DiagnosDisk - a highly sensitive point-of-care test for detecting SARS-CoV-2 antigen in saliva

DiagnosDisk - 一种用于检测唾液中 SARS-CoV-2 抗原的高度灵敏的现场检测

• 批准号: 10285991
• 负责人: James Lai
• 金额: $ 23.33万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-25 至 2022-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10285991
• 关键词: 2019-nCoV; Acute; Address; Adopted; Antibodies; Antigens; Biological Assay; Blood Plasma Volume; COVID-19; COVID-19 detection; COVID-19 pandemic; COVID-19 patient; COVID-19 screening; Centers for Disease Control and Prevention (U.S.); Cessation of life; Contact Tracing; Coupling; Data; Deposition; Detection; Development; Devices; Diagnosis; Early Diagnosis; Enzyme-Linked Immunosorbent Assay; Equipment; Evaluation; Exhibits; Goals; Gold; Gold Colloid; Human Resources; Hydrophobicity; Image; Immunoassay; Individual; Infection; Lateral; Location; Malaria; Measures; Membrane; Noise; Nucleocapsid; Patients; Plasma; Polymers; Precipitation; Prostate-Specific Antigen; Proteins; Reagent; Reverse Transcriptase Polymerase Chain Reaction; SARS-CoV-2 antigen; SARS-CoV-2 infection; SARS-CoV-2 negative; SARS-CoV-2 positive; Saliva; Salivary; Sampling; Scanning; Sensitivity and Specificity; Signal Transduction; Specimen; Temperature; Testing; Time; Training; United States; Viral Antigens; Viral Load result; Virus; Visual; acute infection; antibody conjugate; antigen binding; antigen detection; design; detection assay; detection limit; hydrophilicity; improved; innovation; medical attention; novel; pandemic disease; point of care testing; rapid test; saliva sample; salivary assay; sample collection; scale up; screening; success; viral RNA

Project Summary/Abstract SARS-CoV-2, a global pandemic, has caused more than 6 million infections and 180,000 deaths in the United States alone during the past 7 months. Both the WHO and CDC emphasize the need for point-of-care (POC) tests to expand diagnosis of acute infections to control the pandemic (i.e. isolating infected individuals). The current gold standard test for diagnosing acute SARS-CoV-2 infection is reverse transcriptase polymerase chain reaction (RT-PCR) with nasopharyngeal samples. The assay is highly sensitive, but requires well-trained personnel for sample collection and locations with specialized equipment. Therefore, the turnaround time varies from one to few days, delaying isolation, contact tracing, and medical attention. These challenges can be addressed with lateral flow immunoassays (LFIA) to detect viral antigens in self-collected saliva samples. Compared to nasopharyngeal specimens, studies have demonstrated that assays with saliva samples are more consistent and the saliva itself may contain higher viral load. However, existing LFIA for detecting salivary antigens exhibit poor sensitivity (≤ 40%) caused by the use of small sample volumes and sample dilution. To achieve timely and accurate screening of suspected COVID-19 cases, this project aims to develop a rapid assay for detecting SARS-CoV-2 antigens in saliva with high sensitivity to meet WHO's target product profile. We hypothesize that using ≥500 µL saliva as the assay sample can significantly improve the sensitivity because a larger specimen volume provides more analytes for detection. The new test will employ temperature-responsive polymer-antibody conjugates in conjunction with DiagnosDisk, a novel flow-through assay device. The approach is innovative in in using enriched saliva specimens for more consistent assay results, enhancing antigen detection by scaling up the saliva specimen volume, and adopting the well- developed sandwich immunoassay for DiagnosDisk with temperature-responsive polymer reagents that simplify the design while maximizing the sensitivity. We will employ polymer-antibody conjugates that efficiently isolate analytes in saliva (Aim 1) and fabricate the DiagnosDisk device to accommodate larger volume saliva specimens to improve the detection limit (Aim 2). The sensitivity of the new rapid assay, which combines polymer-antibody conjugates and DiagnosDisk, will be evaluated using saliva specimens from COVID-19 positive and negative patients (Aim 3).

项目总结/摘要 SARS-CoV-2是一种全球流行病，在美国已造成600多万人感染，18万人死亡。 在过去的7个月里。世卫组织和疾病预防控制中心都强调需要护理点（POC） 扩大急性感染诊断的检测，以控制大流行（即隔离受感染者）。的 目前诊断急性SARS-CoV-2感染的金标准测试是逆转录酶聚合酶 用鼻咽标本进行RT-PCR检测。该测定法是高度敏感的，但需要训练有素的 负责样品采集的人员和配备专门设备的地点。因此，周转时间 从一天到几天不等，会延迟隔离、接触者追踪和医疗护理。这些挑战可以 用侧流免疫测定法（LFIA）检测自我收集的唾液样本中的病毒抗原。 与鼻咽样本相比，研究表明，唾液样本的检测是 更一致，唾液本身可能含有更高的病毒载量。然而，现有的LFIA用于检测 唾液抗原由于使用小样本体积和样本量而表现出低灵敏度（≤ 40%）， 稀释为了及时准确地筛查疑似COVID-19病例，该项目旨在开发 一种快速检测唾液中SARS-CoV-2抗原的方法，具有高灵敏度，可满足WHO的目标产品 profile.我们假设使用≥500 µL唾液作为检测样本可以显著提高灵敏度 因为更大的样本体积提供更多的分析物用于检测。新测试将采用 温度响应性聚合物-抗体缀合物与诊断盘（一种新型的流通 测定装置。该方法是创新的，在使用丰富的唾液标本更一致的测定 结果，通过按比例增加唾液样本体积来增强抗原检测，并采用良好的 开发了具有温度响应聚合物试剂的诊断盘夹心免疫测定法， 简化设计，同时最大化灵敏度。我们将采用聚合物-抗体缀合物， 分离唾液中的分析物（目标1），并制造DiagnosDisk装置以容纳更大体积的唾液 样品，以提高检测限（目标2）。新的快速检测的灵敏度， 聚合物-抗体偶联物和诊断盘，将使用来自COVID-19的唾液标本进行评估 阳性和阴性患者（目标3）。