| 摘要: | 阿茲海默症(Alzheimer′s disease, AD)是最常見的癡呆症，全世界患病人數呈上升趨勢，目前尚無實質的治療和預防方法。然而現今普遍之診斷方法因價格高昂、具有侵入性等因素而無法廣泛篩檢，導致早期檢測受到限制。研究表明血漿中的澱粉樣蛋白(amyloid beta, Aβ)之水平變化與疾病發展相關，因此已被研究作為候選生物標記物，其中 Aβ 42/40 血漿中的莫耳比隨著病程發展呈現負相關，更能作為阿茲海默症臨床試驗中的縱向分析(longitudinal analysis)依據。因此，本研究致力於開發一種早期檢測方法，使用磁性奈米粒子及量子點複合物的診斷技術。具體而言，利用 Aβ42 和 Aβ40及其與各自抗體之特異性捕獲血漿中的澱粉樣蛋白，再配合量子點高亮度和光穩定性之特性及磁性奈米粒子的順磁性執行定向分析策略(direct assay strategy, DAS)及反向分析策略(reverse assay strategy, RAS)，從而提升檢測靈敏度。我們成功地利用此檢測系統測定了 Aβ42 和 Aβ40。最低檢測濃度為0.1 μM，且在 0.4 至 2 μM 的濃度範圍內，螢光強度與濃度呈線性關係。最後，通過固定一種蛋白的濃度並改變另一種蛋白的濃度，成功分析 Aβ42/40比例的變化，驗證了系統的準確性和穩定性。此種方法不僅達到便利且低侵入性，並且為早期診斷提供一個新選擇。
;Alzheimer′s disease (AD) stands as the predominant form of dementia worldwide, with its prevalence on a steady rise. Despite this escalating burden, effective treatments or preventive measures remain elusive. Challenges persist in
the realm of diagnostics, where existing methods often prove inaccessible for extensive AD screening due to exorbitant costs and invasiveness. Measuring the concentrations of amyloid beta (Aβ), a protein family believed to be involved in AD pathogenesis, in the blood plasma has emerged as a promising diagnostic, owing to the correlation of the Aβ concentrations, particularly the Aβ42/Aβ40 molar ratio, with AD progression. This ratio presents an opportunity for
comprehensive longitudinal analysis in AD clinical trials. In this vein, our study sets out to develop an approach for early AD detection, leveraging the technique based on magnetic nanoparticles and quantum dot complexed with anti-Aβantibodies. By harnessing the specificity between Aβ42 and Aβ40 and their respective antibodies, our technique captures the two proteins with high precision and efficiency. Crucially, we exploit the high brightness and photostability
characteristics of quantum dots and the paramagnetism of magnetic nanoparticles to enact both directed assay strategies (DAS) and reverse assay strategies (RAS),
which enhances the detection sensitivity. We successfully utilized the detection system to measure Aβ42 and Aβ40, achieving a lowest detectable concentration of 0.1 μM. Within the 0.4 to 2 μM range, fluorescence intensity exhibited a linear relationship with concentration. In addition, effectively analyzed changes in the Aβ42/40 ratio, thereby validating the accuracy and stability of the system.
Through this integrated approach, our method not only facilitates convenient and minimally invasive diagnosis but also heralds a transformative pathway for early detection in AD. |
