Safety and toxicity concerns of graphene and its composites

Abstract

Although graphene has proven to be a potential 2D nanomaterial in various applications especially in the field of biomedicine, it is not without any toxicity. The graphene family nanomaterials (GFNs) comprises diverse materials of which pristine graphene, graphene oxide, reduced graphene oxide, quantum graphene dots are mostly used. The use of these materials in applications of various fields has increased the risk of human exposure which raised the safety and toxicity concerns. The GFNs toxicity is dependent on its physiochemical properties like size, shape, surface charge. The toxicity exerted by GFNs is mediated by several mechanisms which are discussed in this chapter. The important mechanisms involved are by direct physical damage to cell membranes, oxidative stress induced by reactive oxygen species generation and damage to nucleic acids. The entry of GFNs into body through occupational exposure is mediated by various routes like inhalation, ocular, cutaneous and unintentional ingestion. Various in vitro cytotoxicity studies are enlisted which demonstrated the dose dependent toxicity to several cell lines. GFNs have also showed significant cytotoxicity against various strains of bacteria and fungi. GFNs have shown to be get accumulated in various organs like liver, kidney, lungs, spleen and few other which are discussed in this review. The accumulated GFNs show dose and time dependent tissue damage. The functionalization of GFNs with polymers like polyethylene glycol, chitosan, polyvinyl alcohol, etc., tend to improve their biocompatibility, decrease toxicity and enhances their clearance from organs. The studies on functionalized GFNs and potential polymers that can be used in functionalization should be taken as hot area of interest among researchers so that in near future these composites can be used in various applications to eliminate the toxicity imposed by GFNs.