Bioconjugation of Hepatitis B antigenic peptide with polymeric carriers through various carbodiimide chemistry

Abstract

Aim: The purpose of improving function-specific bioconjugates using polyacrylic acid (PAA), the 95-109 amino acid series of Hepititis B surface antigen epitopes, and different polyelectrolytes such as Poly (vinyl pyrrolidone-co-acrylic acid) (VPAA) copolymer is to increase the immunogenity of the antigen peptide. The aim of this study is to use the bioconjugates, obtained from the said conjugation reactions, as models in order to improve new generation vaccinations. Methods: The bioconjugates were synthesized using a water soluble carbodiimide 1-ethyl-3(3-dimethylaminopropyl) carbodiimide via different carboxyl activation mechanisms. After choosing the most effective conjugation method, two different polyelectrolytes, and initial molar ratios were used in conjugation reactions to show the efficiency of the method. In addition, the synthesized bioconjugates were analyzed using Size Exclusion Chromatography and Fluorescence Spectrometer. Results: Chromatographic analyses showed that the best coupling method between Polyelectrolytes and the peptide molecule was Method 3, and the bioconjugation reactions using this method proved that when the peptide concentration increases, the peptide molecule directly binds with polyelectrolytes, and the molecular weight of the resultant bioconjugates increases proportionally as shown in the chromatograms. Conclusion: The chosen activation method provides a strong covalent bond between the peptide and polyelectrolyte molecules, and approaches developed to modify the immunogenecity of antigens opens perspectives for creating new vaccines, diagnostic, pharmaceutical, and biotechnological preparations.