Rigid DNA Frameworks Anchored Transistor Enabled Ultrasensitive Detection of Aβ-42 in Serum

It is significant to search for ultrasensitive and accurate testing technology for point-of-care monitoring of common diseases at home; for example, monitoring the Aβ-42 level at any time is crucial for patients suffering from Alzheimer's disease. However, accurately monitoring the Aβ-42 level in serum is often thwarted by the challenges in sensitivity and specificity due to the multiplicated contaminations and intricated biofluid environments. Here, we develop a graphene field-effect transistor (G-FET) sensor modified with a type of rigid DNA framework aptamer-tetrahedral DNA nanostructure (TDN) for Aβ-42 detection in serum. The Aβ-42 specific aptamer combined with the rigid tetrahedral nanostructure achieves higher binding affinity and better specificity and anti-fouling ability. The detectable concentration reaches 5 × 10^-18 mol L^-1 in serum, lower than most other assay approaches. Moreover, the sensor rapidly detects the Aβ-42 level in 6 supernatant samples from mice blood within 5 min and achieves high accuracy. This sensitive and specific method enabled by the DNA tetrahedron G-FET sensor has great potential in the monitoring of Alzheimer's disease and other diseases.