Center for the Environmental Implications of NanoTechnology

Transcription

1 Center for the Environmental Implications of NanoTechnology Mark R. Wiesner Director Duke University

2 Center for the Environmental Implications of NanoTechnology (CEINT) 1. Elucidate general principles that determine environmental behavior of nanomaterials 2. Provide guidance in assessing existing and future concerns 3. 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

3 Research Thrusts Key Areas of Expertise Environmental biology Ecotoxicology Nanomaterial transport & transformation Nano-Biogeochemistry Nanochemistry Risk assessment and societal impact Atmospheric particles

4 Cl - Ca 2+ The nano-ag example nanomaterials ecosystem impacts Nanomaterials Nano-Ag today Ca 2+ Cl - cellular/organismal impacts Risk assessment Cl - Na + CO 3 2- Ca 2+ Transport and transformation of nano-ag nanomaterials

5 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

6 A lifecycle perspective of nano risk Sources Robichaud et. al 2009

7 Source of NM S Intermediate Product I j,i=1 n Nano-Enabled Product P j,j=1 m I 1 P 1 S I 2 P 2 I n P m Air WWTP Storage /Use Landfill Agricultural Land Sludge Effluent Natural Waters Wiesner, Robichaud, Casman ( Duke & CMU)

8 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

9 Estimated Sources Industrial applications of bulk silver Nano-Ag Estimates 14,161 Estimated nano-ag production Current nano-ag as a % of Bulk Market 0.01% - 6% Nano-TiO 2 Upper Bound Estimate Metric Tons/Year Metric Tons/Year Bulk Market TiO 2 1,700,000 Metric Tons/Year Estimated Upper Bound nano-tio 2 Metric 44,400 production Tons/Year Current nano-tio 2 as a % of Bulk ~3% Market Wiesner lab (Christine Robichaud), Duke

10 Cores A & B: Manufactured, Natural and Incidental Nanoparticles Manufactured Incidental Environmental Transformations Natural

11 A Citrate-coated Ag nanoparticle Gum arabic-coated Ag nanoparticle Small PVP-coated Ag nanoparticle 20 nm B nm ,2 100 nm Number weighted 60 1 Volume weighted ζ potential: -33,0 mv Nanoparticles synthesized by Chilkoti lab Number of particles Diameter (nm) ζ potential: -30,8 mv Nanoparticles synthesized by Liu lab Number of particles Frequency 0,8 0,6 0,4 0, Hydrodynamic diameter (nm) Diameter (nm) ζ potential: -22,5 mv Nanoparticles from NanoAmor Liu and Chilkoti labs, Duke

12 Theme 1: Exposure: Transport and Transformation Predict NM behavior from first principles Raw NM Intermediate products Finished Products Disposal and reuse Life Cycle Releases NM Properties Transformations Modified NM Properties Distribution, Concentration, and Effects

13 detector Nanoparticle aggregation and deposition data acquisition porous medium syringe pump gear pump flow measurement feed solution Wiesner lab (Shihong Lin), Duke

14 Affinity of nano-ag for surfaces predictable based on surface composition Wiesner lab (Shihong Lin), Duke

15 Colloidal stability of coated-ag nanoparticles across a salinity gradient 24h 48h PVP-coated nanoparticles Citrate-coated nanoparticles Gum arabic-coated nanoparticles

16 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

17 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.

18 Theme 2: Cellular and organismal responses Drivers of organismal uptake Impacts on organisms Mechanisms of toxicity Population-level effects Generational/ evolutionary impacts

19 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

20 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

21 Earthworms (Eisenia fetida) Bioavailability Bulk ICP-MS analysis Reproductive toxicity Biodistribution- Laser ablation ICP-MS 20 nm Ag exposed E. fetida Changes in gene expression - metallothionein distance y (um) distance x (um) Bertsch lab, University of Kentucky

22 nanoag Uptake Assays with Corbicula fluminea 10 9 Removal of BSA-coated AgNP over time by Corbicula fluminea Errorbars denote 5 error for data se 8 7 [Ag], mg/l ppm 4 ppm Control 8 ppm With clam Without clam Time, hours Vikesland lab, Virginia Tech

23 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

24 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)

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26 Zone of inhibition tests with pure cultures!"#$%&'(#$()$("#$&#*$"'+$'$,&(#-$./+0$("'($1'+./%%#.$/2$3$4567$)8$95:; < =$!"#-#$/+$'$>&#'- -/25$)8$2)$5-)1("$)2$("/+$!"#$%%&'('&)*%$'(%&'(#=!!!!"#!$%%!&#!'(%)*+!,$,&-$.*+($%'!.*'.*/0!&,%1!.2*!345" 6!7&,.+&%!7+*$.*/!$ 8&,*!&#!,&!4+&9.2!&,!!"#$%&'#$,/!("#)*+,&')"

27 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 Blaser, S. A. et al., Science of the Total Environment (2008). Sludge ID (from Midwest region) Elemental Analysis Element (mg kg -1 ) Mg Ag 856 Mn 1070 Al Na 6080 Ca P Cu 1720 Ti 4510 Fe Zn 1530

28 AgNPs identified in wastewater, but unclear if they are manufactured or incidental Counts Counts Energy (kev) Energy (kev) Hochella lab, Virginia Tech

29 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 Ag 2 S. Ag K-edge EXAFS data was analyzed. Synchrotron XRD confirms Ag 2 S. Lowry Lab, Carnegie Mellon

30 AgNP + cysteine. Ag L III -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% Ag- Cys.! 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. AgNP + S-ligands Lowry and Hsu-Kim Labs (CMU and Duke)

31 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

32 Theme 3: Ecosystem-level impacts laboratory mesocosms

33 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)

34 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)

35 Mesocosms Bernhardt, Espinasse, Richardson & Wiesner

36 Nano-Ag: Preliminary (-'2+%)-( ()D/>/(B JD%)+G-#$&/0#&B$/2>&G.#+$H)("$4'2G8'>(G-#.$'2.$/2>/.#2('& +)G->#+

37 Thank You ICEIN 2010 May 11,12,13 UCLA Los Angels, CA