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 (A beta) 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 A beta was detected by the ferro/ferricyanide redox marker. The designed aptasensor was able to detect A beta in a linear range of 0.002-1.28 ng mL(-1) and a limit of detection of 0.4 pg mL(-1) (88.6 amol L-1). The aptasensor was interference-free, and for demonstration of its viability for AB determination in real samples, the human blood serum and artificial cerebrospinal fluid containing A beta were analyzed. The aptasensor is applicable for the assessment and management of Alzheimer's disease at early stages.