TY - JOUR
T1 - Toxicity assessment of manufactured nanomaterials using the unicellular green alga Chlamydomonas reinhardtii
AU - Wang, Jiangxin
AU - Zhang, Xuezhi
AU - Chen, Yongsheng
AU - Sommerfeld, Milton
AU - Hu, Qiang
N1 - Funding Information:
The authors acknowledge the research funding (Grant # RD833327) from the US Environmental Protection Agency, as well as the 90 Plus Particle Size Analyzer provided by Ira A. Fulton School of Engineering at Arizona State University.
PY - 2008/10
Y1 - 2008/10
N2 - With the rapid development of nanotechnology, there is an increasing risk of human and environmental exposure to nanotechnology-based materials and products. As water resources are particularly vulnerable to direct and indirect contamination of nonomaterials (NMs), the potential toxicity and environmental implication of NMs to aquatic organisms must be evaluated. In this study, we assessed potential toxicity of two commercially used NMs, titanium dioxide (TiO2) and quantum dots (QDs), using the unicellular green alga Chlamydomonas reinhartii as a model system. The response of the organism to NMs was assessed at physiological, biochemical, and molecular genetic levels. Growth kinetics showed that growth inhibition occurred during the first two to three days of cultivation in the presence of TiO2 or QDs. Measurements of lipid peroxidation measurement indicated that oxidative stress of the cells occurred as early as 6 h after exposure to TiO2 or QDs. The transcriptional expression profiling of four stress response genes (sod1, gpx, cat, and ptox2) revealed that transient up-regulation of these genes occurred in cultures containing as low as 1.0 mg L-1 of TiO2 or 0.1 mg L-1 of QDs, and the maximum transcripts of cat, sod1, gpx, and ptox2 occurred at 1.5, 3, 3, and 6 h, respectively, and were proportional to the initial concentration of the NMs. As the cultures continued, recovery in growth was observed and the extent of recovery, as indicated by the final cell concentration, was dosage-dependent. QDs were found to be more toxic to Chlamydomonas cells than TiO2 under our experimental conditions.
AB - With the rapid development of nanotechnology, there is an increasing risk of human and environmental exposure to nanotechnology-based materials and products. As water resources are particularly vulnerable to direct and indirect contamination of nonomaterials (NMs), the potential toxicity and environmental implication of NMs to aquatic organisms must be evaluated. In this study, we assessed potential toxicity of two commercially used NMs, titanium dioxide (TiO2) and quantum dots (QDs), using the unicellular green alga Chlamydomonas reinhartii as a model system. The response of the organism to NMs was assessed at physiological, biochemical, and molecular genetic levels. Growth kinetics showed that growth inhibition occurred during the first two to three days of cultivation in the presence of TiO2 or QDs. Measurements of lipid peroxidation measurement indicated that oxidative stress of the cells occurred as early as 6 h after exposure to TiO2 or QDs. The transcriptional expression profiling of four stress response genes (sod1, gpx, cat, and ptox2) revealed that transient up-regulation of these genes occurred in cultures containing as low as 1.0 mg L-1 of TiO2 or 0.1 mg L-1 of QDs, and the maximum transcripts of cat, sod1, gpx, and ptox2 occurred at 1.5, 3, 3, and 6 h, respectively, and were proportional to the initial concentration of the NMs. As the cultures continued, recovery in growth was observed and the extent of recovery, as indicated by the final cell concentration, was dosage-dependent. QDs were found to be more toxic to Chlamydomonas cells than TiO2 under our experimental conditions.
KW - Antioxidant enzyme
KW - Biomarker
KW - Gene expression
KW - Lipid peroxidation
KW - Quantum dots
KW - Titanium dioxide
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U2 - 10.1016/j.chemosphere.2008.07.040
DO - 10.1016/j.chemosphere.2008.07.040
M3 - Article
C2 - 18768203
AN - SCOPUS:53049109036
SN - 0045-6535
VL - 73
SP - 1121
EP - 1128
JO - Chemosphere
JF - Chemosphere
IS - 7
ER -