An ultrasensitive electrochemical aptasensor for early diagnosis of Alzheimer's disease, using a fern leaves-like gold nanostructure.

An extremely sensitive and highly simple aptasensor was fabricated for quantitation of amyloid beta (Aβ) by electrochemical transduction of a fern leaves-like gold nanostructure. The gold nanostructure was synthesized by electrodeposition using polyethylene glycol 6000 as a shape-directing agent, and characterized electrochemically and by field emission scanning electron microscopy. A specific RNA aptamer was immobilized on the fern leaves-like gold nanostructure, and binding with Aβ was detected by the ferro/ferricyanide redox marker. The designed aptasensor was able to detect Aβ in a linear range of 0.002-1.28 ng mL and a limit of detection of 0.4 pg mL (88.6 amol L). The aptasensor was interference-free, and for demonstration of its viability for Aβ determination in real samples, the human blood serum and artificial cerebrospinal fluid containing Aβ were analyzed. The aptasensor is applicable for the assessment and management of Alzheimer's disease at early stages.