DNA-Chitosan Hydrogels: Formation, Properties, and Functionalization with Catalytic Nanoparticles

Area of Science:

• Materials Science
• Biomaterials Engineering
• Nanotechnology

Background:

• DNA-chitosan (DNA-CS) interpolyelectrolyte complexes (IPEC) offer tunable properties for advanced material applications.
• Controlling the assembly of DNA and chitosan is crucial for developing stable hydrogel structures.

Purpose of the Study:

• To prepare stable DNA-CS hydrogels via a co-assembled regime.
• To investigate the influence of DNA and chitosan ratios on hydrogel properties and metal ion absorption.
• To develop a catalytic system using gold nanoparticles embedded in DNA-CS hydrogels.

Main Methods:

• Preparation of DNA-CS hydrogels through in situ charging of chitosan in a DNA solution.
• Characterization of hydrogel structure, stability, and ion absorption capabilities.
• Entrapment of Au3+ ions and subsequent reduction to form gold nanoparticles within the hydrogel matrix.
• Evaluation of the catalytic activity of metallized hydrogels in nitroaromatic reduction.

Main Results:

• Stable DNA-CS IPEC hydrogels were formed at near-stoichiometric ratios, unlike poorly controlled coacervates.
• Hydrogel properties, including ion absorption, were strongly dependent on the CS/DNA ratio.
• Efficient entrapment of Au3+ ions was achieved due to the high affinity of DNA and CS for gold.
• Formation of ~2-3 nm gold nanoparticles on DNA-CS scaffolds resulted in catalytically active metallized hydrogels.
• Catalytic activity in nitroaromatic reduction varied with the CS/DNA ratio.

Conclusions:

• DNA-CS IPEC hydrogels provide a stable and tunable platform for metal ion absorption and nanoparticle synthesis.
• The developed metallized hydrogels exhibit efficient catalytic activity, with performance modulated by the hydrogel composition.
• This study highlights the potential of DNA-CS hydrogels as versatile materials for catalysis and environmental applications.