Colorimetric Lateral Flow Assay Using Unique Hollow Nanoparticles as Labels

试纸检测是一种可在家中或床旁进行的检测技术。在家里COVID-19抗原测试是这种类型的测试的一个例子，也被称为比色侧流测定（CLFA）。CLFA可以在实验室外使用，由非技术人员进行，并且可以用人眼读取结果，而不需要任何设备。尽管CLFA简单，但与其他基于设备的诊断技术相比，其检测灵敏度相对较低。该项目的目标是通过开发一种独特类型的纳米颗粒，大幅提高CLFA技术的灵敏度，同时保持其简单性。该项目将吸引高中生、本科生和研究生参与研究。 活动包括指导本科生的研究经验，通过“高中暑期研究实习”计划为高中生提供研究经验，以及实施新课程“生物材料的化学合成”。比色侧流分析（CLFA）是少数几种可以在实验室外使用而不需要熟练人员和设备的诊断技术之一。目前CLFA发展的瓶颈是其相对较低的检测灵敏度，这是由于来自比色标记的微弱颜色信号。几十年来，金纳米颗粒（AuNPs）已被广泛用作CLFA的比色标记，因为它们具有良好的物理化学性质，包括由于其等离子体活性而显示出特征性的红色。尽管如此，它仍然是一个挑战，以充分提高红色的强度，从而检测灵敏度的金纳米粒子为基础的CLFA。该项目旨在通过开发可用作AuNP替代品的Au/Ag（金/银）合金化中空纳米颗粒（Au/Ag HNP）来突破CLFA的检测限屏障。与传统的金纳米粒子相比，Au/Ag纳米粒子具有更强的等离子体激元活性。此外，由于内部中空，它们具有较低的密度，这有助于CLFA测试条中颗粒的平滑迁移。Au/Ag HNP的这些独特特征使它们成为CLFA的敏感标记，可以显著提高测定的能力，而不影响其简单性。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

Test strip assay is an accessible in-home or point-of-care testing technology. At-home COVID-19 antigen tests are one example of this type of testing, which is also called colorimetric lateral flow assay (CLFA). CLFA can be used outside the laboratory, performed by a non-skilled person, and results can be read with the human eye, without the need of any equipment. Despite the simplicity of CLFA, its detection sensitivity is relatively low compared to other equipment-based diagnostic technologies. The goal of this project is to substantially improve the sensitivity of CLFA technology while retaining its simplicity through the development of a unique type of nanoparticle. This project will engage high school, undergraduate and graduate students in research. Activities include mentored research experiences for undergraduate students, research experiences for high school students through the “Highschool Summer Research Internship” program, and the implementation of a new course “Chemical Synthesis of Biomaterials.”Colorimetric lateral flow assay (CLFA) is one of a handful of diagnostic techniques that can be used outside the laboratory without requiring skilled personnel and equipment. The current bottleneck for CLFA development is its relatively low detection sensitivity due to the weak color signals from colorimetric labels. For decades, gold nanoparticles (AuNPs) have been extensively used as colorimetric labels for CLFA because of their good physicochemical properties, including the display of a characteristic red color due to their plasmonic activities. Nevertheless, it remains a challenge to substantially enhance the intensity of the red color and thus the detection sensitivity of AuNPs-based CLFAs. This project aims to break through the detection limit barrier of CLFA by developing Au/Ag (gold/silver) alloyed hollow nanoparticles (Au/Ag HNPs) that can be used as alternatives to AuNPs. Compared to conventional AuNPs, the Au/Ag HNPs possess much stronger plasmonic activities. In addition, they have lower densities because of the hollow interiors, which facilitates smooth migration of particles in CLFA test strip. These distinct features of Au/Ag HNPs enable them to be sensitive labels for CLFA that can significantly advance the power of the assay without compromising its simplicity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.