Department of Biotechnology, University of Turku, Kiinamyllynkatu 10, Turku 20520, Finland.
Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, Haryana, India.
Anal Chem. 2020 Dec 15;92(24):15766-15772. doi: 10.1021/acs.analchem.0c02748. Epub 2020 Nov 23.
malaria is widespread in the tropical and subtropical regions of the world. There is ongoing effort to eliminate malaria from endemic regions, and sensitive point-of-care (POC) diagnostic tests are required to support this effort. However, current POC tests are not sufficiently sensitive to detect in asymptomatic individuals. After extensive optimization, we have developed a highly sensitive and robust POC test for the detection of infection. The test is based on upconverting nanophosphor-based lateral flow (UCNP-LF) immunoassay. The developed UCNP-LF test was validated using whole blood reference panels containing samples at different parasite densities covering eight strains of from different geographical areas. The limit of detection was compared to a WHO-prequalified rapid diagnostic test (RDT). The UCNP-LF achieved a detection limit of 0.2-2 parasites/μL, depending on the strain, which is 50- to 250-fold improvement in analytical sensitivity over the conventional RDTs. The developed UCNP-LF is highly stable even at 40 °C for at least 5 months. The extensively optimized UCNP-LF assay is as simple as the conventional malaria RDTs and requires 5 μL of whole blood as sample. Results can be read after 20 min from sample addition, with a simple photoluminescence reader. In the absence of a reader device at the testing site, the strips after running the test can be transported and read at a central location with access to a reader. We have found that the test and control line signals are stable for at least 10 months after running the test. The UCNP-LF has potential for diagnostic testing of both symptomatic and asymptomatic individuals.
疟疾广泛分布于世界热带和亚热带地区。目前正在努力消除流行地区的疟疾，因此需要灵敏的即时护理（POC）诊断检测方法来支持这一努力。然而，现有的 POC 检测方法还不够灵敏，无法检测无症状个体中的疟原虫。经过广泛的优化，我们开发了一种用于检测疟原虫感染的高灵敏度和强稳健性的 POC 检测方法。该检测方法基于上转换纳米荧光剂（UCNP）侧向流动（LF）免疫测定。该方法采用包含不同寄生虫密度的全血参考面板进行验证，涵盖了来自不同地理区域的 8 株疟原虫。将检测限与世界卫生组织（WHO）预认证的快速诊断检测（RDT）进行了比较。UCNP-LF 的检测限为 0.2-2 个寄生虫/μL，具体取决于菌株，与传统的 RDT 相比，其分析灵敏度提高了 50-250 倍。即使在 40°C 下，UCNP-LF 也具有高度稳定性，至少可稳定 5 个月。经过广泛优化的 UCNP-LF 检测方法与传统的疟疾 RDT 一样简单，仅需 5μL 全血作为样本。从加入样本后 20 分钟即可读取结果，使用简单的光致发光阅读器。如果在检测现场没有阅读器设备，也可以在测试后将条带运送到具有阅读器的中央位置进行读取。我们发现，即使在运行测试后 10 个月，测试线和控制线的信号仍然稳定。UCNP-LF 具有对有症状和无症状个体进行诊断检测的潜力。
