A novel graphene-DNA biosensor for selective detection of mercury ions

作者：Zhang Yang; Zhao Hong^*; Wu Zhijiao; Xue Ying; Zhang Xiaofang; He Yujian; Li Xiangjun; Yuan Zhuobin

来源：Biosensors and Bioelectronics, 2013, 48: 180-187.

DOI：10.1016/j.bios.2013.04.013

• Mercury ions
• Graphene
• Michael addition
• Biosensor
• Nucleic acids

A novel electrochemical biosensor for sensitive and selective detection of mercury (II) ions (Hg2+) based on a DNA grafted graphene is proposed. Graphene oxide (GO) was reduced by dopamine, and then the single-strand probe DNA modified at the 5'-end with an alkylamino modifier (NH2-ssDNA) was grafted on the reduced graphene oxide (RGO) surface via Michael addition reaction. In the presence of Hg2+, the target DNA with four thymine-thymine (T-T) mismatches would hybridize with the probe DNA on the glassy carbon electrode (GCE) through T-Hg2+-T coordination chemistry. The hybridization of the two oligonucleotides leads to the increase in the peak currents of [Ru(NH3)(6)](3+), which could be used for electrochemical sensing of Hg2+. The difference in the value of the peak currents of [Ru(NH3)(6)](3+) before and after DNA hybridization was linear with the concentration of Hg2+ in the range from 8.0 x 10(-9) to 1.0 x 10(-7) M with a linear coefficiency of 0.996. The detection limit was 5.0 x 10(-9) M (S/N=3). The proposed electrochemical biosensor is rapid, convenient and low-cost for effective sensing of Hg2+. Particularly, the proposed method was applied successfully to the determination of Hg2+ in real environmental samples.

• 出版日期2013-10-15
• 单位中国科学院大学