Lee Taeha, Kim Woong, Park Jinsung, Lee Gyudo
Department of Biotechnology and Bioinformatics, Korea University, Sejong 30019, Korea.
Interdisciplinary Graduate Program for Artificial Intelligence Smart Convergence Technology, Korea University, Sejong 30019, Korea.
Materials (Basel). 2022 Nov 3;15(21):7738. doi: 10.3390/ma15217738.
Immunoglobulin detection is important for immunoassays, such as diagnosing infectious diseases, evaluating immune status, and determining neutralizing antibody concentrations. However, since most immunoassays rely on labeling methods, there are limitations on determining the limit of detection (LOD) of biosensors. In addition, although the antigen must be immobilized via complex chemical treatment, it is difficult to precisely control the immobilization concentration. This reduces the reproducibility of the biosensor. In this study, we propose a label-free method for antibody detection using microcantilever-based nanomechanical resonators functionalized with erythrocyte membrane (EM). This label-free method focuses on the phenomenon of antibody binding to oligosaccharides (blood type antigen) on the surface of the erythrocyte. We established a method for extracting the EM from erythrocytes and fabricated an EM-functionalized microcantilever (MC), termed EMMC, by surface-coating EM layers on the MC. When the EMMC was treated with immunoglobulin M (IgM), the bioassay was successfully performed in the linear range from 2.2 pM to 22 nM, and the LOD was 2.0 pM. The EMMC also exhibited excellent selectivity compared to other biomolecules such as serum albumin, γ-globulin, and IgM with different paratopes. These results demonstrate that EMMC-based nanotechnology may be utilized in criminal investigations to identify blood types with minimal amounts of blood or to evaluate individual immunity through virus-neutralizing antibody detection.
免疫球蛋白检测对于免疫分析非常重要，例如诊断传染病、评估免疫状态以及测定中和抗体浓度。然而，由于大多数免疫分析依赖标记方法，在确定生物传感器的检测限（LOD）方面存在局限性。此外，尽管抗原必须通过复杂的化学处理进行固定，但难以精确控制固定浓度。这降低了生物传感器的重现性。在本研究中，我们提出了一种基于微悬臂梁的纳米机械谐振器的无标记抗体检测方法，该谐振器用红细胞膜（EM）进行功能化。这种无标记方法关注抗体与红细胞表面寡糖（血型抗原）结合的现象。我们建立了从红细胞中提取EM的方法，并通过在微悬臂梁（MC）表面涂覆EM层制备了一种EM功能化的微悬臂梁（MC），称为EMMC。当用免疫球蛋白M（IgM）处理EMMC时，生物测定在2.2 pM至22 nM的线性范围内成功进行，检测限为2.0 pM。与具有不同抗原决定部位的其他生物分子如血清白蛋白、γ球蛋白和IgM相比，EMMC还表现出优异的选择性。这些结果表明，基于EMMC的纳米技术可用于刑事调查，以用微量血液鉴定血型或通过病毒中和抗体检测评估个体免疫力。
