Rapid and sensitive detection of potassium ion based on K+-induced G-quadruplex and guanine chemiluminescence

Abstract

A simple and rapid method for detection of potassium ion (K(+)) based on a guanine chemiluminescence (CL) system is presented. In this system, one guanine-rich DNA molecule is used as the recognition element. K(+) can cause the guanine-rich DNA to form a G-quadruplex conformation, resulting in remarkable quenching of the guanine CL intensity of guanine-rich DNA. The CL intensity of this CL system decreased with increasing K(+) concentration, revealing a linear relationship in K(+) concentration range from 3 × 10(-5) to 1 × 10(-3) M. A complete detection process can be accomplished in about 5 min. Other common cations (such as Na(+), NH4 (+), Mg(2+), Ca(2+), Zn(2+), and Pb(2+)) did not notably interfere with K(+) detection. The mechanism of this strategy is also discussed. The sensing strategy is low cost and simple without the requirement of complex labeling of probe DNA. The scheme is applicable to the detection of other guanine-rich aptamer-binding chemicals or biomolecules.

High-Throughput Low-Background G-Quadruplex Aptamer Chemiluminescence Assay for Ochratoxin A Using a Single Photonic Crystal Microsphere

“…Divalent and monovalent cations such as Mg 2+ or Ca 2+ and K + were found to be essential for the specific recognition of OTA by the aptamer. ,, Mg 2+ or Ca 2+ can act as a bridging interaction mediator between the target and the oligonucleotide and enhance binding to the aptamer . K + can induce guanine-rich DNA folding into a stable G-quadruplex conformation because one G-quadruplex has a channel at its center with a diameter that correlates well with the K + radius (1.3 Å) . Here, the different concentrations of Mg 2+ and K + were optimized, and the results are shown in Figure A,B.…”

“…11 K + can induce guanine-rich DNA folding into a stable G-quadruplex conformation because one G-quadruplex has a channel at its center with a diameter that correlates well with the K + radius (1.3 Å). 34 Here, the different concentrations of Mg 2+ and K + were optimized, and the results are shown in Figure 2A,B. The concentrations of Mg 2+ significantly affect the chemiluminescence signal intensities.…”

<p>A sensitive and rapid chemiluminescence immunoassay for point-of-care testing (POCT) of copeptin in serum based on high-affinity monoclonal antibodies via cytokine-assisted immunization</p>

“…Chemiluminescence immunoassays have been widely applied in the routine clinical analysis due to their high sensitivity, wide detection range, methodological reliability, and relative stability 25,26. Recently, magnetic-particles (MPs) have proven to be a suitable tool for highly sensitive detection of various biomarkers due to their higher specific surface area for immobilizing antibody, improved capture efficiency, reduced incubation time, and easy separation 27,28.…”

Highly Selective Detection of K+ Based on a Dimerized G-Quadruplex DNAzyme

“…Figure F shows that presence of a low (10 mM, equivalent to the intracellular sodium concentration) or high (140 mM, equivalent to the intercellular sodium concentration) concentration of NaCl makes little difference in the catalytic activity of the TTAG3/hemin DNAzyme in the KCl range from 10 to 200 mM, which demonstrates the potential application of sensing K + in vivo again, especially considering the highly similar chemical properties between K + and Na + . The TTAG3/hemin DNAzyme is different from all other GQ based K + sensors because its detection is based on the noncovalent dimerization of GQ, − and the exclusively high specificity to K + even in the presence of a high concentration of Na + is the most prominent advantage.…”

“…The TTAG3/hemin DNAzyme system can detect a wide range of K + concentrations of 1–200 mM with a high selectivity even in the presence of a high concentration of Na + and other metal cations. This DNAzyme system’s availability for the dual detection of K + and NH 4 + is a breakthrough in the area of sensing as the noncovalent dimerization of the DNAzyme scaffold has never been applied as a biosensor. − The detection can be monitored by the visible light absorption measurement, fluorescence measurement or easily visualized by the color changes.…”