运用交流阻抗技术直接监测DNA杂交  

Direct Detection of DNA Hybridization by Impedance Technique

作　　者：徐颖[1] 杨琳[1] 叶晓燕[1] 何品刚[1] 方禹之[1] 

机构地区：[1]华东师范大学化学系,上海200062

出　　处：《华东师范大学学报（自然科学版）》2006年第4期39-48,共10页Journal of East China Normal University(Natural Science)

基　　金：国家自然科学基金(29875008)

摘　　要：介绍了基于交流阻抗技术构建非标记型脱氧核糖核酸(DNA)杂交传感器的方法．以24个碱基长度的寡聚DNA作为实验对象,将5′端巯基化的单链寡聚DNA(SH-ssDNA)探针与巯基乙酸(RSH)同时自组装到金电极表面,形成杂交识别层,利用交流阻抗技术测量出杂交前后金电极表面电子传递电阻R_(et)的增量作为杂交信号．实验中对DNA探针的自组装时间、杂交温度、杂交时间和阻抗测量液等实验条件进行了观察和优化；通过选择自组装液中SH-ssDNA探针和RSH的浓度,减少DNA在金电极表面的非特异性吸附,同时保证金电极表面自组装的SH-ssDNA探针有合适的疏密度,提高了杂交效率．在各优化条件下,无需扩增杂交信号,此非标记型DNA杂交传感器的检测下限为3．0×10^(-14)mol/L；和完全互补序列相比,一个和三个碱基错配序列分别产生55．6％和1．3％的杂交信号．A label-free DNA hybridization biosensor based on impedance technique was introduced. A 24-mer 5＇-mercapto-group ended single-stranded DNA probe （SH-ssDNA） was self-assembled onto Au electrode surface with mercaptoacetic acid （RSH） to form a recognition layer. By Faradic impedance technique, a significant increase of the interracial electronic transfer resistance Ret was determined when the SH-ssDNA probe/Au electrode hybridized with its complementary sequence. Further, several experimental conditions, including the SH-ssDNA probe immobilization time, hybridization temperature and time, the eletrolyte for impendance detections were optimized. Especially, the proportion of SH-ssDNA and RSH in the immobilization solution was important for a suitable density of ssDNA probe on electrode surface to improve the hy bridization efficiency. Based on these optimized conditions, this label-free DNA hybridization biosensor has a low detection limit of 3.0 × 10^-14 mol/L of complementary sequence in solution. When compared with the complementary sequence, the hybridization signal of one-base mismatched sequence and three-base mismatched sequence was 55.6% and 1.3% respectively.

关 键 词：DNA杂交传感器 交流阻抗 非标记法 

分 类 号：O657.1[理学—分析化学]