Electrochemical detection of DNA immobilized on gold colloid particles modified self-assembled monolayer electrode with silver nanoparticle label

• Published in: Journal of pharmaceutical and biomedical analysis Vol. 33; no. 5; pp. 1117 - 1125
• Main Authors: Wang, Meijia, Sun, Chunyan, Wang, Lianying, Ji, Xiaohui, Bai, Yubai, Li, Tiejin, Li, Jinghong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 04.12.2003; Elsevier Science
• Subjects: Analysis; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Colloidal Au; Cross-Linking Reagents - analysis; Cysteamine - analysis; DNA; DNA - analysis; Electrochemistry; Fundamental and applied biological sciences. Psychology; General pharmacology; Gold Colloid - analysis; Impedance spectroscopy; Ion-Selective Electrodes - standards; Medical sciences; Nanotechnology - methods; Pharmacology. Drug treatments; Self-assembled monolayer; Silver - analysis; Silver nanoparticles label; Spectrophotometry, Ultraviolet; Self-assembled monolayer; Colloidal Au; Impedance spectroscopy; Silver nanoparticles label; DNA; Particle; Silver; Nanoparticle; Self-assembled monolayer: Impedance spectroscopy; Colloidal Au: DNA; Electrochemical detector
• ISSN: 0731-7085; 1873-264X
• DOI: 10.1016/S0731-7085(03)00411-4

The target DNA was immobilized successfully on gold colloid particles associated with a cysteamine monolayer on gold electrode surface. Self-assembly of colloidal Au onto a cysteamine modified gold electrode can enlarge the electrode surface area and enhance greatly the amount of immobilized single stranded DNA (ssDNA). The electron-transfer processes of [Fe(CN) 6] 4−/[Fe(CN) 6] 3− on the gold surface were blocked due to the procedures of the target DNA immobilization, which was investigated by impedance spectroscopy. Then single stranded target DNA immobilized on the gold electrode hybridized with the silver nanoparticle–oligonucleotide DNA probe, followed by the release of the silver metal atoms anchored on the hybrids by oxidative metal dissolution, and the indirect determination of the released solubilized Ag I ions by anodic stripping voltammetry (ASV) at a carbon fiber microelectrode. The results show that this method has good correlation for DNA detection in the range of 10–800 pmol/l and allows the detection level as low as 5 pmol/l of the target oligonucleotides.