A colorimetric nano-enzyme assay with Ni@Pt nanoparticles as signal labels for rapid and sensitive detection of exosomal Aβ42 in plasma.

A nano-enzyme sandwich assay (SWzyme assay), a colorimetric system based on a biochip and inorganic nano-enzyme for rapid and simple determination of exosomal Aβ42 in plasma is proposed. Anti-CD63 antibody-modified biochips were prepared for plasma exosome capture and synthesized highly catalytic Ni@Pt nanozymes for detecting exosomal Aβ42. The method was able to detect exosomal Aβ42 with a limit of detection (LOD) as low as 4.2×104 particles/mL and a linear range from 104 to 108 particles/mL. By determination of exosomal Aβ42, the SWzyme assay successfully distinguished plasma from Alzheimer's desease (AD) and healthy mice. The SWzyme assay holds promise to serve as diagnostic tools for the early detection of AD and supporting the development of personalized medicine.