Characterization of MSY Nanodiamonds as a Nanoparticulate Adjuvant for RiVax Vaccine

Abstract

Vaccines are weakened or mutated versions of the pathogens that invoke an immune response through controlled and targeted delivery. Live-attenuated and inactivated vaccines invoke an immediate and protective immune response but have higher risks in a subset of patients. Subunit vaccines are an antigenic part of the pathogen that can be paired with an adjuvant to invoke an effective immune response and cause less adverse reactions. Adjuvants are made of a wide variety of materials that aid in antigenic expression in the body, in hopes of providing protection. Nanodiamonds have a 3D carbon structure that has highly tailorable surface chemistry to provide customization for interaction of antigens that would mimic an effect similar to a virus-like particle. Here, the synthesis of modified nanodiamonds is further developed by chemical modifications into three derivatives: oxidized, acidified, and amine modified nanodiamonds. Each derivative was compositionally and morphologically characterized to understand their stability and binding capacity. The unmodified nanodiamonds were selected to be further characterized but with a vaccine called RiVax. RiVax is a mutated ricin protein that prevents ricin toxicity for up to four months, but greater longevity and immunity is desired. In in vivo release studies, RiVax adsorbed to the unmodified nanodiamonds had recognition of adsorbed ricin and significantly low recognition of soluble ricin, leading to a survival rate of 50% in mice. Overall, nanodiamonds did not improve the RiVax vaccine but has shown respectable alterability, which could be beneficial to other subunit vaccines.