title: A new methodology for electrostatic immobilization of a non-labeled single strand DNA onto a self-assembled diazonium modified gold electrode and detection of its hybridization by differential pulse voltammetry.
abstract: In this work, a self-assembled diazonium modified gold electrode (D-MGE) was used for the fabrication of an electrochemical DNA biosensor. For preparation of D-MGE, initially 2-amino-5-mercapto-1, 3, 4-thiadiazole (AMT) self-assembled on gold electrode and a simple diazonation reaction was used to prepare D-MGE. Then, non-labeled single strand DNA (NL-ssDNA) directly was immobilized on D-MGE through electrostatic interaction. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) characterized the DNA biosensor fabrication process with the use of ferro-ferric cyanide as an electrochemical redox indicator. The hybridization capacity of the developed biosensor was monitored with differential pulse voltammetry using [Fe (CN)(6)](4-) as an indicating probe. A wide dynamic detection range (7.9 × 10(-11)-1.2 × 10(-7) mol L(-1)) and a low detection limit (1.4 × 10(-11) mol L(-1)) were achieved for the complementary sequence. In addition, the hybridization specificity experiments showed that the sensing system could accurately discriminate complementary sequence from non-complementary sequences.
authors.affiliation: Faculty of Chemistry, Kharazmi (Tarbiat Moallem) University, Tehran, Iran. mashhadizadeh@tmu.ac.ir
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Mashhadizadeh
authors.forename: Rasoul Pourtaghavi
authors.initials: RP
authors.lastname: Talemi
mesh_terms: D015374:Biosensing Techniques; D004277:DNA, Single-Stranded / Q000032:analysis / Q000737:chemistry*; D058266:Dielectric Spectroscopy; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D009693:Nucleic Acid Hybridization
chemical_list: D004277:DNA, Single-Stranded; D006046:Gold