▎ 摘　　要

Highly sensitive and easy detection method for Alzheimer's disease (AD) with a suitable biomarker is mandatory for preventing the factors resulting from AD. This research reports a modified ELISA with graphene for the detection of AD biomarker amyloid beta (A beta) oligomer. Gold nanoparticle (AuNP) conjugated aptamer was used as the capture probe and attached on ELISA-graphene oxide surface through the amine linker. Antibody was used as the detection molecule to reach the maximum detection of A beta oligomer. Suitable level of APTMS (2%), size of AuNP (30 nm) and aptamer concentration (2 mu M) were optimized. This sandwich pattern of aptamer-A beta oligomer-antibody helps to reach the detection at 50 pM on the optimized ELISA surface and the control experiments in the absence of A beta oligomer or anti-A beta oligomer antibody did not show the significant optical detection at 492 nm, indicting the specific detection. Further, A beta oligomer spiked artificial cerebrospinal fluid did not interfere the detection of A beta oligomer, confirming the selective detection. This new and modified ELISA surface helps to reach the lower detection of A beta oligomer and diagnose AD.