A genosensor based on MNPs/SPE for determination of prostate cancer gene sequence using hemin as an electrochemical indicator

Prostate cancer is a major health burden in all over the world. It is the most common cancer in males and the second leading cause of cancer-related deaths [1]. Genosensors or DNA hybridization biosensors are analytical devices for detection of specific DNA target sequences upon hybridization of the target strand DNA with the complementary probe immobilized on the solid substrate [2]. Electrochemical method can be used for studying of DNA hybridization or its interactions with small molecules and electrochemical transducers are more attractive for monitoring DNA detection at the molecular level and converting the hybridization event into an analytical signal [3]. Electrochemical DNA biosensors rely on the conversion of the DNA base pair recognition events into a useful electrical signal. Recognition of electrochemical DNA hybridization is accomplished via two methods including direct and indirect. Indirect DNA hybridization detection that carry out without any label, the signal induces owing to the inherent oxidation of adenine and guanine bases in DNA strands directly, whereas in indirect method the oxidation or reduction signal of an electroactive indicator causes detection of hybridization event [4].The aim of this project is to identify prostate cancer gene sequence by using a simple and accurate method. For improving the detection sensitivity, a magnetic nanoparticles (MNPs) is used in the construction of the genosensor. MNPs are a kind of well-known nanomaterials with unique properties, such as: high specific surface area, low toxicity, excellent biocompatibility and ease of functionalization with a variety of ligands [5]. In this work, a new electrochemical genosensor based on MNPs modified graphite screen-printed electrode (MNPs/SPE) as transducer and hemin as a new electroactive label 13th Annual Electrochemistry Seminar of Iran Materials and Energy Research Center (MERC), 22- 23 Nov, 2017 19 is described. We used electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques to investigate the hybridization of DNA at the surfaces of MNPs/SPE. Also, the interaction of hemin and DNA is investigated at the surface of the electrode. The reduction peak current of hemin was increased linearly upon increasing the concentration of the target oligonucleotide sequence in the range of 7.5×10-12 to 2.0×10-6M. The limit of detection (LOD) of the genosensor was as low as 1.994×10-12 M.