Utilizing Functionalized Dual-Microbead Interfaces for Measurements of Amyloid-beta (1–42) with Femtomolar Sensitivity

The presence of amyloid-beta (1-42) in CSF and plasma has been implicated as a pathological hallmark of Alzheimer's disease. Here, we demonstrate a high-sensitivity method of detection and quantification for total Aβ42 utilizing two-antibody functionalized microparticles interfaces. Our method of biomarker detection utilizes two types of microbeads: (1) magnetic particles functionalized with monoclonal antibodies and (2) polystyrene particles dual functionalized with monoclonal antibodies and a unique DNA "tag". The bead complex that forms in the presence of the target analyte is detected using qPCR to determine the analyte concentration. To demonstrate our method, we tested for the presence of amyloid-beta (1-42) in Tris buffer. The established limit of detection for this assay is 0.05 pg mL^-1 (12.5 femtomolar) in purified samples This study provides an improved method of protein detection that could be used for the early diagnosis of Alzheimer's disease.