Fluorescent Silver Nanoclusters Associated with Double-Stranded Poly(dGdC) DNA

Area of Science:

• Biophysics
• Materials Science
• Nanotechnology

Background:

• Double-stranded (ds) DNA, specifically poly(dGdC), has unique structural properties.
• Silver ions (Ag+) are known to interact with nucleic acids, but their effects on long, repetitive ds DNA are not fully understood.

Purpose of the Study:

• To investigate the structural and optical properties of poly(dGdC)-Ag+ conjugates.
• To explore the potential applications of these novel DNA-silver conjugates.

Main Methods:

• Atomic Force Microscopy (AFM) imaging
• Circular Dichroism (CD) spectroscopy
• Quantum Mechanical (QM) and Molecular Mechanics (MMs) calculations

Main Results:

• Binding of Ag+ to poly(dGdC) induces a one-base shift, forming alternating CC and GG base pairs coordinated by silver ions.
• The resulting DNA-silver conjugate exhibits strong fluorescence at 720 nm upon reduction and oxidation of silver.
• QM and MMs calculations support the proposed structure and dynamic behavior of the conjugate.

Conclusions:

• A novel, highly fluorescent DNA-silver conjugate with potential conductive properties has been synthesized.
• The poly(dGdC)-Ag conjugate functions as a dynamic system with embedded silver nanoclusters.
• These conjugates are promising candidates for applications in nanodevices and nanosensors.