Magnetized carbon nanotubes for visual detection of proteins directly in whole blood.

The authors describe a magnetized carbon nanotube (MCNT)-based lateral flow strip biosensor for visual detection of proteins directly in whole blood avoiding complex purification and sample pre-treatments. MCNT were synthesized by coating Fe3O4 nanoparticles on the shortened multiwalled carbon nanotube (CNT) surface via co-precipitation of ferric and ferrous ions within a dispersion of shorten multiwalled CNTs. The antibody-modified MCNTs were used to capture target protein in whole blood; the formed MCNT-antibody-target protein complexes were applied to the lateral flow strip biosensor, in which a capture antibody was immobilized on the test zone of the biosensor. The captured MCNTs on the test zone and control zone were producing characteristic brown/black bands, and this enabled target protein to be visually detected. Quantification was accomplished by reading the intensities of the bands with a portable strip reader. Rabbit IgG was used as a model target to demonstrate the proof-of-concept. After systematic optimizations of assay parameters, the detection limit of the assay in whole blood was determined to be 10 ng mL-1 (S/N=3) with a linear dynamic range of 10 to 200 ng mL-1. This study provides a rapid and low-cost approach for detecting proteins in blood, showing great promise for clinical application and biomedical diagnosis, particularly in limited resource settings. Combining the superpara-magnetism of Fe3O4 nanoparticles and the outstanding mechanical properties of carbon nanotubes, magnetized carbon nanotube-based lateral flow strip biosensor was first used for visual detection of proteins directly in whole blood avoiding complex purification and sample pretreatment.

作者描述了一种基于磁化碳纳米管（MCNT）的侧向流试纸条生物传感器，用于直接在全血中可视化检测蛋白质，避免了复杂的纯化和样品预处理过程。通过在短多壁碳纳米管（CNT）表面共沉淀铁离子和亚铁离子，将Fe₃O₄纳米颗粒包覆在短多壁碳纳米管表面来合成MCNT。将抗体修饰的MCNT用于捕获全血中的目标蛋白质；将形成的MCNT - 抗体 - 目标蛋白质复合物应用于侧向流试纸条生物传感器，其中捕获抗体固定在生物传感器的检测区。检测区和对照区上捕获的MCNT产生特征性的棕/黑色条带，从而能够目视检测目标蛋白质。通过便携式试纸条读数仪读取条带的强度来进行定量。以兔IgG作为模型目标来证明概念验证。在对检测参数进行系统优化后，确定该检测方法在全血中的检测限为10 ng/mL（信噪比 = 3），线性动态范围为10到200 ng/mL。这项研究为检测血液中的蛋白质提供了一种快速且低成本的方法，在临床应用和生物医学诊断方面，特别是在资源有限的环境中，具有很大的应用前景。 结合Fe₃O₄纳米颗粒的超顺磁性和碳纳米管出色的机械性能，首次将基于磁化碳纳米管的侧向流试纸条生物传感器用于直接在全血中可视化检测蛋白质，避免了复杂的纯化和样品预处理。