CEINT overview_nanoAg-LONG

Center for the Environmental
Implications of NanoTechnology
www.ceint.duke.edu
Mark R. Wiesner
Director
Duke University
Center for the Environmental Implications of
NanoTechnology (CEINT)
1.
2.
3.
Elucidate general principles that determine environmental behavior of
nanomaterials
Provide guidance in assessing existing and future concerns
Educate students and the general public regarding nanotechnology, nanoscale
science, and the environment
 4 Core Institutions: Duke (headquarters), CMU, Howard,
Virginia Tech + U Kentucky, Stanford
 Collaborating US government entities (NIST, DOE, EPA, DoD)
 ICEINT- French consortium supported by CNRS and CEA
 10 additional international partners
Research Thrusts
Key Areas of Expertise
 Environmental biology
 Ecotoxicology
 Nanomaterial transport &
transformation
 Nano-Biogeochemistry
 Nanochemistry
 Risk assessment and
societal impact
 Atmospheric particles
The nano-Ag example
nanomaterials
Ca2+
Nanomaterials
Cl-
ecosystem
impacts
Ca2+
cellular/organismal
impacts
ClCa2+
Cl-
Na+
CO3 2-
Transport and
transformation of
nano-Ag
nanomaterials
Nano-Ag
today
Risk assessment
Core C: Risk Assessment & Modeling
How does one do risk assessment with the pervasive
high levels of uncertainty?
Modeling Nano-risk Using
Probability Networks
Reckhow lab (Eric Money), Duke
A lifecycle perspective of nano risk
Sources
Robichaud et. al 2009
Intermediate Product
Ij,i=1n
Source of NM
S
S
Air
I1
P1
I2
P2
In
Pm
WWTP
Sludge
Nano-Enabled Product
Pj,j=1m
Storage
/Use
Landfill
Effluent
Agricultural
Land
Wiesner, Robichaud, Casman ( Duke & CMU)
Natural
Waters
Upper bound production estimation
Intercept: how much is out there now?
Slope: how fast will this amount grow?
Nano-Ag (MT/yr)
– Predicting trends
• Biotech rates
• Patent and research article data
– Current productions
– Company data extrapolation
time
Wiesner lab (Christine Robichaud), Duke
Estimated Sources
Nano-Ag Estimates
Industrial applications of bulk
silver
14,161
Estimated nano-Ag production
0.1 - 800
Current nano-Ag as a % of Bulk
Market
Metric
Tons/Year
Metric
Tons/Year
0.01% - 6%
Nano-TiO2 Upper Bound Estimate
Bulk Market TiO2
Estimated Upper Bound nano-TiO2
production
Current nano-TiO2 as a % of Bulk
Market
Wiesner lab (Christine Robichaud), Duke
1,700,000
44,400
~3%
Metric
Tons/Year
Metric
Tons/Year
Cores A & B: Manufactured, Natural and Incidental
Nanoparticles
Incidental
Manufactured
Environmental
Transformations
Natural
A
Citrate-coated
Ag nanoparticle
Gum arabic-coated
Ag nanoparticle
20 nm
Small PVP-coated
Ag nanoparticle
100 nm
50 nm
80
30
B
70
1,2
25
Number weighted
15
10
0,8
Frequency
Number of particles
Number of particles
60
20
Volume weighted
1
50
40
0,6
0,4
0,2
30
0
10
20
5
ζ potential:
-33,0 mV
ζ potential:
-30,8 mV
0
5
10
15
20
25
30
35
40
45
50
Diameter (nm)
Liu and Chilkoti labs, Duke
1000
ζ potential:
-22,5 mV
10
0
0
Nanoparticles synthesized by Chilkoti lab
100
Hydrodynamic diameter (nm)
Nanoparticles synthesized by Liu lab
0
20
40
60
80
100 120 140 160 180 200
Diameter (nm)
Nanoparticles from NanoAmor
Theme 1: Exposure: Transport and Transformation
Predict NM behavior from first principles
Finished Products
Raw NM
Intermediate
products
Disposal
and reuse
Releases
NM Properties
Transformations
Modified NM
Properties
Distribution, Concentration, and Effects
Life Cycle
Nanoparticle aggregation and
deposition
detector
data acquisition
porous medium
syringe pump
gear pump
flow measurement
feed solution
Wiesner lab (Shihong Lin), Duke
Affinity of nano-Ag for surfaces predictable based
on surface composition
Wiesner lab (Shihong Lin), Duke
Colloidal stability of coated-Ag nanoparticles
across a salinity gradient
24h
48h
PVP-coated
nanoparticles
Citrate-coated
nanoparticles
Gum arabic-coated
nanoparticles
Effect of Sunlight on the Stability of Nano Ag
-coated by gum arabic (GA)
GA coated Ag NPs were precipitated out both under UV light and sunlight
Stable both under heat (60 °C) and room condition (visible light)
No concentration dependence
Liu Lab, Duke
(A) initial and (B) 7 days of sunlight
irradiated PVP coated Ag NPs;
(C) initial and (D) 3 days of sunlight
irradiated of GA coated Ag NPs.
Liu Lab, Duke
Theme 2: Cellular and organismal responses
Drivers of organismal uptake
Impacts on organisms
Mechanisms of toxicity
Population-level effects
Generational/ evolutionary impacts
Toxicity of Ag-NP (PVP and Citrate) and Ag ions in C. elegans
and
- Mortality expected
due to dissolved Ag ions at
maximum concentrations of
PVP and Citrate Ag-NP
Bertsch lab, University of Kentucky
Growth inhibition of C. elegans as a
sublethal toxic effect
25 mg/L
Protocol
expose mutans and
wild strains of C.
elegans to nano Ag
measure
size
• Dose-response effects
• Different toxic mechanisms
as function of the coating
Meyer lab, Duke
Earthworms (Eisenia fetida)
Bioavailability –Bulk ICP-MS analysis
Reproductive toxicity
Biodistribution- Laser ablation – ICP-MS
20 nm Ag exposed E. fetida
0
100
200
300
400
500
600
700
1400
1200
1000
800
600
distance y (um)
400
200
0
500
1000
1500
2000
distance x (um)
Bertsch lab, University of Kentucky
Changes in gene expression metallothionein
nanoAg Uptake Assays with
Corbicula fluminea
Absorbance max of 40nm BSA-AgNP over time
presentover time by
withC. fluminea AgNP
Removal of BSA-coated
10
E r r o rbars denote 5%
Corbicula fluminea
error for data series
9
8
[Ag], mg/L
7
8 ppm
ppm
6
avg8ppm with Clam
5
avg4ppm with Clam
4
2 ppm
ppm
3
avg2ppm with Clam
4 ppm
ppm
avgEPA Water with
ClamWith
2
clam
1
Control
0
0
50
100
Time,hours
hours
Time,
Vikesland lab, Virginia Tech
150
Without
clam
Fish Embryotoxicity across a Salinity Gradient – Particle Size
versus Silver Speciation
Atlan&c Killifish
Fundulus heteroclitus
Colloidal stability
PVP-coated
Citrate-coated
Gum arabic
Di Giulio and Wiesner labs (Cole Matson, Mélanie Auffan), Duke/CEREGE
PVP Coated Nanosilver Kills E. coli
After a 1:20,000 dilution prior to lawning out on a plate and incubating at 37C overnight:
Meyer lab (duke)
Zone of inhibition tests with pure cultures
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Understanding AgNPs formation/ transformation
in wastewater treatment
Targeted National Sewage sludge Survey
Statistical Analysis Report
(Released in Jan 2009)
! 74 plants across the States
! Total metal contents
! Pharmaceuticals, steroids, and hormones
Sludge ID 68349 (from Midwest region)
Elemental Analysis
Blaser, S. A. et al., Science of the Total Environment (2008).
Element
(mg kg-1)
Mg
13500
Ag
856
Mn
1070
Al
57300
Na
6080
Ca
98900
P
57200
Cu
1720
Ti
4510
Fe
51000
Zn
1530
AgNPs identified in wastewater, but unclear if
they are manufactured or incidental
1
2
3
1
Counts
Counts
2
Energy
(keV)
Hochella lab, Virginia Tech
Energy
(keV)
3
Synchrotron XAS and XRD of AgNP Exposed to Oxidizing Conditions: Ag K-edge
• AgNP + excess DO did
not significantly change
the particle.
• AgNP + sulfide
immediately formed Ag2S.
• Ag K-edge EXAFS data
was analyzed.
• Synchrotron XRD
confirms Ag2S.
Lowry Lab, Carnegie Mellon
AgNP + S-ligands
AgNP + cysteine.
Ag LIII-edge XANES and S K-edge EXAFS.
!
Elucidate the oxidation transformation
and the nature of the Ag-S bonds for
both Ag and S.
Preliminary Results:
!
!
Ag XANES LCF: Particles retain ~85%
original AgNP character and ~15% AgCys.
S: Spectra may show the presence of
Cystine (the oxidized form of Cysteine).
Future work (collaborative):
!
!
!
AgNP + other S-ligands, S-containing
environmental materials.
Expand model compound library.
Repeat at the Ag K-edge.
Lowry and Hsu-Kim Labs (CMU and Duke)
Nano-Ag inhibition of bacteria in activated
sludge
higher concentrations of silver inhibited growth by approximately
50%.
Preliminary DGGE results indicate shift in 16S bacterial
communities and overall decrease in the number of communities
as silver concentration increased.
Gunsch lab (Christina Arnaout), Duke
Theme 3: Ecosystem-level impacts
laboratory
mesocosms
Microcosms- Sediments
More complex systems of sediment and surface water
Within 7 days – similar to controls
No clear effects of ionic
or nanosilver on nutrient
availability or enzyme activity
Bernhardt and Richardson labs (Ben Coleman, Duke)
Stream water
No respiration in ionic silver
Repression of respiration at 75mg
Ag/L with AgNP
Decrease in microbial biomass with ionic
silver
Bernhardt and Richardson labs (Ben Coleman, Duke)
Mesocosms
Bernhardt, Espinasse, Richardson & Wiesner
Nano-Ag: Preliminary Conclusions
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Thank You
ICEIN 2010
May 11,12,13
UCLA
Los Angels, CA
www.ceint.duke.edu