Design and application of electrochemical genosensor for identification of prostate cancer gene sequence

Prostate cancer is the most frequently diagnosed type of cancer and the second leading cause of cancer-related mortality in men in recent years [1]. Biosensors are small devices employing biochemical, molecular recognition properties as a basis for selective analysis. Biosensors offer exciting opportunities for numerous decentralized clinical applications, due to their specificity, speed, portability and low cost [2]. The aim of this project is to identify prostate cancer gene sequence by using a simple and accurate method. Lately, many types of magnetic nanocomposite are widely used for electrochemical biosensor, because of their conducting and high surface-to-volume ratio. For improving the detection sensitivity, magnetic nanocomposite are used in the construction of the biosensor. Magnetic nanocomposite are a kind of well-known bio- magnetic nanocomposite with unique properties of a high specific surface area, low toxicity, the excellent biocompatibility and ease of functionalization with a variety of ligands [3].Among several nanomaterials, functionalized magnetic nanocomposite modified graphite screen printed electrode offered the best electrochemical response for the aim of this project.The graphite screen printed electrode was modified by functionalized magnetic nanocomposite. Electrochemical biosensor was prepared by applying specific potential for immobilizing of single stranded oligonucleotide (ssDNA) of prostate cancer genes on the modified graphite screen printed electrode (probe). Hybridization between the immobilized ssDNA on the biosensor and it s complementary DNA was shown by using differential pulse voltammetry (DPV). The peak currents of guanines increased linearly upon increasing the concentration of the target oligonucleotide sequence in the range of 2.0×10-6 to 1×10-11 M. The detection limit (LOD) of the genosensor was as low as 8.4×10-12 M.