Materón Elsa M, Gómez Faustino R, Almeida Mariana B, Shimizu Flavio M, Wong Ademar, Teodoro Kelcilene B R, Silva Filipe S R, Lima Manoel J A, Angelim Monara Kaelle S C, Melendez Matias E, Porras Nelson, Vieira Pedro M, Correa Daniel S, Carrilho Emanuel, Oliveira Osvaldo N, Azevedo Ricardo B, Goncalves Débora
São Carlos Institute of Physics, University of São Paulo, P.O Box 369, 13560-970São Carlos, SP, Brazil.
São Carlos Institute of Chemistry, University of São Paulo, 13566-590São Carlos, SP, Brazil.
ACS Appl Mater Interfaces. 2022 Dec 14;14(49):54527-54538. doi: 10.1021/acsami.2c15407. Epub 2022 Dec 1.
Low-cost, instrument-free colorimetric tests were developed to detect SARS-CoV-2 using plasmonic biosensors with Au nanoparticles functionalized with polyclonal antibodies (f-AuNPs). Intense color changes were noted with the naked eye owing to plasmon coupling when f-AuNPs form clusters on the virus, with high sensitivity and a detection limit of 0.28 PFU mL (PFU stands for plaque-forming units) in human saliva. Plasmon coupling was corroborated with computer simulations using the finite-difference time-domain (FDTD) method. The strategies based on preparing plasmonic biosensors with f-AuNPs are robust to permit SARS-CoV-2 detection via dynamic light scattering and UV-vis spectroscopy without interference from other viruses, such as influenza and dengue viruses. The diagnosis was made with a smartphone app after processing the images collected from the smartphone camera, measuring the concentration of SARS-CoV-2. Both image processing and machine learning algorithms were found to provide COVID-19 diagnosis with 100% accuracy for saliva samples. In subsidiary experiments, we observed that the biosensor could be used to detect the virus in river waters without pretreatment. With fast responses and requiring small sample amounts (only 20 μL), these colorimetric tests can be deployed in any location within the point-of-care diagnosis paradigm for epidemiological control.
开发了低成本、无需仪器的比色测试，以使用带有用多克隆抗体功能化的金纳米颗粒（f-AuNPs）的等离子体生物传感器检测新型冠状病毒。当f-AuNPs在病毒上形成簇时，由于等离子体耦合，肉眼可观察到强烈的颜色变化，在人唾液中的灵敏度高，检测限为0.28 PFU/mL（PFU代表蚀斑形成单位）。使用时域有限差分（FDTD）方法的计算机模拟证实了等离子体耦合。基于用f-AuNPs制备等离子体生物传感器的策略稳健，可通过动态光散射和紫外可见光谱检测新型冠状病毒，不受其他病毒（如流感病毒和登革热病毒）的干扰。在处理从智能手机摄像头收集的图像并测量新型冠状病毒的浓度后，使用智能手机应用程序进行诊断。发现图像处理和机器学习算法对唾液样本进行新冠肺炎诊断的准确率均为100%。在辅助实验中，我们观察到该生物传感器无需预处理即可用于检测河水中的病毒。这些比色测试响应迅速，所需样品量小（仅20 μL），可在即时诊断范式内的任何地点部署，用于流行病学控制。
