Fluorescent silver nanoclusters in condensed DNA

Area of Science:

• Nanomaterials Science
• Biophysics
• Computational Chemistry

Background:

• Silver nanoclusters exhibit unique fluorescent properties.
• DNA nanoparticles offer a versatile platform for nanomaterial encapsulation.
• Understanding the interaction between nanoclusters and DNA is crucial for developing new applications.

Purpose of the Study:

• To investigate the formation and fluorescent characteristics of silver nanoclusters within condensed DNA nanoparticles.
• To compare the stability of these nanoclusters in DNA nanoparticles versus linear DNA.
• To elucidate the binding interactions between silver nanoclusters and DNA bases.

Main Methods:

• Formation of fluorescent globular DNA nanoparticles using dsDNA-cluster complexes and polyallylamine.
• Tip-enhanced fluorescence microscopy for analyzing single DNA nanoparticle fluorescence.
• Density functional theory (DFT) calculations to model nanocluster-DNA binding.

Main Results:

• Condensed DNA nanoparticles effectively encapsulate fluorescent silver nanoclusters.
• Encapsulated clusters demonstrate improved protection against photodamage in solution.
• Identical emission bands (590 and 680 nm) and formation efficiency were observed for clusters on both dsDNA and ssDNA.
• DFT calculations indicate similar binding affinities of nanoclusters to Watson-Crick guanine-cytosine base pairs and single DNA bases.

Conclusions:

• Condensed DNA nanoparticles provide a protective environment for fluorescent silver nanoclusters.
• The binding sites for silver nanoclusters on DNA are consistent across different DNA structures.
• Silver nanoclusters show comparable affinity for both base pairs and single DNA bases, suggesting versatile binding modes.