组成图示
点击图片查看大图 · 依据论文自动绘制
传感器类型
表面等离子共振(SPR)生物传感器
检测对象
银纳米颗粒（silver nanoparticles，AgNPs）；样品基质：新鲜黄瓜/番茄提取物、河水（Lower Rhine河水）
检测原理
传感器以hMT1A为识别元件，其分子内约20个半胱氨酸巯基可与银纳米颗粒表面结合；单个AgNP可同时结合多个hMT1A，并在CM5水凝胶中形成交联。当样品流经芯片时，AgNPs与hMT1A结合使界面质量增加，引起SPR共振角/响应单位变化。AgNPs的局域表面等离子体还可与金表面表面等离子体极化激元耦合，进一步放大SPR信号。信号随AgNPs浓度呈剂量依赖，用四参数S形曲线拟合得到EC50；较大粒径和未包覆AgNPs因质量更大及LSPR耦合更强而响应更高。银离子也可结合hMT1A，但同质量下响应约为AgNPs的50%。
检测灵敏度
灵敏度: parts per billion (ppb) 级；检测浓度范围: 0.2 μg/L–8.7 mg/L；EC50: 156 μg/L（ES AgNPs）；EC50: 328 μg/L（NC AgNPs）
效应效果
与鸡卵白蛋白（OVA）和IgG相比，hMT1A对AgNPs结合最强，IgG结合约为hMT1A的1/3，OVA几乎无结合。0 mM NaCl下Cd、Zn、Ni交叉反应约40%，Mn、Ca、Mg约20%，Fe<10%；1 mM NaCl下多数降至约15%；10 mM NaCl下Mn、Ca、Mg、Fe不可检出，Cd、Zn、Ni分别为4%、10%、5%。Ag+同质量响应比ES AgNPs低约50%。加标样品中，黄瓜20倍稀释接近100%响应，番茄100倍稀释达缓冲液响应，河水100倍稀释为60%。芯片稳定至少200循环、4个月，10 min内完成检测，适合食品安全与环境监测筛查。
传感器的构成
- 基底/换能器：CM5传感器芯片（carboxymethylated dextran，CM5）/金表面，提供SPR换能
- 活化层：EDC/NHS（0.4 M EDC、0.1 M NHS）活化表面形成活性酯，用于共价偶联
- 识别元件：人金属硫蛋白1A（human metallothionein 1A，hMT1A），通过伯胺固定并结合AgNPs
- 封闭剂：1 M ethanolamine（pH 8.5），封闭剩余活性基团
- 参考通道：blank flow channel，仅EDC/NHS活化并用ethanolamine封闭，用于双参考扣除
- 运行缓冲液：20 mM HEPES（pH 7.4），维持37℃结合条件，可加NaCl调节选择性
- 再生剂：100 mM NaOH，双次注射再生hMT1A表面
中文摘要
银纳米颗粒（AgNPs）因抗菌性能被广泛用于洗衣机、冰箱、服装、医疗器械和食品包装等消费品，但其潜在生物毒性引发健康与环境风险担忧。为建立快速、自动化的纳米银监测方法，本文报道了一种基于人金属硫蛋白1A（hMT1A）的表面等离子共振（SPR）生物传感器。hMT1A通过EDC/NHS化学共价固定于CM5传感器芯片表面，可直接捕获具有生物活性的银纳米颗粒，实现ppb级筛查。与其他蛋白配体相比，hMT1A对AgNPs的结合能力更强。该传感器对不同粒径和表面包覆AgNPs的选择性与灵敏度进行了表征，并应用于新鲜蔬菜和河水等实际样品检测。结果表明，hMT1A-SPR传感器有望作为食品安全与环境监测中银纳米颗粒的常规快速筛查工具。
英文摘要
Silver nanoparticles are recognized as effective antimicrobial agents and have been implemented in various consumer products including washing machines, refrigerators, clothing, medical devices, and food packaging. Alongside the silver nanoparticles benefits, their novel properties have raised concerns about possible adverse effects on biological systems. To protect consumer's health and the environment, efficient monitoring of silver nanoparticles needs to be established. Here, we present the development of human metallothionein (MT) based surface plasmon resonance (SPR) sensor for rapid detection of nanosilver. Incorporation of human metallothionein 1A to the sensor surface enables screening for potentially biologically active silver nanoparticles at parts per billion sensitivity. Other protein ligands were also tested for binding capacity of the nanosilver and were found to be inferior to the metallothionein. The biosensor has been characterized in terms of selectivity and sensitivity towards different types of silver nanoparticles and applied in measurements of real-life samples-such as fresh vegetables and river water. Our findings suggest that human MT1-based SPR sensor has the potential to be utilized as a routine screening method for silver nanoparticles, that can provide rapid and automated analysis dedicated to environmental and food safety monitoring.