Nucleic acid G-quadruplex based label-free fluorescence turn-on potassium selective sensing

Area of Science:

• Biochemistry
• Analytical Chemistry
• Molecular Biology

Background:

• Potassium ion (K+) is crucial for various physiological processes.
• Accurate and selective detection of potassium is vital for clinical diagnostics and biological research.
• Existing methods for potassium detection often require complex procedures or lack selectivity.

Purpose of the Study:

• To develop a label-free, fluorescence turn-on assay for selective potassium ion sensing.
• To utilize G-rich oligonucleotides and their structural changes in response to potassium.
• To achieve sensitive and selective detection of potassium in aqueous solutions.

Main Methods:

• A G-rich oligonucleotide (oligo-Y) was designed to form a stable quadruplex structure in the presence of potassium ions.
• The resistance of the quadruplex structure to nuclease digestion was exploited for selectivity.
• A pyrene probe was used, and its aggregation-induced excimer emission was measured upon interaction with the potassium-bound oligo-Y.

Main Results:

• The G-rich oligonucleotide selectively formed a quadruplex structure with potassium ions.
• The quadruplex structure exhibited significant resistance to nuclease digestion compared to other ions.
• A strong pyrene excimer emission signal was observed, directly proportional to potassium concentration.
• The assay demonstrated high sensitivity and selectivity against common interfering ions.

Conclusions:

• The developed fluorescence turn-on method provides a sensitive and selective approach for label-free potassium detection.
• The assay leverages the unique structural properties of G-rich oligonucleotides in response to potassium.
• This method holds promise for applications in biological and clinical settings requiring accurate potassium quantification.