DEVELOPMENT OF LABEL FREE GENOMAGNETIC ELECTROCHEMICAL SENSOR

In this work a label-free genomagnetic electrochemical sensor was developed. It uses as bio-recognition element an oligonucletide sequence which is complementary to a specific DNA sequence. Moreover, the probe have the 5'-extremity modified with biotin, and contain the inosine base instead of guanine. Superparamagnetic microparticles modified with streptavidin were used as solid phase to carry out the analysis with the genomagnetic sensor. Actually, the probe is immobilised on the surface of microparticles by using the streptavidin-biotin interaction, and the affinity reaction with the DNA target occurs by incubating an optimised amount of derivatised microparticles with a fixed volume of sample. After magnetic separation, microparticles are concentrated and treated to release the target, which is finally adsorbed onto the surface of a screen-printed carbon-based sensor and electrochemically detected by the oxidation of guanine and adenine bases.

Experiments were then carried out on synthetic oligonucleotide sequences and afterwards on a PCR amplicon.