Zwitterionic Gel Coating Endows Gold Nanoparticles with Ultrastability

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Colloidal stability of gold nanoparticles (GNPs) is crucial for their diverse applications.
• Existing ligand-based protection methods for GNPs can fail under extreme conditions, leading to irreversible aggregation.
• Developing robust stabilization strategies is essential for expanding GNP utility.

Purpose of the Study:

• To develop a novel zwitterionic encapsulation strategy for achieving ultrastability in gold nanoparticles (GNPs).
• To evaluate the efficacy of this strategy in preventing GNP aggregation under harsh environmental conditions.
• To assess the biocompatibility and functionalization potential of the zwitterionic-coated GNPs.

Main Methods:

• Coating individual gold nanoparticles (GNPs) with a cross-linked zwitterionic poly(ornithine methacrylamide) hydrogel thin-layer.
• Testing nanoparticle stability under extreme conditions: lyophilization, strong acid, saturated salt, and concentrated alkali solutions.
• Evaluating protein adsorption resistance in biological milieu, including full human blood serum.
• Assessing the potential for biomolecular functionalization via the amino-acid-derived polymer gel.

Main Results:

• The zwitterionic hydrogel coating effectively prevented gold nanoparticle (GNP) aggregation under all tested harsh conditions.
• The coated GNPs demonstrated resistance to protein adsorption in human blood serum, indicating good biocompatibility.
• The zwitterionic gel layer provides abundant sites for subsequent biomolecular conjugation.
• The developed strategy imparts ultrastability to GNPs, overcoming limitations of previous methods.

Conclusions:

• Zwitterionic encapsulation provides a highly effective strategy for stabilizing gold nanoparticles (GNPs) against aggregation in extreme environments.
• The robust and functionalizable zwitterionic-coated GNPs show significant promise for advanced applications in sensing and theranostics.
• This approach enhances the reliability and expands the application scope of gold nanoparticles in biological and material science fields.