Determination of β-amyloid oligomer using electrochemiluminescent aptasensor with signal enhancement by AuNP/MOF nanocomposite.

In order to effectively and conveniently detect the β-amyloid oligomer (AβO) for earlier diagnosis of Alzheimer's disease (AD), a disposable aptamer biosensor has been developed with high performance, facile operation, and low cost. Using a nanocomposite by in situ reduction of chloroauric acid to decorate Au nanoparticles (AuNPs) on Fe-MIL-88NH material via Au-N bond to effectively enhance the electrochemiluminescence (ECL) of luminol, the functioned basal electrode provides adequate background for sensing response. When the aptamer is linked via Au-S bond on the surface, the sensor gets the ability of specific recognition and coalescence toward the target (AβO). After incubating the sample on the aptasensor, its ECL signal is inhibited owing to the steric hindrance of the AβO macromolecules. The relative inhibition ratio linearly depends to the logarithm of AβO concentration in the range 0.1 pM to 10 pM, with an LOD of 71 fM. The aptasensor has high selectivity to AβO among its analogs. The recoveries in human serum were 98.9-105.4%. This research provides a new approach for sensitive detection of AβO in clinic laboratories for investigation and diagnosis of AD.