Amyloid-β (Aβ) is a peptide that is produced in the brain and carried across the blood brain barrier to the blood. It is an important biomarker for the blood-based diagnosis of early stage Alzheimer's disease (AD). However, the challenges of using blood Aβ are that there are several isoforms of the peptide and that the difference in concentration of the peptide in the blood between AD patient and normal individual is extremely low. Here, we developed interdigitated microelectrodes (IMEs) as an impedance biosensor for the blood-based Aβ detection using gold nanoparticles (AuNPs) sandwich assay. It provided logarithmically linear sensitivity and enhancements in the detection limits of approximately 2.87-fold and 74.84%, respectively. We prepared mouse plasma sample from the blood of double-mutated APP/PS1 transgenic (TG) and wild-type (WT) mouse group, and AD diagnostic ability was tested by Aβ detection in the plasma samples. Our results showed that AuNPs sandwich assay assisted Aβ detection successfully discriminated TG and WT mouse groups. Thus, with this sensing system, we detected Aβ with high sensitivity and selectivity. This Aβ sensing system with AuNPs sandwich assay could lead to a significant advance in human blood sample based clinical diagnosis.

淀粉样蛋白-β（Aβ）是一种在大脑中产生并穿过血脑屏障到达血液的肽。它是基于血液的早期阿尔茨海默氏病（AD）诊断的重要生物标志物。然而，使用血液Aβ的挑战在于，存在几种肽的同工型，并且AD患者与正常个体之间的血液中肽的浓度差异非常低。在这里，我们开发了指状微电极（IME）作为阻抗生物传感器，用于使用金纳米颗粒（AuNPs）夹心法进行基于血液的Aβ检测。它提供了对数线性灵敏度，检测限分别提高了约2.87倍和74.84％。我们从双突变APP / PS1转基因（TG）和野生型（WT）小鼠组的血液中制备了小鼠血浆样品，并通过血浆样品中的Aβ检测测试了AD的诊断能力。我们的结果表明，AuNPs夹心测定法辅助Aβ检测成功地区分了TG和WT小鼠组。因此，通过该传感系统，我们以高灵敏度和高选择性检测到了Aβ。这种具有AuNPs夹心测定的Aβ传感系统可能会导致基于人类血液样本的临床诊断取得重大进展。