A label-free electrochemical biosensor with magnetically induced self-assembly for the detection of CYP2C9*3 gene

A label-free electrochemical biosensor with magnetically induced self-assembly based on peptide nucleic acids (PNA) and Fe 3 O 4 /Fe 2 O 3 heteroplasmon nanorods was successfully fabricated to detect the single nucleotide polymorphism (SNP) of CYP2C9*3. The sensitivity of the electrochemical biosensor was improved by introducing PNA and Fe 3 O 4 /Fe 2 O 3 @Au nanocomposites. The Fe 3 O 4 /Fe 2 O 3 @Au nanocomposites were assembled on the surface of the magnetic glassy carbon electrode (MGCE) by magnetic field, and the thiolated PNA were connected to the nanocomposites through Au-S bonds. The biosensor exhibited a good linear correlation between 1 pM and 1 µM (R 2  = 0.9941), and the limit of detection (LOD) and the limit of quantitation (LOQ) were 0.95 pM and 3.18 pM, respectively. Besides, the electrochemical biosensor could recognize single-base mismatch DNA, and it could be stored stably for 15 days at 4 °C.