1. Effect of the Nano-Bio Interface on the
Genotoxicity of Titanium Dioxide Nanoparticles
and Associated Cellular Response
Raju Y. Prasad
Ph.D Candidate
Environmental Science and Engineering Department
UNC Gillings’ Global School of Public Health
GPSF University Research Day
February 26, 2012
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2. Brief History of Engineered Nanoparticles
“There’s Plenty of Room at the Bottom” – Richard Feynman, Nobel Laureate Physicist, 1959
1985 – First nanoparticle 2001 – President Clinton Development of
synthesized (carbon establishes National Nanoparticles for:
fullerenes) Nanotechnology Initiative
• Drug Delivery
• Consumer Products
• Industrial Products
“The 2013 Federal Budget provides $1.8 billion for
the National Nanotechnology Initiative (NNI)”
2
3. Definition of Engineered Nanoparticles
~1.6 m ~2 nm width
100 10-1 10-2 10-3 10-6 10-9
1-100 nm
meter decimeter centimeter millimeter micrometer nanometer
Particles with a size dimension between 1 and 100 nm
that show novel properties that are not found in bulk
samples of the same material
3
5. Use of Titanium Dioxide Nanoparticles in Consumer
Products
Sunscreens : ~10-100 µg Ti/mg product (1-10%)
www.consumerreports.org
Weir et al. Environ Sci Technol 2012
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6. Association of Physicochemical Properties with Toxicity
Due to small size dimensions, large surface area to volume
ratio, novel properties, and potential exposure, it is
important to determine effects on human health
Sayes et al. Tox Sci 2006
There is a need to determine physicochemical characteristics of
nanoparticles that can lead to adverse effects
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10. Study Hypothesis
The treatment medium that elicits the smallest
nanoparticle agglomerates will be associated
with cellular interaction and genotoxicity
11. Identification of the Protein Adsorbed to the Surface of the
Nanoparticles
KB DM KF
2
Ti O i n K 2 2
B Ti O i n D Ti O i n K
M F
ladder
kDa
250
130
95
72
55
36
28
Tedja et al., 2012 ACS Nano, Lundqvist et al., 2008 PNAS 11
12. Size Measurements in Treatment Media
0h
KB
24 h DM
KF
Prasad et al., 2013 ACS Nano
12
13. No Significant Cytotoxicity in BEAS-2B cells
0 µg/ml 10 µg/ml 20 µg/ml 50 µg/ml 100 µg/ml MMS (100 µM)
Li ve:
C cei n-
al
AM
D ead:
Pr opi di um
I odi de
Prasad et al., 2013 ACS Nano 13
14. Highest Cellular Uptake in KF Medium Determined by Flow
Cytometry
Flow Cytometry Histograms
Prasad et al., 2013 ACS Nano 14
15. Evaluation of Genotoxicity (Damage to the Genome)
DNA Damage Chromosomal Damage
Binucleated cell
(BN)
treat 24 h 48 h
Add CytoSpin cells
cytochalasin B on glass slides
Micronucleated
Binucleated cell
(MN)
Fenech et al. Mutat Res-Fund Mol M 2000 , Kirsch-Volders et al. Mutat Res-Fund Mol M 2003, Singh et al. Mutat Res 1991 15
18. Increased % of S-Phase Cells in KF Medium
Cell Cycle
Prasad et al., 2013 ACS Nano
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19. Summary
Medium that elicited smallest
agglomerates (KF) was associated
with highest cellular
uptake, micronuclei
formation, and increased % of
cells in S phase.
In contrast, DNA damage was
induced regardless of
agglomeration and cellular
uptake
Inhalation exposure to titanium
dioxide nanoparticles may not
induce micronuclei in lung
cells, whereas, serum proteins in
“blood” (for example, ingestion
exposure) may act to lower
agglomeration and induce
Prasad et al., 2013 ACS Nano
micronuclei formation. 19
20. Thank you
Dr. Rebecca Fry Dr. David DeMarini Dr. Ivan Rusyn Dr. Jim Swenberg Dr. Bill Kaufmann
Kathleen Wallace Dr. Carl Blackman Dr. Nana Nikolaishvili-Feinberg
Kaitlin Daniel Dr. Jorge Muniz Ortiz Dr. Stephanie Cohen
Alan Tennant Dr. Andrew Kligerman Mark Olorvida
Jim Campbell Dr. Robert Zucker Bentley Midkiff
Micaela Killius Dr. Steve Simmons Mervi Eeva
Sharon Leavitt Dr. Kevin Dreher Dr. Stephanie Smith-Roe
Ben Castellon Dr. Bellina Veronesi Lisa Smeester
Jenna Strickland Dr. Brian Chorley Dr. Kathryn Bailey
Danielle Ackerman Dr. Thomas Knudsen Dr. Bhavesh Ahir
Peggy Matthews Dr. Kirk Kitchin Dr. Julia Rager
Sarah Warren Dr. Will Boyes Alison Sanders
Nancy Hanley Dr. Bill Lefew Fry lab
Laura Degn Keith Tarpley
Kristen Sanders U.S. EPA NHEERL
Questions?
