A Novel Electrochemical Biosensor for Deoxyribonucleic Acid Detection Based on Magnetite Nanoparticles

DNA detection is of great importance for clinical diagnosis and food safety. In the present study, the authors proposed a sensitive electrochemical biosensor for DNA sequence mutation detection based on the separation and enrichment of magnetic nanobeads. For the proposed biosensor, the probe sequences were immobilized on the surface of the carboxyl functioned magnetic nanobead, to recognize the target sequences, and methylene blue was used as a hybridization indicator. In the range of 1.0 × 10−13–1.0 × 10−6M, the concentration of the complementary sequence was linear with the response of the electrochemical signal of MB and the detective limit of target oligonucleotide was 43 fM. The improvement in the detective sensitivity of this biosensor was mainly due to magnetic enrichment and the multiwall carbon nanotube modified electrode.