Amphiphilic polyanhydride nanoparticles stabilize Bacillus anthracis protective antigen.

Area of Science:

• Vaccinology
• Materials Science
• Biotechnology

Background:

• Anthrax vaccines typically use protective antigen (PA) adsorbed to aluminum hydroxide.
• The labile nature of PA poses significant challenges to vaccine stability and efficacy.
• A robust delivery system is needed to maintain PA immunogenicity throughout vaccine production and use.

Purpose of the Study:

• To evaluate biodegradable amphiphilic polyanhydride nanoparticles as a delivery system for stabilizing functional protective antigen (PA).
• To assess the impact of polymer hydrophobicity on PA stability and release from nanoparticles.
• To demonstrate the potential of these nanoparticles for improved anthrax vaccine formulation.

Main Methods:

• Fabrication of biodegradable amphiphilic polyanhydride nanoparticles using specific monomers.
• Encapsulation of protective antigen (PA) within the nanoparticles.
• Evaluation of PA stability and biological function after encapsulation, storage (including elevated temperatures), and release.
• Assessment of polymer hydrophobicity's role in antigen preservation.

Main Results:

• Amphiphilic polyanhydride nanoparticles successfully stabilized and released functional PA.
• Nanoparticle polymer hydrophobicity was critical for preserving PA's biological function.
• Optimal PA preservation was achieved with nanoparticles composed of 1,6-bis(p-carboxyphenoxy)hexane and 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane.
• The delivery system demonstrated stability over extended storage periods and elevated temperatures.

Conclusions:

• Biodegradable amphiphilic polyanhydride nanoparticles offer a superior method for stabilizing protective antigen (PA).
• These nanoparticles provide controlled antigen delivery, enhance antigen stability, and maintain immunogenicity.
• The developed system shows significant promise for creating stable, long-lasting anthrax vaccines.