DNAzyme-driven bipedal DNA walker triggered to hybridize silver nanoparticle probes for electrochemical detection of amyloid-β oligomer

Amyloid-beta oligomer has been considered as a promising molecular biomarker for the diagnosis of Alzheimer's disease due to their significant neural synapse toxicity. Therefore, it is essential to create an easy approach for the selective detection of Amyloid-beta oligomer that has high sensitivity and cheap cost. In this work, we developed an innovative enzyme-free electrochemical aptasensor based on the DNAzyme-driven DNA bipedal walker tactics for sensing Amyloid-beta oligomer. Bipedal DNA walkers demonstrate a wider walking region, better walking ki-netics, and higher amplification effectiveness than typical DNA walkers. The Mg2+-dependent DNAzyme drove the DNA walker, and the binding-induced DNA walker can sequentially shear MBs and form MB fragment structure. Finally, the detection probes modified AgNPs hybridized with the MB fragment structure, resulting in the multiplication of AgNPs on the electrode surface. Electrochemical stripping of AgNPs was used to test the performance of the obtained electrochemical sensor. In particular, a low detection limit of 5.94 fM and a wide linear range of 0.01 pM-0.1 nM were attained. The detection of Amyloid-beta oligomer in human serum was then carried out using this bipedal DNA walker biosensor, which shown good selectivity and outstanding reproduc-ibility, indicating its usefulness in bioanalysis.

Automated summary

Researchers developed an innovative enzyme-free electrochemical aptasensor for the selective detection of Amyloid-beta oligomer. The DNAzyme-driven DNA bipedal walker tactics showed high sensitivity and low cost, and were successfully used to detect Amyloid-beta oligomer in human serum.