Separation of Bacteria, Protozoa and Carbon Nanotubes by Density Gradient Centrifugation
- Univ. of California, Santa Barbara, CA (United States). Bren School of Environmental Science and Management, Earth Research Inst., and Center for the Environmental Implications of Nanotechnology; National Institute of Chemical Physics and Biophysics, Tallinn (Estonia). Lab. of Environmental Toxicology
- National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). Biosystems and Biomaterials Division, Material Measurement Lab.
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Univ. of California, Santa Barbara, CA (United States). Bren School of Environmental Science and Management, Earth Research Inst., and Center for the Environmental Implications of Nanotechnology
Sustainable production and use of carbon nanotube (CNT)-enabled materials require efficient assessment of CNT environmental hazards, including the potential for CNT bioaccumulation and biomagnification in environmental receptors. Microbes, as abundant organisms responsible for nutrient cycling in soil and water, are important ecological receptors for studying the effects of CNTs. Quantification of CNT association with microbial cells requires efficient separation of CNT-associated cells from individually dispersed CNTs and CNT agglomerates. Here in this paper, we designed, optimized, and demonstrated procedures for separating bacteria (Pseudomonas aeruginosa) from unbound multiwall carbon nanotubes (MWCNTs) and MWCNT agglomerates using sucrose density gradient centrifugation. We demonstrate separation of protozoa (Tetrahymena thermophila) from MWCNTs, bacterial agglomerates, and protozoan fecal pellets by centrifugation in an iodixanol solution. The presence of MWCNTs in the density gradients after centrifugation was determined by quantification of 14C-labeled MWCNTs; the recovery of microbes from the density gradient media was confirmed by optical microscopy. Protozoan intracellular contents of MWCNTs and of bacteria were also unaffected by the designed separation process. Lastly, the optimized methods contribute to improved efficiency and accuracy in quantifying MWCNT association with bacteria and MWCNT accumulation in protozoan cells, thus supporting improved assessment of CNT bioaccumulation.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE: National Science Foundation (NSF); USEPA; Estonian Research Council
- Grant/Contract Number:
- AC52-07NA27344; PUTJD16
- OSTI ID:
- 1377787
- Report Number(s):
- LLNL-JRNL-684658; NANOKO; PII: nano6100181
- Journal Information:
- Nanomaterials, Vol. 6, Issue 10; ISSN 2079-4991
- Publisher:
- MDPICopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Challenges in characterizing the environmental fate and effects of carbon nanotubes and inorganic nanomaterials in aquatic systems
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journal | January 2018 |
Strategies for robust and accurate experimental approaches to quantify nanomaterial bioaccumulation across a broad range of organisms
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journal | January 2019 |
Challenges in characterizing the environmental fate and effects of carbon nanotubes and inorganic nanomaterials in aquatic systems
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text | January 2018 |
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54 ENVIRONMENTAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS
59 BASIC BIOLOGICAL SCIENCES
37 INORGANIC
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PHYSICAL AND ANALYTICAL CHEMISTRY
Pseudomonas aeruginosa
Tetrahymena thermophila
carbon-14
sucrose
iodixanol
bioaccumulation
bioconcentration
Stokes' law