Fluorophore Label-Free Light-up Near Infrared Deoxyribonucleic Acid Nanosensor for Monitoring Extracellular Potassium...

Area of Science:

• Biomedical Engineering
• Molecular Imaging
• Nanotechnology

Background:

• Near-infrared (NIR) fluorescence imaging offers advantages like deep tissue penetration and low background noise for nanosensors.
• Efficient NIR quenchers are challenging to design, synthesize, and modify, hindering NIR DNA nanosensor development.
• Label-free strategies using G-quadruplex (G4) and NIR dyes are emerging for in situ extracellular imaging.

Purpose of the Study:

• To propose a novel NIR sensing strategy for specific extracellular target detection.
• To develop a simplified approach avoiding complex synthesis and site-specific modification.
• To create a light-up NIR DNA nanosensor for monitoring extracellular potassium ion (K+) concentrations.

Main Methods:

• Constructed a potassium ion (K+)-sensitive G4 chain (PS2.M) to form a G4 nanostructure in the presence of K+.
• Utilized the G4 nanostructure formation to activate a near-infrared G4 dye (CSTS), generating NIR signals.
• Incorporated cholesterol into the nanosensor for cellular application and feedback on extracellular K+ changes.

Main Results:

• The developed nanosensor demonstrates a rapid response to K+ within a linear range of 5-50 mM.
• The nanosensor exhibits good resistance to interference, ensuring reliable measurements.
• The cholesterol-modified nanosensor successfully provided feedback on extracellular K+ concentration changes in various cell types.

Conclusions:

• The proposed label-free strategy simplifies NIR DNA nanosensor design and synthesis.
• The K+-sensitive G4 nanosensor is a potential tool for studying diseases like epilepsy and cancer.
• This strategy holds promise for the NIR detection of diverse extracellular targets using aptamers and DNAzymes.