Mineralization of Few-Layer Graphene Made It Bioavailable in Chlamydomonas reinhardtii

Numerous studies have emphasized the toxicity of graphene-based nanomaterials to algae, however, the fundamental behavior and processes of graphene in biological hosts, including its transportation, metabolization, and bioavailability, are still not well understood. As photosynthetic organisms, algae are key contributors to carbon fixation and may play an important role in the fate of graphene. This study investigated the biological fate of C-14-labeled few-layer graphene (C-14-FLG) in Chlamydomonas reinhardtii (C. reinhardtii). The results showed that C-14-FLG was taken up by C. reinhardtii and then translocated into its chloroplast. Metabolomic analysis revealed that C-14-FLG altered the metabolic profiles (including sugar metabolism, fatty acid, and tricarboxylic acid cycle) of C. reinhardtii, which promoted the photosynthesis of C. reinhardtii and then enhanced their growth. More importantly, the internalized C-14-FLG was metabolized into (CO2)-C-14, which was then used to participate in the metabolic processes required for life. Approximately 61.63%, 25.31%, and 13.06% of the total radioactivity (from (CO2)-C-14) was detected in carbohydrates, lipids, and proteins of algae, respectively. Overall, these results reveal the role of algae in the fate of graphene and highlight the potential of available graphene in bringing biological effects to algae, which helps to better assess the environmental risks of graphene.

Automated summary

This study reveals the biological fate of graphene in algae and its potential biological effects, which is important for assessing the environmental risks of graphene.