳腺癌疗效的初步研究

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中华核医学与分子影像杂志 2024年第6期44卷 343-348页

作者：严骏杰宿晨林剑涵王辛宇潘栋辉徐宇平王立振陈重阳杨敏国家卫生健康委员会核医学重点实验室、江苏省分子核医学重点实验室、江苏省原子医学研究所无锡214063

目的:采用177Lu标记超支化聚合物(HG)修饰的液态金属纳米液滴(LMND)@HG,探索其在乳腺癌治疗中的放疗增敏效应。方法:使用超声破碎法制备LMND@HG,再通过合金化作用进行177Lu标记,得到177Lu-LMND@HG,检测其标记率、血浆稳定性和细胞毒性... 详细信息

目的:采用177Lu标记超支化聚合物(HG)修饰的液态金属纳米液滴(LMND)@HG,探索其在乳腺癌治疗中的放疗增敏效应。方法:使用超声破碎法制备LMND@HG,再通过合金化作用进行177Lu标记,得到177Lu-LMND@HG,检测其标记率、血浆稳定性和细胞毒性。构建小鼠乳腺癌移植瘤模型,瘤体注射177Lu-LMND@HG进行肿瘤抑制实验,采用小动物活体光学成像系统观察肿瘤生长情况。使用免疫组织化学与免疫荧光实验对其抑瘤机制进行初步验证。采用单因素方差分析、重复测量方差分析、最小显著差异t检验分析数据。结果:成功采用177Lu标记LMND@HG,标记率95%以上,产物不需后续纯化,且5 d后血浆中放化纯仍>95%。细胞毒性实验显示888 kBq(40 mg/L)177Lu-LMND@HG对4T1细胞具有明显的毒性,细胞存活率[(16.48±7.81)%]明显低于相同剂量177LuCl 3[(85.77±8.87)%;F=77.81,t=11.73,P<0.001]与40 mg/L LMND@HG[(46.53±5.75)%;t=6.20,P<0.001]处理后的细胞存活率。生物分布实验表明,瘤体注射后5 d 177Lu-LMND@HG仍主要分布于肿瘤组织。肿瘤抑制实验结果表明,1.48 MBq 177Lu-LMND@HG较177LuCl 3可明显抑制肿瘤生长[肿瘤体积:(222.66±97.70)与(789.13±245.04)mm 3;F=18.55,t=4.29,P=0.005]。小动物活体光学成像显示,1.48 MBq与3.70 MBq 177Lu-LMND@HG均明显抑制肿瘤生长。免疫荧光与免疫组织化学实验表明177Lu-LMND@HG可造成双链DNA的断裂,同时通过抑制肿瘤细胞增殖能力与血管新生能力达到抑制肿瘤的效果。结论:本研究成功制备了一种新型的177Lu-液态金属基活性氧(ROS)放疗增敏剂,制备方法高效便捷,产物稳定性高、在小鼠乳腺癌移植瘤模型中显示出明显的放疗增敏效果。

关键词：乳腺肿瘤同位素标记镥放射疗法活性氧肿瘤细胞培养的小鼠裸光学成像

Development of automatic and efficient immuno-separator of foodborne pathogenic bacteria using magnetophoresis and magnetic mixing

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International Journal of Agricultural and Biological Engineering 2019年第5期12卷 167-172页

作者： Yuhe Wang Gaozhe Cai Maohua Wang jianhan lin Key Laboratory of Agricultural Information Acquisition Technology(Beijing) Ministry of Agriculture and Rural AffairsChina Agricultural UniversityBeijing 100083China Key Laboratory of Modern Precision Agriculture System Integration Research Ministry of EducationChina Agricultural UniversityBeijing 100083China

In recent years,the outbreaks of foodborne diseases caused by pathogenic bacteria have made considerable economic losses and shown a threat to public *** key to prevent and control these diseases is fast screening of pathogenic bacteria,which is usually performed with three procedures:sample collection,bacteria separation and bacteria *** sample collection,the national standard methods are often *** bacteria detection,currently available methods such as Polymerase Chain Reaction and Enzyme linked Immuno-Sorbent Assay are often *** bacteria separation,traditional methods such as filtration and centrifugation are not capable to specifically separate the target ***,food samples are very complicated and require efficient pretreatment for bacteria separation and concentration to achieve accurate and reliable *** conventional immune magnetic separation method can be used to specifically separate the bacteria,but it still cannot meet the requirements for food sample pretreatment due to very low concentration of target bacteria in ***,this study developed an automatic and efficient immuno-separator of foodborne bacteria based on magnetophoresis and magnetic mixing,and *** O157:H7 was used as research model.A magnetic mixer was applied to facilitate the immunoreaction between the immune magnetic nanoparticles and the target bacteria cells,and a magnetophoretic separation tubing was utilized for magnetophoretic separation of the magnetic *** the optimal mixing time of 20 min and the optimal flow rate of 50μL/min,the separation efficiency of *** O157:H7 could be more than 90%,showing that the developed immuno-separator is promising to be applied for efficient separation of foodborne bacteria and can be easily extended for separation of other biological targets by using their specific antibodies.

关键词： foodborne bacteria immuno-separator bacteria separation magnetophoresis magnetic mixing magnetic nanoparticles

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面向非规范化数据源的动物体温异常识别方法

农业机械学报 2023年第11期54卷 295-305页

作者：刘元杰安雯林建涵王雅春刘刚中国农业大学信息与电气工程学院北京100083 中国农业大学动物科学技术学院北京100091

在动物体温异常识别中,红外测温等方式容易产生系统偏差使得判断结果不可靠。基于深度学习的方法在不同测温设备上的鲁棒性与泛化性能较差,且难以应用于数据量少、随机性强、标准不一致等非规范化的测温场景。因此,本文提出了一种面向... 详细信息

在动物体温异常识别中,红外测温等方式容易产生系统偏差使得判断结果不可靠。基于深度学习的方法在不同测温设备上的鲁棒性与泛化性能较差,且难以应用于数据量少、随机性强、标准不一致等非规范化的测温场景。因此,本文提出了一种面向非规范化数据源的动物体温异常识别方法,通过衡量体温时序数据间的相似度即可完成异常识别。针对常用的相似性度量算法在序列匹配、序列间距度量上效果不佳的问题,提出了一种改进的动态时间规整算法(Improved dynamic time warping,iDTW)。在点间度量方式上,综合欧氏距离和一阶导数,改善了序列过度对齐问题。使用序列交并比表示序列整体特征,提升了序列间距度量效果。针对不等长序列及过长序列的异常检测问题,提出了基于滑动窗口和序列等分的异常检测方法。以较短序列为滑动窗口遍历较长序列得到一组序列间距,根据训练和检测的不同阶段分别选择其中的最小值或最大值作为相似度衡量结果,以解决不等长序列匹配问题。将过长的样本数据序列等分为多个子序列,取子序列的间距和为样本间距,以解决过长序列导致的正常样本间距过大和异常漏检问题。在公开数据集UCR上的实验分析表明,相比于欧氏距离、动态时间规整、一阶导数动态时间规整和权重动态时间规整算法,iDTW算法结合K-近邻分类器得到的分类准确率在10个UCR数据集上分别平均提高6.0、3.0、5.2、2.5个百分点。基于滑动窗口和序列等分的异常检测方法相比于经典异常检测算法,在3种动物体温数据集上的F1值均获得了明显提升。

关键词：动物体温异常检测相似性度量动态时间规整非规范化数据源

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超声速燃烧中的概率密度函数方法研究进展

航空学报 2024年第8期45卷 24-45页

作者：乔竑玮梁剑寒张林孙明波陈玉俏国防科技大学高超声速技术实验室长沙410073

概率密度函数方法能够精确封闭湍流/化学反应相互作用,在湍流燃烧数值模拟中得到了广泛应用。随着高超声速推进技术的不断发展,超燃冲压发动机内的超声速湍流燃烧为概率密度函数方法的应用带来了新的挑战。首先,综述了概率密度函数方法... 详细信息

概率密度函数方法能够精确封闭湍流/化学反应相互作用,在湍流燃烧数值模拟中得到了广泛应用。随着高超声速推进技术的不断发展,超燃冲压发动机内的超声速湍流燃烧为概率密度函数方法的应用带来了新的挑战。首先,综述了概率密度函数方法应用于超声速湍流燃烧的最新进展,概述了概率密度函数方法的基本理论、关键模型和求解框架;其次,介绍了超声速湍流燃烧对概率密度函数方法的理论、模型和数值求解方面的具体挑战和相关研究工作,包括考虑可压缩效应、高速源项模型修正、小尺度混合模型改进等;然后,综述了概率密度函数方法在超声速湍流燃烧中的应用情况;最后,对超声速燃烧中概率密度函数方法的应用前景和发展方向做出了展望。

关键词：概率密度函数方法湍流燃烧超声速燃烧超燃冲压发动机大涡模拟

后缘开槽型超燃冲压发动机凹腔燃烧室及其促燃特性实验研究

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Acta Mechanica Sinica 2024年第1期40卷 74-84页

作者：张林乔玮梁剑寒王翼丁猛杨雷超孙明波 Science and Technology on Scramjet Laboratory National University of Defense TechnologyChangsha 410073China

为了改善传统的二维梯形凹腔在促进混合和燃烧方面的效果,本文提出了一种在凹腔后缘设置开槽的三维凹腔,并在超声速模型燃烧室中进行了研究.在直连式实验台上开展实验,对传统的二维梯形凹腔(基线)和后缘开槽凹腔进行了对比.结果表明,后... 详细信息

为了改善传统的二维梯形凹腔在促进混合和燃烧方面的效果,本文提出了一种在凹腔后缘设置开槽的三维凹腔,并在超声速模型燃烧室中进行了研究.在直连式实验台上开展实验,对传统的二维梯形凹腔(基线)和后缘开槽凹腔进行了对比.结果表明,后缘开槽凹腔增强了沿燃烧室的燃烧。具体而言,凹腔附近的压力在燃料喷注压力较低时增加6.1%,在燃料喷注压力较高时增加12.7%.基于准一维分析,后缘开槽凹腔的燃烧效率提高了20%以上。对于后缘开槽凹腔,燃烧面积和火焰基底位置受喷注压力的影响小于基线情况.与此同时,后缘开槽凹腔的火焰稳定能力较基线构型更优。凹腔交换面积增加、长深比增大以及开槽诱导的横向流动和流向涡可能是增强混合和燃烧的主要原因.

关键词：燃烧面积横向流动超燃冲压发动机火焰稳定准一维凹腔燃烧效率

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环形六孔纳米磁珠分离器设计与试验

农业机械学报 2016年第5期47卷 315-320,335页

作者：刘洪山林杰斯罗锡文莫嘉嗣林建涵焦培荣华南农业大学电子工程学院广州510642 华南农业大学南方农业机械与装备关键技术教育部重点实验室广州510642 华南农业大学工程学院广州510642 华南理工大学机械与汽车工程学院广州510642 中国农业大学教育部现代精细农业系统集成研究重点实验室北京100083 华南农业大学兽医学院广州510642

免疫磁珠分离技术在生物检测中的应用日益广泛,能提供高强度大梯度磁场环境的纳米磁珠分离器是免疫磁珠分离技术中的关键技术之一。设计了一种新颖的环形六孔纳米磁珠分离器,通过瓦状钕铁硼磁块的优化布局和斜壁坡莫合金导磁片设计,实... 详细信息

免疫磁珠分离技术在生物检测中的应用日益广泛,能提供高强度大梯度磁场环境的纳米磁珠分离器是免疫磁珠分离技术中的关键技术之一。设计了一种新颖的环形六孔纳米磁珠分离器,通过瓦状钕铁硼磁块的优化布局和斜壁坡莫合金导磁片设计,实现了在同一台纳米磁珠分离器上形成6个强磁场高梯度分离区域（分离孔）,分离器最高磁场强度达1.44 T,最高磁场梯度达96.3 T/m（体积865.5 cm3,质量4.8 kg）,同一分离器内6个分离孔内磁场分布相同,孔间平均相对偏差在2.0%~3.3%之间。对磁分离孔磁场分布的测试和仿真结果表明：磁珠分离器体积、导磁片材料和导磁片形状等因素对磁珠分离器磁场强度和梯度有不同程度的影响,采用大体积磁块的磁珠分离器比采用小体积磁块的磁珠分离器、采用坡莫合金作为导磁片比采用软铁材料作为导磁片、采用斜壁形状的导磁片比采用直壁形状的导磁片均能实现较大的磁场强度和梯度。该纳米磁珠分离器已成功应用于大肠杆菌和禽流感病毒的免疫磁分离试验研究,并可以根据不同应用需求,组合相关要素以获得理想的免疫磁珠分离器。

关键词：免疫磁分离磁珠分离器磁场分离效率