title: Polydiacetylene liposome arrays for selective potassium detection.
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.
authors.affiliation: Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Jiseok
authors.initials: J
authors.lastname: Lee
authors.forename: Hyong-Jun
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jinsang
authors.initials: J
authors.lastname: Kim
mesh_terms: D000107:Acetylation; D002942:Circular Dichroism; D008081:Liposomes / Q000737:chemistry*; D046228:Microarray Analysis / Q000379:methods*; D015394:Molecular Structure; D000078789:Polyacetylene Polymer; D011108:Polymers / Q000737:chemistry*; D053279:Polyynes / Q000737:chemistry*; D011188:Potassium / Q000032:analysis*
chemical_list: D008081:Liposomes; D000078789:Polyacetylene Polymer; D011108:Polymers; D053279:Polyynes; C082361:polydiacetylene; D011188:Potassium