Wang Meijia, Sun Chunyan, Wang Lianying, Ji Xiaohui, Bai Yubai, Li Tiejin, Li Jinghong
College of Chemistry, Jilin University, Changchun 130021, PR China.
J Pharm Biomed Anal. 2003 Dec 4;33(5):1117-25. 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/Fe(CN)6 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.
目标DNA成功固定在与金电极表面半胱胺单层相关的金胶体颗粒上。胶体金在半胱胺修饰的金电极上的自组装可以扩大电极表面积，并极大地提高固定的单链DNA（ssDNA）的量。通过阻抗谱研究发现，由于目标DNA固定过程，金表面上的Fe(CN)6/Fe(CN)6的电子转移过程受到阻碍。然后，固定在金电极上的单链目标DNA与银纳米颗粒-寡核苷酸DNA探针杂交，随后通过氧化金属溶解释放锚定在杂交体上的银金属原子，并通过碳纤维微电极上的阳极溶出伏安法（ASV）间接测定释放的溶解Ag(I)离子。结果表明，该方法在10-800 pmol/l范围内对DNA检测具有良好的相关性，并且能够检测低至5 pmol/l的目标寡核苷酸。
