Vaccine is one of the most effective strategies for preventing and controlling infectious diseases and some noninfectious diseases, especially cancers. Adjuvants and carriers have been appropriately added to the vaccine formulation to improve the immunogenicity of the antigen and induce long-lasting immunity. However, there is an urgent need to develop new all-purpose adjuvants because some adjuvants approved for human use have limited functionality. Graphene oxide (GO), widely employed for the delivery of biomolecules, excels in loading and delivering antigen and shows the potentiality of activating the immune system. However, GO aggregates in biological liquid and induces cell death, and it also exhibits poor biosolubility and biocompatibility. To address these limitations, various surface modification protocols have been employed to integrate aqueous compatible substances with GO to effectively improve its biocompatibility. More importantly, these modifications render functionalized-GO with superior properties as both carriers and adjuvants. Herein, the recent progress of physicochemical properties and surface modification strategies of GO for its application as both carriers and adjuvants is reviewed.
Degradation of pristine graphene occurs in the human body when interacting with a naturally occurring enzyme found in the lung, announced Graphene Flagship partners; the French National Centre for Scientific Research (CNRS), University of Strasbourg, Karolinska Institute and University of Castilla–La Mancha (UCLM).
Graphene-based products, including flexible biomedical electronic devices, are being designed for interface with the human body within the Graphene Flagship. If graphene is to be used for such biomedical applications, it should be biodegradable and thus be expelled from the body.
To test how graphene behaves within the body, Alberto Bianco and his team at Graphene Flagship partner CNRS conducted several tests to determine whether and how graphene was broken down with the addition of a common human enzyme. The enzyme, myeloperoxidase (MPO), is a peroxide enzyme released by neutrophils, cells found in the lungs that are responsible for the elimination of foreign bodies or bacteria that enter the body. If a foreign body or bacteria is detected inside of the body, neutrophils surround it and secrete MPO, thereby destroying the threat. Previous work by Graphene Flagship partners found MPO to biodegrade graphene oxide. However the structure of non-functionalized graphene was thought to be more degradation resistant. To test this, Bianco and his team looked at the effects of MPO, ex vivo, on two graphene forms: single- and few-layer.