A DNA small molecular probe with increasing K⁺ concentration promoted selectivity

Area of Science:

• Chemical Biology
• Molecular Biology
• Biotechnology

Background:

• DNA small molecular probes are crucial for diagnosing DNA-related diseases.
• Previous studies often required specific salinity conditions, limiting universal application.
• Developing versatile probes adaptable to varying ionic environments is essential.

Purpose of the Study:

• To synthesize and characterize a novel DNA probe, 4-imino-3-(pyridin-2-yl)-4H-quinolizine-1-carbonitrile (IPQC).
• To investigate the probe's sensing capabilities for different DNA structures (ssDNA, dsDNA, G4 DNA) under varying potassium ion concentrations.
• To explore the influence of ion atmosphere effects on DNA probe selectivity and design.

Main Methods:

• Facile synthesis of IPQC with high yield (85%).
• UV-vis and fluorescence spectroscopy were employed to monitor DNA binding.
• Testing of IPQC with single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), and G-quadruplex DNA (G4 DNA) at different potassium ion concentrations ([K+]).

Main Results:

• IPQC functions as a universal probe for ssDNA, dsDNA, and G4 DNA in low [K+] (< 20 mM).
• IPQC exhibits highly selective G4 DNA binding in high [K+] (e.g., 150 mM) conditions, evidenced by UV-vis and fluorescence changes.
• Ion atmosphere effects significantly influence probe selectivity, demonstrating a tunable sensing mechanism.

Conclusions:

• The synthesized IPQC probe offers dual-mode sensing capabilities for DNA structures.
• The findings highlight the importance of ion concentration in modulating DNA probe interactions.
• This study provides valuable insights for designing and optimizing DNA probes for targeted disease diagnostics.