Aptamer-Based Fluorescence Nanoprobe for Sensitive and Selective Detection of Potassium

Abstract

A new aptamer-based fluorescence nanoprobe for potassium ion (K⁺) has been developed. The nanoprobe employs gold nanoparticles (AuNPs) as the sensing platform and Rhodamine B as the fluorescence indicator. Aptamer acts as the switch of fluorescence signal of Rhodamine B. In the presence of K⁺, aptamer departs from AuNPs as a result of the formation of G-quartets with K⁺, leading to the decrease of fluorescence signals. Under the optimum conditions, the limit of detection (LOD) for K⁺ is as low as 3.8 nM. The proposed method was successfully applied in the determination of K⁺ in human saliva sample.

Keywords:

• Aptamer
• Fluorescence
• Gold nanoparticle
• Potassium
• Rhodamine B

Acknowledgments

The authors acknowledge the support from the National Natural Science Foundation of China (No. 20505004), Outstanding Adult-young Scientific Research Encouraging Foundation of Shandong Province (No. 2008BS03015) and the Doctoral Found of QUST (No. 0022235).