Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11020650 | Biosensors and Bioelectronics | 2019 | 25 Pages |
Abstract
This study describes a novel electrochemical aptasensor for detection of α-synuclein (α-syn) oligomer, an important biomarker related to Parkinson's and Alzheimer's diseases. The sensing platform is based on exonuclease I (Exo I), terminal deoxynucleotidyl transferase (TdT) and methylene blue. The aptasensor exploits the improved sensitivity because of applications of TdT and Exo I and also a label-free aptamer (Apt). Furthermore, direct immobilization of complementary strand of aptamer (CS) instead of Apt on the surface of electrode prohibits Apt self-assembled monolayer aggregation and keeps the function of the Apt. In the absence of α-syn oligomer, TdT enhances lengths of Apt and CS and so, increases accumulation of methylene blue as redox agent on the surface of electrode, leading to a strong current signal. While in the presence of α-syn oligomer, Exo I digests CS on the electrode surface, resulting in less accumulation of methylene blue on the electrode surface and a weak current signal. The relative electrochemical signal of the aptasensor increased linearly with the logarithm of α-syn oligomer concentration in the range from 60â¯pM to 150â¯nM. The detection limit was 10â¯pM. Furthermore, the sensor showed high precision and repeatability for detection of α-syn oligomer in serum samples.
Related Topics
Physical Sciences and Engineering
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Authors
Seyed Mohammad Taghdisi, Noor Mohammad Danesh, Morteza Alinezhad Nameghi, Mohammad Ramezani, Mona Alibolandi, Mohammad Hassanzadeh-Khayat, Ahmad Sarreshtehdar Emrani, Khalil Abnous,