title: Femtomolar level detection of RASSF1A tumor suppressor gene methylation by electrochemical nano-genosensor based on Fe3O4/TMC/Au nanocomposite and PT-modified electrode.
abstract: The alterations in DNA methylation pattern have been identified as one of the most frequent molecular phenomenon in human cancers. The RASSF1A tumor suppressor gene was shown to be often inactivated by hypermethylation of its promoter region. In the present study, a novel chip format sandwich electrochemical genosensor has been developed for the analysis of gene-specific methylation using Fe3O4/N-trimethyl chitosan/gold (Fe3O4/TMC/Au) nanocomposite as tracing tag to label DNA probe and polythiophene (PT) as immobilization platform of sensing element. However, no attempt has yet been made to conjugate DNA probe to Fe3O4/TMC/Au nanocomposite as electrochemical label for strip-based genosensing. Cyclic voltammetric (CV) analysis indicated that modification procedure was well performed. Differential pulse voltammetry (DPV) was employed for quantitative assessment of RASSF1A DNA promoter methylation. The electrochemical measurements accomplished using non-specific DNA fragments mixed with samples, revealed the high specificity and selectivity in methylation analysis by means of this DNA nanobiosensor. With the linear range of concentration from 1 × 10(-14)M to 5 × 10(-9)M and the detection limit of 2 × 10(-15)M, this new strategy has shown such a promising application to be used for universal analysis of any DNA sequence.
authors.affiliation: Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Daneshpour
authors.affiliation: Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Leila Syed
authors.initials: LS
authors.lastname: Moradi
authors.affiliation: Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Pantea
authors.initials: P
authors.lastname: Izadi
authors.affiliation: Biosensor Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: omidfar@tums.ac.ir.
authors.forename: Kobra
authors.initials: K
authors.lastname: Omidfar
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D003217:Conductometry / Q000295:instrumentation*; D019175:DNA Methylation; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics; D004867:Equipment Design; D019544:Equipment Failure Analysis; D016147:Genes, Tumor Suppressor; D006046:Gold / Q000737:chemistry; D006801:Humans; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008832:Microchemistry / Q000295:instrumentation; D008839:Microelectrodes; D008904:Miniaturization; D053761:Nanocomposites / Q000737:chemistry / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation; D010984:Platinum / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025521:Tumor Suppressor Proteins / Q000097:blood* / Q000235:genetics*
chemical_list: D015342:DNA Probes; D058185:Magnetite Nanoparticles; C411762:RASSF1 protein, human; D025521:Tumor Suppressor Proteins; D010984:Platinum; D006046:Gold; D048271:Chitosan
keywords: DNA methylation; Fe(3)O(4)/TMC/Au nanoparticle; Nano-genosensor; RASSF1A; anti-5-methylcytosine antibody; polythiophene