Highly Sensitive and Selective Potassium Ion Detection Based on Graphene Hall Effect Biosensors

• Main Authors: Xiangqi Liu, Chen Ye, Xiaoqing Li, Naiyuan Cui, Tianzhun Wu, Shiyu Du, Qiuping Wei, Li Fu, Jiancheng Yin, Cheng-Te Lin
• Format: Article
• Language: English
• Published: MDPI AG 2018-03-01
• Series: Materials
• Subjects: single-layer graphene; Hall effect biosensor; guanine-rich DNA strand; guanine-quadruplexes; potassium ions
• Online Access: http://www.mdpi.com/1996-1944/11/3/399

Potassium (K+) ion is an important biological substance in the human body and plays a critical role in the maintenance of transmembrane potential and hormone secretion. Several detection techniques, including fluorescent, electrochemical, and electrical methods, have been extensively investigated to selectively recognize K+ ions. In this work, a highly sensitive and selective biosensor based on single-layer graphene has been developed for K+ ion detection under Van der Pauw measurement configuration. With pre-immobilization of guanine-rich DNA on the graphene surface, the graphene devices exhibit a very low limit of detection (≈1 nM) with a dynamic range of 1 nM–10 μM and excellent K+ ion specificity against other alkali cations, such as Na+ ions. The origin of K+ ion selectivity can be attributed to the fact that the formation of guanine-quadruplexes from guanine-rich DNA has a strong affinity for capturing K+ ions. The graphene-based biosensors with improved sensing performance for K+ ion recognition can be applied to health monitoring and early disease diagnosis.