Amino Compound-Synthesized Gold Nanoparticles for SARS-CoV-2 Antigen Delivery.

Area of Science:

• Nanotechnology
• Immunology
• Materials Science

Background:

• Gold nanoparticles (AuNPs) are effective vaccine antigen delivery platforms, with properties influenced by synthesis methods.
• Amino acids are typically capping agents for AuNPs, but their dual role as reducing and stabilizing agents is less explored.
• Optimizing AuNP physicochemical properties is crucial for enhancing immune responses.

Purpose of the Study:

• To develop an ultrasound-assisted synthesis of AuNPs using amino compounds as dual reducing/stabilizing agents.
• To characterize the synthesized AuNPs' physicochemical properties, antigen-binding, and immunogenicity.
• To evaluate AuNPs as antigen delivery vehicles for SARS-CoV-2 vaccines.

Main Methods:

• AuNPs synthesized using L-cysteine, L-arginine, and cysteamine under ultrasonic conditions.
• Nanoparticles characterized for size (6.3–12.4 nm hydrodynamic diameter) and surface charge (-40.5 to +36.5 mV zeta potential).
• AuNPs formulated with SARS-CoV-2 receptor-binding domain (RBD) and tested in mice for immunogenicity.

Main Results:

• All AuNP formulations induced robust anti-RBD IgG responses in mice.
• Significant variation in virus neutralization activity observed across different AuNP formulations.
• AuNP-arginine demonstrated the strongest neutralizing response, suggesting epitope preservation is key.

Conclusions:

• Nanoparticle design is critical for optimizing antigen presentation and vaccine efficacy.
• Amino compound-synthesized AuNPs are effective antigen delivery vehicles.
• This method offers a promising approach for developing next-generation vaccines.