Rapid, simple, and cost-effective diagnostics are needed to improve healthcare at the point of care (POC). However, the most widely used POC diagnostic, the lateral flow immunoassay (LFA), is ∼1000-times less sensitive and has a smaller analytical range than laboratory tests, requiring a confirmatory test to establish truly negative results. Here, a rational and systematic strategy is used to design the LFA contrast label (i.e., gold nanoparticles) to improve the analytical sensitivity, analytical detection range, and antigen quantification of LFAs. Specifically, we discovered that the size (30, 60, or 100 nm) of the gold nanoparticles is a main contributor to the LFA analytical performance through both the degree of receptor interaction and the ultimate visual or thermal contrast signals. Using the optimal LFA design, we demonstrated the ability to improve the analytical sensitivity by 256-fold and expand the analytical detection range from 3 log₁₀ to 6 log₁₀ for diagnosing patients with inflammatory conditions by measuring C-reactive protein. This work demonstrates that, with appropriate design of the contrast label, a simple and commonly used diagnostic technology can compete with more expensive state-of-the-art laboratory tests.

中文翻译：

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纳米颗粒设计在确定侧向流动免疫分析性能中的作用

需要快速，简单且经济高效的诊断程序来改善护理点（POC）的医疗保健。但是，最广泛使用的POC诊断方法，即侧向流免疫测定（LFA），灵敏度比实验室测试低约1000倍，并且分析范围更小，需要进行验证性测试才能确定真正的阴性结果。在这里，一种合理而系统的策略用于设计LFA对比标记（即金纳米颗粒），以提高LFA的分析灵敏度，分析检测范围和抗原定量。具体而言，我们发现金纳米颗粒的大小（30、60或100 nm）是通过受体相互作用的程度以及最终的视觉或热对比信号而成为LFA分析性能的主要因素。使用最佳的LFA设计，₁₀至6 log ₁₀用于通过测量C反应蛋白诊断患有炎症的患者。这项工作表明，通过适当设计对比标签，一种简单且常用的诊断技术可以与更昂贵的最新实验室测试相竞争。