A label-free fluorescent biosensor for ultratrace detection of terbium (III) based on structural conversion of G-quadruplex DNA mediated by ThT and terbium (III)

作者：Chen, Qiang; Zuo, Junfeng; Chen, Jinfeng; Tong, Ping; Mo, Xiujuan; Zhang, Lan^*; Li, Jianrong

来源：Biosensors and Bioelectronics, 2015, 72: 326-331.

DOI：10.1016/j.bios.2015.04.039

• Thioflavin T
• G-quadruplex
• Fluorescent biosensor
• Terbium (III)

In this paper, a novel label-free fluorescent biosensor for terbium (III) (Tb3+) was proposed based on structural conversion of G-quadruplex DNA mediated by Thioflavin T (ThT) and Tb3+. In the presence of K+, ThT could bind to K+-stabilized parallel G-quadruplex, giving rise to high fluorescence intensity. Upon the addition of Tb3+, Tb3+ could competitively bind to parallel G-quadruplex leading to the structural change, which resulted in fluorescence decrease. The change of fluorescence intensity (Delta F=F-0-F) showed a good linear response toward the concentration of Tb3+ over the range from 1.0 pM to 10.0 mu M with a limit of detection of 0.55 pM. This proposed biosensor was simple and cost-effective in design and in operation with ultrahigh sensitivity and selectivity. Thus, the proposed biosensor could be a promising candidate for monitoring ultratrace Tb3+ in environment.

• 出版日期2015-10-15
• 单位中国环境监测总站; 福州大学; 浙江工商大学; 渤海大学