Detection of Amyloid β Using a Poly-L-Lysine Mediated Nanobiosensor

Amyloid β (Aβ) peptide is secreted from the outside of neural cell by a neural signal pathway and it accumulated each other results in the highly toxicity amyloid plaque which is a critical causative factor in the pathogenesis of Alzheimer's Disease (AD). The peptide is considered to be a potential biomarker to diagnose AD. Here we introduce a novel poly-L-lysine (PLL) mediated nanobiosensor to detect Aβ in vitro. The PLL molecules were utilized as a signal amplifier of Aβ detection. The indirect enzyme-linked immunosorbent assay (ELISA) method and the sandwich ELISA method have tried to the detection of Aβ. A commercially available ELISA plate was modified by PLL using a chemical agent and the amplified amino groups were activated by a functional group for the binding of Aβ. The bound Aβ was further modified with a primary antibody and fluorescence molecules conjugated secondary antibody by the traditional immunochemistry. In the result, the fluorescence intensity was increased by the increasing concentration of Aβ, and the best Aβ detection results were obtained in the PLL mediated indirect ELISA nanobiosensor. We expected that the present method would be optimized and applied for the detection of Aβ in human fluid.