This study explores the adoption of laser-induced breakdown spectroscopy (LIBS) for the analysis of lateral-flow immunoassays (LFIAs). Gold (Au) nanoparticles are standard biomolecular labels among LFIAs, typically detected via colorimetric means. A wide diversity of lanthanide-complexed polymers (LCPs) are also used as immunoassay labels but are inapt for LFIAs due to lab-bound detection instrumentation. This is the first study to show the capability of LIBS to transition LCPs into the realm of LFIAs, and one of the few to apply LIBS to biomolecular label detection in complete immunoassays. Initially, an in-house LIBS system was optimized to detect an Au standard through a process of line selection across acquisition delay times, followed by determining limit of detection (LOD). The optimized LIBS system was applied to Au-labeled Escherichia coli detection on a commercial LFIA; comparison with colorimetric detection yielded similar LODs (1.03E4 and 8.890E3 CFU/mL respectively). Optimization was repeated with lanthanide standards to determine if they were viable alternatives to Au labels. It was found that europium (Eu) and ytterbium (Yb) may be more favorable biomolecular labels than Au. To test whether Eu-complexed polymers conjugated to antibodies could be used as labels in LFIAs, the conjugates were successfully applied to E. coli detection in a modified commercial LFIA. The results suggest interesting opportunities for creating highly multiplexed LFIAs. Multiplexed, sensitive, portable, and rapid LIBS detection of biomolecules concentrated and labeled on LFIAs is highly relevant for applications like food safety, where in-field food contaminant detection is critical. Graphical abstract.

中文翻译：

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使用侧流分析和激光诱导击穿光谱法检测被金属结合抗体标记的大肠杆菌。

这项研究探索了采用激光诱导击穿光谱法（LIBS）进行侧流免疫分析（LFIA）的分析。金（Au）纳米粒子是LFIA中的标准生物分子标记，通常通过比色方法进行检测。各种各样的镧系元素络合聚合物（LCP）也用作免疫分析标记，但由于实验室绑定的检测仪器，不适用于LFIA。这是第一项显示LIBS将LCP过渡到LFIA领域的能力的研究，并且是在完整的免疫分析中将LIBS应用于生物分子标记检测的少数研究之一。最初，对内部LIBS系统进行了优化，以通过跨采集延迟时间的线路选择过程来检测Au标准，然后确定检测限（LOD）。优化的LIBS系统应用于商业LFIA上Au标记的大肠杆菌检测；与比色检测法进行比较得到的LOD相似（分别为1.03E4和8.890E3 CFU / mL）。用镧系元素标准品重复优化，以确定它们是否可以替代Au标签。发现that（Eu）和（Yb）可能比Au更有利于生物分子标记。为了测试缀合至抗体的Eu络合物聚合物是否可以用作LFIA中的标记，将缀合物成功应用于修饰的商品LFIA中的大肠杆菌检测。结果表明创建高度复用的LFIA的有趣机会。对在LFIA上浓缩和标记的生物分子进行多重，灵敏，便携式和快速LIBS检测对食品安全，现场食品污染物检测至关重要的地方。图形概要。