Avaliação da biocompatibilidade de simonkolleite dopado com ouro em Drosophila melanogaster

Abstract

Simonkolleite Nanocrystals (SM), resulting from zinc corrosion, have been extensively investigated for their technological applications, such as in supercapacitors. However, their toxicity remains poorly understood. Doping SM with gold has the potential to confer antimicrobial properties, which further emphasizes the need to evaluate their biological safety. In this context, Drosophila melanogaster was employed as an experimental model to investigate the effects of gold-doped SM (1% and 5%) on development, locomotor behavior, and biochemical parameters. Canton S strain larvae were orally exposed to different concentrations of the nanocrystals incorporated into the culture medium (Control; Positive control; 0.015, 0.030, 0.060, and 0.120 mg/mL), with the positive control being the herbicide imazapyr added to the standard medium at 0.15 mg/mL. Pupation rate, larval lethality, and daily pupae count were assessed. Larval motility was analyzed by measuring the distance traveled and average speed using a standardized filming system. Additionally, the activities of the enzymes superoxide dismutase (SOD), catalase, and total thiols (T-SH) were evaluated, along with the quantification of malondialdehyde (MDA), a marker of lipid peroxidation. An adult motility test was also performed, in which 3–5-day-old flies were exposed to the nanocrystals for 24 and 96 hours and subjected to negative geotaxis assays. The results indicated that the tested concentrations of SM, whether doped with gold or not, did not significantly alter developmental parameters, except in the positive control group, which showed higher larval lethality and a lower pupation rate. In the larval motility assay, а significant reduction in the distance traveled and average speed was observed in larvae exposed to gold-doped SM at 1% and 5% at a concentration of 0.120 mg/mL. Abnormal behaviors, such as circular movement, were observed in the positive control and in the group doped with 5% gold at 0.015 mg/mL. Regarding enzymatic activity, no changes were detected in SOD activity or T-SH levels. However, catalase activity increased in the treated groups, and MDA levels were elevated only in the group SM:5%Au at 0.120 mg/mL. In the adult motility tests, only females exposed to the 0.060 mg/mL concentration (5% gold) showed a significant reduction in geotaxis. In conclusion, SM:5%Au may induce behavioral and biochemical toxіс effects in D. melanogaster, particularly at higher concentrations, highlighting the need for further studies to elucidate the underlying mechanisms and ensure their safety for biomedical and technological applications.