Robust vaccine formulation produced by assembling a hybrid coating of polyethyleneimine-silica.

Exploring formulations that can improve the thermostability and immunogenicity of vaccines holds great promise in advancing the efficacy of vaccination to combat infectious diseases. Inspired by biomineralized core-shell structures in nature, we suggest a polyethyleneimine (PEI)-silica-PEI hybrid coated vaccine formulation to improve both thermostability and immunogenicity. Through electrostatic adsorption, silicification and capping treatment, a hybrid coating of silica and PEI was assembled around a vaccine to produce vaccine@PEI-silica structures. Both and experiments demonstrated that the thermostability and immunogenicity of the modified vaccine were significantly improved. The modified vaccine could be used efficiently after long-term exposure at room temperature, which would facilitate vaccine transport and storage without a cold chain. Furthermore, mechanistic studies revealed that the PEI-silica-PEI coating acted as a physiochemical anchor as well as a mobility-restricting hydration layer to stabilize the enclosed vaccine. This achievement demonstrates a biomimetic surface-modification-based strategy to confer desired properties on biological products.