JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, v.130, no.15, pp.5010 - 5011
Abstract
Potassium is an important cation in biology, and quantitative detection of the extracellular potassium level is important. However, selective detection of extracellular physiological potassium is a challenging task due to the presence of sodium in a much higher concentration. In this contribution, we describe the development of practical polydiacetylene (PDA) liposome-based microarrays to selectively detect potassium even in the presence of sodium. We utilize the fact that the G-rich ssDNA can fold into a G-quadruplex via intramolecular hydrogen bonding by wrapping around a potassium ion exclusively. We rationally design the PDA liposome in such a way that the G-rich ssDNA probes are presented densely at the liposome surface and form bulky quadruplexes upon binding with K+. The resulting bulky quadruplexes are sterically hindered and repulse each other and impose mechanical stress on the PDA backbone, resulting in the conformational change of the ene-yne backbone of the PDA. As a result, polydiacetylene liposomes turn into the emissive red phase from the nonfluorescent blue phase.