Detection of sequence-selective nucleic acid hybridization based on magnetic particles by electrochemical sensors

Nucleic acids store genetic information of an organism and all transfers to the new generations. Nucleic acids also administer basic life events such as the cell growth, the synthesis of proteins and enzymes. Recognition surfaces of nucleic acid have becomed more interesting with each passing day for the analytical chemistry. Electrochemical DNA biosensors based on nucleic acid analysis is thought to play a crucial role in the analyzes to be made at the bedside in a doctor's supervision in the future. In the field of biotechnology, studies based DNA analyzes with using magnetic particles and detection of sequence specific nucleic acid hybridization with electrochemical sensor have increased in recent years. In our study, realization of sequence-selective nucleic acid hybridization the most selective and effective at surface of magnetic nanoparticles and after detection based voltammetric method of DNA hybridization with disposable electrochemical sensor technology have been aimed. After synthesis of amino link magnetic nanoparticles, microscopic characterization with scanning electron microscopy (SEM) and spectroscopic characterization with Fourier transform infrared spectroscopy (FTIR) have been made. Moreover, the magnetic property of the magnetic nanoparticles has been shown with electron spin resonance (ESR) spectrometer. Throughout our study, studies of the store buffer solution has been investigated. So that the the buffer solution which nanoparticles remain more stable has been investigated, and then studies were continued this buffer solution. In the second part of this study, optimization studies have carried out onto the surface of amino linked magnetic nanoparticles distributed in chosen buffer solution for the analysis of DNA hybridization. The DNA probe representing to the Hepatitis B virus (HBV) concentration, target DNA concentration, the most productive hybridization time and the selection versus other DNA sequences have been researched. After the DNA hybrid detached from the surface of the particle with alkaline treatment, hybrid have been immobilized surface of disposable pencil graphite electrode (PGE). The electrochemical behavior of the DNA was immobilized on the surface of PGE has been investigated with using differential pulse voltammetry (DPV) technique by the measuring signal change of guanine oxidation. Consequently, the analysis of sequence-selective HBV DNA hybridization has been performed in a good reproducubility with sensitivity and selectivity by using this electrochemical sensor technology based on magnetic nanoparticles. Keywords: Magnetic nanoparticle, disposable graphite electrode, electrochemical sensor, differential pulse voltammetry, HBV DNA.