Health Unit, Flemish Institute for Technological Research (VITO), Boeretang 200, Mol 2400, Belgium.
Dynamic Bioimaging Lab, Biomedical Research Institute, Hasselt University, Agoralaan C, Diepenbeek 3590, Belgium.
ACS Appl Mater Interfaces. 2024 Jun 12;16(23):30556-30566. doi: 10.1021/acsami.4c04018. Epub 2024 May 28.
Mannose-binding lectin (MBL) activates the complement system lectin pathway and subsequent inflammatory mechanisms. The incidence and outcome of many human diseases, such as brain ischemia and infections, are associated with and influenced by the activity and serum concentrations of MBL in body fluids. To quantify MBL levels, tests based on ELISA are used, requiring several incubation and washing steps and lengthy turnaround times. Here, we aimed to develop a nanoplasmonic assay for direct MBL detection in human serum at the point of care. Our assay is based on gold nanorods (GNRs) functionalized with mannose (Man-GNRs) an amphiphilic linker. We experimentally determined the effective amount of sugar linked to the nanorods' surface, resulting in an approximate grafting density of 4 molecules per nm, and an average number of 11 to 13 MBL molecules binding to a single nanoparticle. The optimal Man-GNRs concentration to achieve the highest sensitivity in MBL detection was 15 μg·mL. The specificity of the assay for MBL detection both in simple buffer and in complex pooled human sera was confirmed. Our label-free biosensor is able to detect MBL concentrations as low as 160 ng·mL within 15 min directly in human serum a one-step reaction and by using a microplate reader. Hence, it forms the basis for a fast, noninvasive, point-of-care assay for diagnostic indications and monitoring of disease and therapy.
甘露糖结合凝集素 (MBL) 激活补体系统凝集素途径和随后的炎症机制。许多人类疾病（如脑缺血和感染）的发生和结果与体液中 MBL 的活性和血清浓度有关，并受其影响。为了定量 MBL 水平，使用基于 ELISA 的测试，这些测试需要几个孵育和洗涤步骤以及较长的周转时间。在这里，我们旨在开发一种纳米等离子体测定法，用于在现场直接检测人血清中的 MBL。我们的测定法基于用甘露糖 (Man-GNRs) 功能化的金纳米棒 (GNRs)，这是一种两亲性连接物。我们通过实验确定了连接到纳米棒表面的糖的有效量，从而导致表面的接枝密度约为 4 个分子/纳米，并且平均有 11 到 13 个 MBL 分子结合到单个纳米颗粒上。在 MBL 检测中实现最高灵敏度的最佳 Man-GNRs 浓度为 15 μg·mL。在简单缓冲液和复杂混合人血清中，该测定法对 MBL 检测的特异性均得到了证实。我们的无标记生物传感器能够直接在人血清中检测低至 160 ng·mL 的 MBL 浓度，在 15 分钟内完成一步反应，并使用微孔板读数器。因此，它为用于诊断指标的快速、非侵入性、现场即时检测以及疾病和治疗监测奠定了基础。
