微流控生物传感器 2012

A bioanalytical platform for simultaneous detection and quantification of biological toxins.

Sensors (Basel, Switzerland) Weingart OG, Gao H, Crevoisier F, Heitger F, Avondet MA, Sigrist H
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组成图示

A bioanalytical platform for simultan... 传感器构成示意图

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传感器类型

微流控生物传感器

检测对象

肉毒神经毒素A(Botulinum Neurotoxin type A, BoNT/A)、金黄色葡萄球菌肠毒素B(Staphylococcal enterotoxin B, SEB)、蓖麻毒素(ricin);样品基质为缓冲液(PBS/TBS)和生奶(raw milk)

检测原理

IncaSlide 微通道内凸起柱上经 OptoDex 光交联共价固定抗毒素捕获抗体,封闭后加入含毒素样品,目标毒素被对应捕获抗体特异性结合;随后加入生物素化检测抗体,与捕获毒素形成夹心复合物;再加入 Cy5 偶联链霉亲和素,通过生物素-链霉亲和素高亲和结合标记复合物。微流控泵驱动循环反向流孵育,提高结合效率。GenePix 荧光扫描仪读取各阵列点 Cy5 荧光强度,相对荧光强度 RFU 与片上 Atto-BSA 荧光校准点比较,实现毒素种类识别和浓度定量。信号强度随毒素浓度增加而增加,无酶促或核酸放大。

检测灵敏度

LOD: 0.5–1 ng·mL−1(缓冲液或生奶);同时检测 LOD: 1 ng·mL−1(PBS);生奶中 BoNT/A LOD: 1 ng·mL−1,ricin LOD: 5 ng·mL−1,SEB LOD: ≥50 ng·mL−1

效应效果

选择性良好:加标毒素提高10倍时,非目标点非特异信号未显著增加,抗体交叉反应极小。PBS中同步检测BoNT/A、SEB、ricin至1 ng·mL−1;缓冲液单毒素可检测至0.5–1 ng·mL−1,37℃提高BoNT/A和ricin信号。生奶中BoNT/A、ricin分别1和5 ng·mL−1,SEB需≥50 ng·mL−1,ricin背景略升,无假阳性/假阴性。流程<90 min,快于ELISA,优于侧流试纸条。平台可同片检测28种分析物(6重复),IncaSlide低成本可弃,IncaTrace可去污,适合食品安全与生物防御。

传感器的构成

  • 基底/反应室:微结构聚合物片 IncaSlide(注塑成型,含 500 µm 微通道与 384 个凸起柱,叠层形成 28 µL 反应室,支撑阵列并作为孵育室)
  • 光交联修饰层:OptoDex 光交联聚合物(涂覆通道,经 UV 350 nm 与捕获抗体共价结合)
  • 识别元件:抗毒素捕获抗体(anti-BoNT/A、anti-SEB、anti-Ricin,印刷于凸起柱上,特异性捕获目标毒素)
  • 封闭剂:Inca Block 6000(封闭非特异结合位点,降低背景)
  • 检测抗体:生物素化检测抗体(biotinylated anti-BoNT/A、anti-SEB、anti-ricin,与捕获毒素形成夹心复合物)
  • 信号标记物:Cy5 偶联链霉亲和素(Cy5-streptavidin,结合生物素化检测抗体,提供统一荧光信号)
  • 流体处理与读出:IncaTrace 仪器(多通道蠕动泵、加热板、管路,循环反向流孵育)与 GenePix Personal 4100 A 荧光扫描仪(图像分析与信号定量)

中文摘要

频发事件表明,由细菌、真菌、植物或动物产生的毒素日益成为食物中毒或中毒事件的重要原因。由于毒性高,部分毒素也被视为潜在生物战剂。因此,对有毒物质的控制、检测和中和给食品安全、医疗和军事生物防御带来沉重经济负担。本文描述了一种新型多功能仪器及相关程序,用于基于阵列同时检测细菌和植物毒素。该生物分析平台将共价固定捕获探针的特异性与专用仪器及基于免疫的微阵列分析相结合。平台由微结构聚合物片组成,该片既作为印刷阵列的支撑,又作为孵育室;还包括一台操作简便的仪器,可在可选检测温度下同时处理多张片。Cy5偶联链霉亲和素作为统一荧光示踪剂。通过荧光图像分析和信号定量,可确定毒素种类和浓度。系统性能通过免疫检测肉毒神经毒素A(BoNT/A)、金黄色葡萄球菌肠毒素B(SEB)和植物毒素蓖麻毒素(ricin)进行了研究。在缓冲液或生奶中,毒素可检测至低至0.5–1 ng·mL−1。

英文摘要

Prevalent incidents support the notion that toxins, produced by bacteria, fungi, plants or animals are increasingly responsible for food poisoning or intoxication. Owing to their high toxicity some toxins are also regarded as potential biological warfare agents. Accordingly, control, detection and neutralization of toxic substances are a considerable economic burden to food safety, health care and military biodefense. The present contribution describes a new versatile instrument and related procedures for array-based simultaneous detection of bacterial and plant toxins using a bioanalytical platform which combines the specificity of covalently immobilized capture probes with a dedicated instrumentation and immuno-based microarray analytics. The bioanalytical platform consists of a microstructured polymer slide serving both as support of printed arrays and as incubation chamber. The platform further includes an easy-to-operate instrument for simultaneous slide processing at selectable assay temperature. Cy5 coupled streptavidin is used as unifying fluorescent tracer. Fluorescence image analysis and signal quantitation allow determination of the toxin's identity and concentration. The system's performance has been investigated by immunological detection of Botulinum Neurotoxin type A (BoNT/A), Staphylococcal enterotoxin B (SEB), and the plant toxin ricin. Toxins were detectable at levels as low as 0.5-1 ng · mL(-1) in buffer or in raw milk.

关键词

生物传感器微流控毒素检测免疫微阵列荧光检测食品安全