Kong Xiaoming, Li Chao, Li Yang, Song Xueqian, Huang Lin
Affiliated Psychological Hospital of Anhui Medical University, Anhui Mental Health Center, Hefei Fourth People's Hospital, 316 Huangshan Road, Hefei, 230022, China.
School of Life Sciences, Anhui Medical University, Hefei, Anhui 230032, China.
Analyst. 2025 Apr 8;150(8):1670-1678. doi: 10.1039/d5an00013k.
Exosomes, which are recognized as a kind of valuable liquid biopsy biomarker, exhibit significant application potential in cancer diagnosis. Therefore, it is crucial to establish a reliable detection method for their clinical application. In this study, we have presented an ultrasensitive aptasensor for the visual detection of exosomes by employing tyramine-assisted dual-signal amplification technology. First, we utilized magnetic beads modified with the nucleolin aptamer (MNPs-Apt) to capture exosomes. This modification not only enhanced specificity, but also reduced interference of complex sample components. The captured exosomes as a rich source of proteins can bind with multiple biotinyl-tyramide (Bio-TR) molecules through a catalytic reaction involving horseradish peroxidase (HRP) and HO. Second, streptavidin-HRP complex-modified gold nanoparticles (GNPs-Str-HRP) as a signal amplification probe was introduced to further enhance the detection signal by binding to Bio-TR. Lastly, the addition of 3,3',5,5'-tetramethylbenzidine (TMB) solution induced a visible color change, enabling quantification of the exosome concentration. This dual-signal amplification strategy resulted in a low limit of detection (LOD) of 63 particles per μL, and it also demonstrated accurate visual diagnosis capabilities for clinical samples. The successful implementation of this approach suggests its potential as a promising tool for point-of-care testing (POCT) in cancer diagnostics.
外泌体被认为是一种有价值的液体活检生物标志物，在癌症诊断中具有显著的应用潜力。因此，建立一种可靠的检测方法以用于其临床应用至关重要。在本研究中，我们提出了一种利用酪胺辅助双信号放大技术对外泌体进行可视化检测的超灵敏适体传感器。首先，我们使用核仁素适体修饰的磁珠（MNPs-Apt）来捕获外泌体。这种修饰不仅提高了特异性，还减少了复杂样品成分的干扰。捕获的外泌体作为丰富的蛋白质来源，可以通过涉及辣根过氧化物酶（HRP）和HO的催化反应与多个生物素化酪胺（Bio-TR）分子结合。其次，引入链霉亲和素-HRP复合物修饰的金纳米颗粒（GNPs-Str-HRP）作为信号放大探针，通过与Bio-TR结合进一步增强检测信号。最后，加入3,3',5,5'-四甲基联苯胺（TMB）溶液会引起可见的颜色变化，从而能够对外泌体浓度进行定量。这种双信号放大策略导致低检测限（LOD）为每微升63个颗粒，并且还展示了对临床样品进行准确可视化诊断的能力。该方法的成功实施表明其作为癌症诊断中即时检测（POCT）的有前景工具的潜力。
