Occupational exposure to graphene based nanomaterials: risk assessment

Abstract

Graphene-based materials (GBMs) are a family of novel materials including graphene, few layer graphene (FLG), graphene oxide (GO), reduced graphene oxide (rGO) and graphene nanoplatelets (GNP). Currently, the risk posed by them to human health is associated mainly with the occupational exposure during their industrial and small-scale production or waste discharge. The most significant occupational exposure routes are inhalation, oral, cutaneous and ocular, inhalation being the majorly involved and most studied one. This manuscript presents a critical up-to-date review of the available in vivo toxicity data of the most significant GBMs, after using these exposure routes. The few in vivo inhalation toxicity studies (limited to 5-days of repeated exposure and only one to 5 days per week for 4 weeks) indicate inflammatory/fibrotic effects at the pulmonary level, not always reversible after 14/90 days. More limited in vivo data are available for the oral and ocular exposure routes, whereas the studies on cutaneous toxicity are at the initial stage. A long persistence of GBMs in rodents is recorded, while contradictory genotoxic data are reported. Data gap identification is also provided. Based on the available data, the occupational exposure limit cannot be determined. More experimental toxicity studies according to specific guidelines (tentatively validated for nanomaterials) and more information on the actual occupational exposure level to GBMs are needed. Furthermore, ADME (Absorption, Distribution, Metabolism, Excretion), genotoxicity, developmental and reproductive toxicity data related to the occupational exposure to GBMs have to be implemented. In addition, sub-chronic and/or chronic studies are still needed to completely exclude other toxic effects and/or carcinogenicity.

Interactions of graphene oxide and graphene nanoplatelets with the in vitro Caco-2/HT29 model of intestinal barrier

“…In humans, exposure to graphene-based nanomaterials seems to take place mainly at work sites, and it occurs via inhalation, ingestion, cutaneous or ocular exposure. Few in vivo studies have been conducted to determine the risk of such types of exposures, so those using ingestion are scarce 2 . In the mouse model, when mothers and offspring were exposed to GO via drinking water, developmental changes were observed in the offspring.…”

Graphene Nanostructure-Based Tactile Sensors for Electronic Skin Applications

“…Reduced GO (RGO) not only is decorated with multiple oxygen-containing functional groups but also restores the good electronic, thermal, and mechanical properties of graphene. Therefore, abundant organic synthesis principles can be employed with functional supramolecular nanoassemblies of π-conjugated molecules to realize a responsiveness to various stimuli, confirming graphene materials to be excellent scaffolds for various sensors [25][26][27][28][29][30].…”

Skin irritation potential of graphene-based materials using a non-animal test

“…5 In this scenario, the cutaneous and inhalation exposures represent the main human routes involved. 6 However, as compared to other GBM exposure routes, the cutaneous one is largely unexplored. 7 In this view, we recently provided in vitro data on the effects of different GBMs (FLG and GO) towards human HaCaT skin keratinocytes.…”

“…5 Actually, during GBM industrial or laboratory scale production, skin may be considered as one of the main involved exposure routes, after inhalation. 6,7 Moreover, it has to be considered that around 90% of skin diseases related to the occupational settings are represented by irritant and allergic contact dermatitis. 8 However, despite the importance of skin exposure and the dermotoxic potential of GBMs, very limited data on the cutaneous toxicity of these materials are currently available.…”