LptD-antigen system on gold nanoparticles: an innovative strategy in the nanovaccine development

Abstract

Abstract Nanovaccine development is a growing research field in which the development of new carriers and bioconjugation approaches is a priority. In this sense, this report describes for the first time, the development of a novel conjugate that consists of gold nanoparticles (AuNPs) obtained by a one-step synthesis using an immunogenic peptide of the Lipopolysaccharide-assembly protein LptD from Vibrio parahaemolyticus bacteria as a reducing and capping agent. The resulting LptD@AuNPs compounds were fully characterized and the results showed the high capacity of the peptide to form complexes and reduce gold ions. The reaction yield estimated was higher than 83% and the chemical integrity of the peptide on the NP surface revealed a tyrosine amino acid bonding on the AuNP surface. Furthermore, the LptD@AuNP system showed high colloidal stability in a wide pH range (3–11 pH values), where the hydrodynamic diameter and Zeta potential behavior were strongly influenced by the functional groups of the antigenic peptide. The cytotoxicity assays showed that the obtained system is safe for mouse leukocytes, while immunized mice with LptD@AuNPs produced specific IgG antibodies. These encouraging results revealed the efficacy of some antigenic peptides as reducers and capping agents, in addition, opening the path to determine immunogenicity and immunoprotective efficacy of the LptD@AuNP system against the disease induced by Vibrio parahaemolyticus.