Differences of functionalized graphene materials on inducing chronic aquatic toxicity through the regulation of DNA damage, metabolism and oxidative stress in Daphnia magna

• Published in: The Science of the total environment 2023-06, Vol.876, p.162735-162735, Article 162735
• Main Authors: Huang, Yang, Yao, Hongye, Li, Xuehua, Li, Fei, Wang, Xiaoqing, Fu, Zhiqiang, Li, Ningjing, Chen, Jingwen
• Format: Article
• Language: English
• Subjects: Animals; Chronic aquatic toxicity; Daphnia; Daphnia magna; DNA Damage; Graphene; Graphite - toxicity; Nanostructures - toxicity; Oxidative Stress; Surface modification; Transcriptomics; Water Pollutants, Chemical - metabolism
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.162735

Graphene can be modified with functional groups when released into the environment. However, very little is known about molecular mechanisms of chronic aquatic toxicity induced by graphene nanomaterials with different surface functional groups. By using RNA sequencing, we investigated the toxic mechanisms of unfunctionalized graphene (u-G), carboxylated graphene (G-COOH), aminated graphene (G-NH2), hydroxylated graphene (G-OH) and thiolated graphene (G-SH) to Daphnia magna during 21-day exposure. We revealed that alteration of ferritin transcription levels in the “mineral absorption” signaling pathway is a molecular initiating event leading to potential of oxidative stress in Daphnia magna by u-G, while toxic effects of four functionalized graphenes are related to several metabolic pathways including the “protein digestion and absorption” pathway and “carbohydrate digestion and absorption” pathway. The transcription and translation related pathways were inhibited by G-NH2 and G-OH, which further affected the functions of proteins and normal life activities. Noticeably, detoxifications of graphene and its surface functional derivatives were promoted by increasing the gene expressions related to chitin and glucose metabolism as well as cuticle structure components. These findings demonstrate important mechanistic insights that can potentially be employed for safety assessment of graphene nanomaterials. [Display omitted] •Ferritin transcription was a MIE of oxidative stress caused by graphene.•Toxic effects are related to several metabolic pathways such as “protein digestion”.•G-NH2 and G-OH may inhibit transcription and translation and cause DNA damage.•Detoxification was promoted by the expression of chitin metabolism related genes.