The lateral flow immunoassay test (LFT), as a method of a point of care test, is widely used in disease diagnosis, food security, and environment observation due to its portability and testing rapidity. A fluorescence lateral flow immunoassay was developed recently to enhance the sensitivity and accuracy of the LFT. However, for most fluorescence reporters, their emission and excitation wavelengths are located in the ultraviolet or visible region. Serum or whole blood significantly absorbs and scatters light of this region, and this will result in background signal interference. In this study, we replace traditional fluorescence reporters with near-infrared lanthanide-doped nanoparticles (NIR-RENPs) to establish a NIR-LFT platform. Blood and other biological samples scatter and absorb less near-infrared light than visible light, and the autofluorescence of biological samples is rarely located in this region. Therefore, using NIR light as a signal can diminish the interference of background noise and suffer from less signal attenuation. In addition, compared with commonly used NIR organic dye, NIR-RENPs have better stability. It is promising that lateral flow immunoassays based on NIR lanthanide-doped nanoparticles are able to acquire a lower detection limit and better accuracy, and they are more suitable for application in commercial settings.

中文翻译：

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低干扰横向流动免疫测定测试的近红外掺杂镧系元素的纳米粒子。

侧向流动免疫分析测试（LFT）作为即时检验的一种方法，由于其便携性和测试快速性而广泛用于疾病诊断，食品安全和环境观察。最近开发了一种荧光侧流免疫测定法，以增强LFT的灵敏度和准确性。但是，对于大多数荧光报告分子而言，它们的发射和激发波长位于紫外线或可见光区域。血清或全血会大量吸收和散射该区域的光，这将导致背景信号干扰。在这项研究中，我们用掺有近红外镧系元素的纳米粒子（NIR-RENPs）代替了传统的荧光报告分子，从而建立了NIR-LFT平台。血液和其他生物样本比可见光散射和吸收的近红外光更少，生物样品的自发荧光很少位于该区域。因此，使用近红外光作为信号可以减少背景噪声的干扰，并减少信号衰减。此外，与常用的NIR有机染料相比，NIR-RENP具有更好的稳定性。很有希望的是，基于NIR镧系元素掺杂的纳米粒子的侧向流免疫测定能够获得更低的检测限和更好的准确性，并且它们更适合在商业环境中应用。