Mitigation of the impact of single-walled carbon nanotubes on a freshwater green algae: Pseudokirchneriella subcapitata

Abstract

This study investigates the biological response of Pseudokirchneriella subcapitata to single-walled carbon nanotubes (SWNTs) suspended in gum Arabic (GA), using typical 96-hour algal bioassays and long-term growth studies. Changes in algal biomass and cell morphology associated with specific SWNT-treatments were monitored and the mechanisms of observed biological responses investigated through a combination of biochemical and spectroscopic methods. Results from short-term bioassays showed a growth inhibition in culture media containing >0.5 mg SWNT/L and a final GA concentration of 0.023% (v/v). Interestingly, the observed toxicity disappears when GA concentrations are brought to levels ≥ 0.046%. Long-term experiments based on toxic combination of SWNTs and GA showed that P. subcapitata would easily recover from an initial growth inhibition effect. Overall, these findings point to the possibility of GA to mitigate the toxicity of SWNTs, making it an ideal surfactant if SWNT suspension in GA does not alter the performance sought from these nanotubes.

Keywords::

• Single-walled carbon nanotubes
• gum Arabic
• Pseudokirchneriella subcapitata
• exposure
• biological response
• mechanisms

Acknowledgments

We thank Dr Yiider Tseng for access to the ultracentrifugation equipment and Veronica Llaneza for help with toxicity experiments.

Declaration of interest: This research was supported by the USEPA STAR program, grant # RD 83263501, and NSF # CBET-0853347. The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.