Center for the Environmental Implications of NanoTechnology Mark R. Wiesner Director Duke University www.ceint.duke.edu
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Center for the EnvironmentalImplications of NanoTechnology
Mark R. WiesnerDirector
Duke University
www.ceint.duke.edu
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
Center for the Environmental Implications ofNanoTechnology (CEINT)
1. Elucidate general principles that determine environmental behavior ofnanomaterials
2. Provide guidance in assessing existing and future concerns3. Educate students and the general public regarding nanotechnology, nanoscale
science, and the environment
Research Thrusts
Environmental biology Ecotoxicology Nanomaterial transport &
transformation Nano-Biogeochemistry Nanochemistry Risk assessment and
societal impact Atmospheric particles
Key Areas of Expertise
The nano-Ag example
ecosystemimpacts
cellular/organismalimpacts
Transport andtransformation of
nano-Ag
nanomaterials
nanomaterials
Ca2+
Na+CO3
2-
Cl-
Ca2+
Cl-
Ca2+
Cl-
Risk assessment
Nanomaterials
Nano-Agtoday
Core C: Risk Assessment & ModelingHow does one do risk assessment with the pervasivehigh levels of uncertainty?
Reckhow lab (Eric Money), Duke
Modeling Nano-risk UsingModeling Nano-risk UsingProbability NetworksProbability Networks
A lifecycle perspective of nano risk
Sources
Robichaud et. al 2009
S
Air WWTP Storage/Use
Landfill
I1
I2
In
P1
P2
Pm
Source of NMS
Intermediate ProductIj,i=1n
Nano-Enabled ProductPj,j=1m
Sludge EffluentAgricultural
LandNaturalWaters
Wiesner, Robichaud, Casman ( Duke & CMU)
Upper bound production estimation
Intercept: how much is out there now?Slope: how fast will this amount grow?
– Current productions– Company data extrapolation
– Predicting trends• Biotech rates• Patent and research article data
time
Nano-Ag (MT/yr)
Wiesner lab (Christine Robichaud), Duke
Estimated Sources
Nano-Ag EstimatesIndustrial applications of bulksilver
14,161MetricTons/Year
Estimated nano-Ag production 0.1 - 800MetricTons/Year
Current nano-Ag as a % of BulkMarket
0.01% - 6%
Nano-TiO2 Upper Bound Estimate
Bulk Market TiO2 1,700,000MetricTons/Year
Estimated Upper Bound nano-TiO2production
44,400MetricTons/Year
Current nano-TiO2 as a % of BulkMarket
~3%
Wiesner lab (Christine Robichaud), Duke
Cores A & B: Manufactured, Natural and IncidentalNanoparticles
Incidental
Natural
EnvironmentalTransformations
Manufactured
A
B
20 nm
ζ potential:-33,0 mV
Nanoparticles synthesized by Chilkoti lab
Citrate-coatedAg nanoparticle
Gum arabic-coatedAg nanoparticle
50 nm
Nanoparticles synthesized by Liu lab
Liu and Chilkoti labs, Duke
0
5
10
15
20
25
30
0 5 10 15 20 25 30 35 40 45 50
Num
ber o
f par
ticle
s
Diameter (nm)
ζ potential:-30,8 mV
0
10
20
30
40
50
60
70
80
0 20 40 60 80 100 120 140 160 180 200
Num
ber o
f par
ticle
s
Diameter (nm)
100 nm
10 100 1000
Number weighted
Volume weighted
0
0,2
0,4
0,6
0,8
1
1,2
Hydrodynamic diameter (nm)
Freq
uenc
y
ζ potential:-22,5 mV
Nanoparticles from NanoAmor
Small PVP-coatedAg nanoparticle
Theme 1: Exposure: Transport and Transformation
Predict NM behavior from first principles
NM Properties TransformationsModified NMProperties
Distribution, Concentration, and Effects
Releases
Life Cycle Raw NM Intermediateproducts
Finished ProductsDisposaland reuse
Nanoparticle aggregation anddeposition
detector
data acquisition
gear pump
feed solution
syringe pump
flow measurement
porous medium
Wiesner lab (Shihong Lin), Duke
Affinity of nano-Ag for surfaces predictable basedon surface composition
Wiesner lab (Shihong Lin), Duke
Colloidal stability of coated-Ag nanoparticlesacross a salinity gradient
24h48h
Gum arabic-coatednanoparticles
Citrate-coatednanoparticles
PVP-coatednanoparticles
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 sunlightStable 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 expecteddue to dissolved Ag ions atmaximum concentrations ofPVP and Citrate Ag-NP
Bertsch lab, University of Kentucky
Growth inhibition of C. elegans as asublethal toxic effect
Protocolexpose mutans and
wild strains of C.elegans to nano Ag
measure size
Meyer lab, Duke
25 mg/L
• Dose-response effects• Different toxic mechanismsas function of the coating
Earthworms (Eisenia fetida)Bioavailability –Bulk ICP-MS analysis
Biodistribution- Laser ablation – ICP-MS
Changes in gene expression -metallothionein
20 nm Ag exposed E. fetida
distance x (um)
500 1000 1500 2000
distance y (um)
0
200
400
600
800
1000
1200
14000 100 200 300 400 500 600 700
Reproductive toxicity
Bertsch lab, University of Kentucky
Absorbance max of 40nm BSA-AgNP over time with C. fluminea present
0
1
2
3
4
5
6
7
8
9
10
0 50 100 150
Time, hours
[Ag]
, m
g/L
avg8ppm with Clam
avg4ppm with Clam
avg2ppm with Clam
avgEPA Water withClam
Error bars denote 5% error for data series
nanoAg Uptake Assays withCorbicula fluminea
Withclam
Withoutclam
Vikesland lab, Virginia Tech
Time, hours
8 8 ppmppm
4 4 ppmppm
ControlControl
2 2 ppmppm
Removal of BSA-coated AgNP over time byCorbicula fluminea
Fish Embryotoxicity across a Salinity Gradient – Particle Sizeversus Silver Speciation
Atlan&c KillifishFundulus heteroclitus
Di Giulio and Wiesner labs (Cole Matson, Mélanie Auffan), Duke/CEREGE
Colloidal stability
Gum arabic
Citrate-coatedPVP-coated
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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!"#$%&'(#$()$("#$&#*$"'+$'$,&(#-$./+0$("'($1'+./%%#.$/2$3$4567$)8$95:;<=$!"#-#$/+$'$>&#'--/25$)8$2)$5-)1("$)2$("/+$!"#$%%&'('&)*%$'(%&'(#=
Understanding AgNPs formation/ transformationin wastewater treatment
Sludge ID 68349 (from Midwest region)Elemental Analysis
Element (mg kg-1) Mg 13500Ag 856 Mn 1070Al 57300 Na 6080Ca 98900 P 57200Cu 1720 Ti 4510Fe 51000 Zn 1530
Blaser, S. A. et al., Science of the Total Environment (2008).
Targeted National Sewage sludge SurveyStatistical Analysis Report
(Released in Jan 2009)! 74 plants across the States! Total metal contents ! Pharmaceuticals, steroids, and hormones
AgNPs identified in wastewater, but unclear ifthey are manufactured or incidental
12 3
Energy(keV)
Cou
nts
1
Energy(keV)
Cou
nts
2 3
Hochella lab, Virginia Tech
Synchrotron XAS and XRD of AgNP Exposed to Oxidizing Conditions: Ag K-edge
• AgNP + excess DO didnot significantly changethe particle.
• AgNP + sulfideimmediately formed Ag2S.
• Ag K-edge EXAFS datawas analyzed.
• Synchrotron XRDconfirms Ag2S.
Lowry Lab, Carnegie Mellon
AgNP + S-ligandsAgNP + cysteine.Ag LIII-edge XANES and S K-edge EXAFS.
! Elucidate the oxidation transformationand the nature of the Ag-S bonds forboth Ag and S.
Preliminary Results:! Ag XANES LCF: Particles retain ~85%
original AgNP character and ~15% Ag-Cys.
! S: Spectra may show the presence ofCystine (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 activatedsludge
higher concentrations of silver inhibited growth by approximately50%.
Preliminary DGGE results indicate shift in 16S bacterialcommunities and overall decrease in the number of communitiesas silver concentration increased.
Gunsch lab (Christina Arnaout), Duke
Theme 3: Ecosystem-level impacts
mesocosmslaboratory
Microcosms- SedimentsMore complex systems of sediment and surface water
Within 7 days – similar to controls
No clear effects of ionicor nanosilver on nutrientavailability or enzyme activity
Bernhardt and Richardson labs (Ben Coleman, Duke)
No respiration in ionic silverRepression of respiration at 75mgAg/L with AgNP
Decrease in microbial biomass with ionicsilver
Stream water
Bernhardt and Richardson labs (Ben Coleman, Duke)
Mesocosms
Bernhardt, Espinasse, Richardson & Wiesner
Nano-Ag: Preliminary Conclusions•?)'@25+$>"'25#$#A#-B("/25C
•(-'2+%)-(•(-'2+8)-4'@)2•()D/>/(B
•$9../@A#$'E2/(B$)8$2'2)F95$8)-$+G-8'>#+$+G>"$'+$/-)2F)D/.#
•:'2)F95$()D/>/(BC$H)("$./++)&A#.$'2.$2'2)%'-@>&#F+%#>/,>#I#>(+F$>)'@25$>)2(-)&$("#$H'&'2>#
•?)4%&#D$#2A/-)24#2(+$>)2('/2$H)("$4/@5'@25$'2.#D'>#-H'@25$8'>()-+
•JD%)+G-#$&/0#&B$/2>&G.#+$H)("$4'2G8'>(G-#.$'2.$/2>/.#2('&+)G->#+
Thank You
ICEIN 2010May 11,12,13
UCLALos Angels, CA
www.ceint.duke.edu
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