Abstract

Lateral flow immunoassay (LFIA) is the most widely used platform of the point-of-care (POC) detection. Since the most important factor in deciding the results of this technique is the visual quality of the test, it should be at its optimum. To address this issue, the present study examines optimising critical parameters to improve the quality of LFIA performance. In this regard the penicillin-binding protein 2a (PBP2a) in methicillin-resistant staphylococcus aureus (MRSA) was selected as a bacterial model. The targeted parameters included a) size of gold nanoparticles (AuNP), b) antibody conjugation conditions with AuNP, c) antibody concentrations in the capturing zones, d) the effects of blocking substances and different chemical buffers for pre-treatment of the strips. Visual quality of different manufactured strips revealed that the diameter of 14 ± 2, PH = 9.5 was the optimum for improvement of MRSA detection quality. The optimum concentration of labelling antibody in conjugate pad and concentration of the capturing antibody in the test band were 40 µg/ml and 1.1 µg/μl in PBS buffer (pH 7.4) respectively. In conclusion by finding the critical factors affecting the detection limit of lateral flow and optimising them, the visual quality of LFIA results can be increased.

摘要

横向流动免疫分析（LFIA）是即时诊断（POC）检测最广泛使用的平台。由于决定该技术结果的最重要因素是测试的视觉质量，因此应使其处于最佳状态。为了解决这个问题，本研究检查了优化关键参数以提高LFIA性能的质量。在这方面，耐甲氧西林金黄色葡萄球菌中的青霉素结合蛋白2a（PBP2a）（MRSA）被选为细菌模型。目标参数包括：a）金纳米颗粒（AuNP）的大小，b）抗体与AuNP的结合条件，c）捕获区中的抗体浓度，d）封闭物质和不同化学缓冲液的预处理效果。不同制造试纸条的视觉质量显示，直径14±2，PH = 9.5是提高MRSA检测质量的最佳方法。在PBS缓冲液（pH 7.4）中，缀合物垫中标记抗体的最佳浓度和测试条带中捕获抗体的最佳浓度分别为40 µg / ml和1.1 µg /μl。总之，通过发现影响横向流检测极限的关键因素并对其进行优化，可以提高LFIA结果的视觉质量。