Colorimetric detection of potassium ions using aptamer-functionalized gold nanoparticles

Area of Science:

• Analytical Chemistry
• Biotechnology
• Nanotechnology

Background:

• Potassium ions (K(+)) are crucial for physiological processes.
• Accurate detection of K(+) is vital for clinical diagnostics and environmental monitoring.
• Existing methods for K(+) detection can be complex or lack sensitivity.

Purpose of the Study:

• To develop a simple, novel, and highly sensitive colorimetric method for potassium ion (K(+)) detection.
• To utilize the conformational change of an anti-K(+) aptamer and gold nanoparticles (AuNPs) for visual K(+) sensing.

Main Methods:

• A colorimetric aptasensor was designed based on the conformational change of an anti-K(+) aptamer.
• The aptamer undergoes a structural transition to a G-quadruplex in the presence of K(+).
• This structural change influences the aggregation of gold nanoparticles (AuNPs), leading to a visible color change.

Main Results:

• The developed aptasensor exhibited a distinct color change from wine-red to blue-purple upon K(+) addition, observable by the naked eye.
• A wide linear detection range for K(+) was achieved, from 5 nM to 1 μM.
• A low detection limit of 5 nM for K(+) was determined, demonstrating high sensitivity.
• The assay demonstrated high selectivity for K(+) detection.

Conclusions:

• The novel colorimetric aptasensor provides a simple and effective method for detecting potassium ions (K(+)).
• The assay's high sensitivity, selectivity, and visual readout indicate significant potential for practical applications in K(+) monitoring.