Department of Chemistry, Hong Kong Baptist University, Hong Kong, China.
Theranostics. 2019 May 9;9(10):2939-2949. doi: 10.7150/thno.29232. eCollection 2019.
Alzheimer's disease (AD), a chronic neurodegenerative disease associated with the loss of neurons in the brain, is the most pervasive type of dementia; 47 million people are affected, and the number is expected to increase to more than 131 million by 2050, according to Alzheimer's Disease International. Both early diagnosis and continuous monitoring are crucial for early intervention, symptomatic treatment, monitoring of the efficacy of intervention and improved patient function. Beta-amyloid peptide, tau, and phosphorylated tau are useful for screening and diagnosis; meanwhile, simultaneous assessment of multiple biomarkers is of paramount importance for accurate disease diagnosis. Herein, we report a direct, inexpensive and ultrasensitive aptamer-based multiplex assay for the quantification of trace amounts of AD biomarkers in both human serum and cerebrospinal fluid (CSF) samples. In this newly developed assay, molecular recognition of an antibody-aptamer pair provides high specificity in target detection, and the use of a DNA amplification strategy affords high sensitivity, allowing quantification of AD biomarkers in both biological fluids in 1.5 h with only a diminutive amount of the sample consumed. A tailor-made turn-on fluorophore, namely, SPOH, was employed to label the antibody-aptamer hybrids and provide a strong fluorescence signal, which was then detected with a total internal reflection fluorescence microscopy electron-multiplying charge-coupled device (TIRFM-EMCCD) imaging system. The simultaneous detection of biomarkers was achieved by a direct shape-coded method in which the nanoplatforms can be distinguished from one another by their morphologies. This assay demonstrated a lower detection limit (in the femtomolar range) for AD biomarkers than the previously reported antibody-antibody method. The developed assay holds tremendous clinical potential for early diagnosis of AD and monitoring of its progression.
阿尔茨海默病（AD）是一种与大脑神经元丧失相关的慢性神经退行性疾病，是最普遍的痴呆症类型；根据阿尔茨海默病国际的数据，全球有 4700 万人受到影响，预计到 2050 年将增加到 1.31 亿以上。早期诊断和持续监测对于早期干预、症状治疗、干预效果监测和改善患者功能都至关重要。β-淀粉样肽、tau 和磷酸化 tau 可用于筛查和诊断；同时，同时评估多个生物标志物对于准确诊断疾病至关重要。在此，我们报告了一种直接、廉价且超灵敏的基于适体的多重分析方法，用于定量人血清和脑脊液（CSF）样本中痕量 AD 生物标志物。在新开发的分析方法中，抗体-适体对的分子识别为目标检测提供了高度特异性，而 DNA 扩增策略的使用则提供了高度敏感性，仅需消耗微量样本即可在 1.5 小时内定量两种生物流体中的 AD 生物标志物。一种特制的开启型荧光染料，即 SPOH，被用于标记抗体-适体杂交物并提供强荧光信号，然后使用全内反射荧光显微镜电子倍增电荷耦合器件（TIRFM-EMCCD）成像系统进行检测。通过直接形状编码方法实现了生物标志物的同时检测，其中纳米平台可以通过其形态彼此区分。该分析方法对 AD 生物标志物的检测下限（在飞摩尔范围内）低于先前报道的抗体-抗体方法。该开发的分析方法具有巨大的临床潜力，可用于 AD 的早期诊断和监测其进展。
