Vaccine adjuvants

An overall positively charged vaccine adjuvant, comprising a core of alpha-D-glucan of at least 5% branch density and a plurality of binding moieties covalently bound to the core through hydroxyl groups on the core, wherein the plurality of binding moieties comprises hydrophobic groups and positively charged groups, wherein the molar ratio of positively charged groups versus hydrophobic groups is about 3:2, about 2:1, about 3:1, about 4:1, or about 5:1, the positively charged groups comprise ammonium ions or quaternary ammonium groups rendering the vaccine adjuvant positively charged in the pH range of 3 to 11, and the vaccine adjuvant ranges in size between 10 nanometers and 300 nanometers, and wherein the adjuvant is configured to adsorb negatively charged immunostimulatory molecules and to resist aggregation of the adjuvant nanoparticles.