Center for the Environmental Implications of NanoTechnology - Society of Toxicology · 2015-05-15 · Center for the Environmental Implications of NanoTechnology (CEINT) 1. Elucidate

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