Label-free fluorescent aptasensor for potassium ion using structure-switching aptamers and berberine

Area of Science:

• Analytical Chemistry
• Biochemistry
• Materials Science

Background:

• Potassium ion (K+) is crucial for physiological functions.
• Accurate K+ ion monitoring is essential for clinical diagnostics.
• Existing detection methods often lack simplicity, speed, or sensitivity.

Purpose of the Study:

• To develop a simple, rapid, and label-free fluorescent aptasensor for K+ ion detection.
• To utilize G-rich single-stranded DNA (ssDNA) and berberine for K+ ion sensing.
• To validate the aptasensor's performance in aqueous solutions and biological samples.

Main Methods:

• Fabrication of a fluorescent aptasensor using G-rich ssDNA and berberine.
• Exploitation of K+ ion-induced G-quadruplex formation in ssDNA.
• Berberine binding to G-quadruplex enhances fluorescence for K+ ion detection.

Main Results:

• The aptasensor showed a linear response for K+ ion in the range of 0-1600 μM.
• A low detection limit of 31 nM (S/N=3) was achieved.
• The sensor demonstrated high accuracy (81.7-105.3% recovery) in blood serum samples with a low RSD of 0.45%.

Conclusions:

• A robust, economical, and stable label-free fluorescent aptasensor for K+ ion detection was successfully developed.
• The aptasensor is suitable for practical analysis of K+ ion in complex matrices like blood serum.
• This method offers a convenient and effective approach for potassium ion quantification.