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

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Molecular Diagnostics

Background:

• Accurate monitoring of amyloid-beta 42 (Aβ-42) is crucial for Alzheimer's disease (AD) management.
• Existing methods for Aβ-42 detection in serum face challenges in sensitivity, specificity, and susceptibility to contamination.
• Point-of-care testing requires highly sensitive and specific diagnostic tools for home use.

Purpose of the Study:

• To develop an ultrasensitive and accurate sensor for detecting Aβ-42 levels in serum for Alzheimer's disease monitoring.
• To enhance sensor performance by utilizing a rigid DNA framework aptamer-tetrahedral DNA nanostructure (TDN).
• To overcome limitations of existing assays regarding sensitivity, specificity, and biofluid interference.

Main Methods:

• Graphene field-effect transistor (G-FET) sensor fabrication.
• Modification of G-FET with a DNA aptamer and tetrahedral DNA nanostructure (TDN) for Aβ-42 specific binding.
• Testing sensor performance in human serum samples for Aβ-42 detection.

Main Results:

• The developed G-FET sensor, modified with TDN, demonstrated high binding affinity and specificity for Aβ-42.
• Achieved a detectable concentration as low as 5 × 10^-18 mol L^-1 in serum, surpassing many existing assays.
• Rapidly and accurately detected Aβ-42 levels in mouse blood supernatant samples within 5 minutes.

Conclusions:

• The DNA tetrahedron G-FET sensor offers a highly sensitive and specific platform for Aβ-42 detection.
• This technology shows significant potential for point-of-care monitoring of Alzheimer's disease and other conditions.
• The developed sensor addresses key challenges in biofluid analysis for disease diagnostics.