Harvard-NIEHS Center overview: Cores and Activities Philip - - PowerPoint PPT Presentation

Harvard-NIEHS Center overview: Cores and Activities

Philip Demokritou, Center Director

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Collaborating Institutions

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Our Center builds upon the infrastructure and interdisciplinary experience of five existing academic research centers/Institutes in the fields of nanomaterial synthesis, characterization, nanobiology and nanotoxicology research:

• Center for Nanotechnology and Nanotoxicology at Harvard School of

Public Health; (Dr Demokritou)

• Center for Nanoscale Systems (CNS) at Harvard School of Engineering

and Applied Sciences; (Dr Bell)

• Laboratory for Advanced Carbon-based Nanomaterials at MIT; (Dr

Strano)

• Particle Engineering Research Center (PERC) at University of Florida; (Dr

Moudgil)

• Forest Bio-products Research Institute at University of Maine. (Dr

Bousfield)

Our mission statement

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 We will work across disciplines, share new ideas, develop industry- relevant reference ENMs, and work with the nanotox consortium to develop multidisciplinary projects and methods to advance our understanding on nano-safety.

• Where Applications of Engineered Nanomaterials and

Nanotechnology meet Nanosafety research

– Vision: Integrate material & exposure science and nanotoxicology risk assessment to pave the way towards sustainable nanotechnology – Research Areas: Environmental nanotechnology, safer by design synthesis of ENMs, exposure science, inhalation and cellular toxicology, life cycle implications

• f nano-enabled products and development of novel methods for the physico-

chemical and toxicological characterization of nanomaterials – Mission: Bring together ALL stakeholders: industry, academia, policy makers and the general public for sustainable development of NT industry – Industrial Partners: Over 20 partners ( BASF, Panasonic, Nanoterra, STERIS, AVECTAS , etc) – International in nature: Extensive network of collaborators including US Federal Agencies, and Universities around the world (ETH Zurich, NTU- Singapore, RIVM, MIT, SUNY, UMass, Northeastern Univ., NIOSH, CPSC, etc)

Funding Sources

Website: http://hsph.harvard.edu/nano

Harvard Center For Nanotechnology and Nanotoxicology (2015-2016)

Back Row (left to right): Ya Gao, Georgios Pyrgiotakis, Thomas Donaghey, Ramon Molina, Glen Deloid, Phil Demokritou, Dilpreet Singh, Joe Brain, Akira Tsuda, Edgar Diaz, Jin-Ah Park, Yanli wang and Xunzhi Zhu Sitting (from left to right): Caroline Cirenza, Sylvia Rodrigues, Archana Vasanthakumar, Sandra Pirela, Christa Watson, Jiayuan Zhao, Jenifer Mitchel, Guanghe Wang.

ENM Synthesis Core

Metals /Metal Oxides (FSP): P. Demokritou Metals/Metal Oxides (Wet synthesis): B. Moudgil Carbon based ENMs (Graphene, CNTs, etc): M. Strano Nanocellulose: D. Bousfield

ENM SYNTHESIS USING FLAME SPRAY PYROLYSIS (AEROSOL REACTORS)

Philip Demokritou, Harvard University

Flame Spray Pyrolysis Synthesis: Principle of operation

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 “Bottom up” approach for Me/MeO synthesis  Industry relevant method  A liquid precursor which contains the solution of an organo-metal is pumped though a nozzle.  Fine droplets are formed and dispersed using O2.  Droplets are ignited using a small CH4 flamelet  Primary Particles are formed by “homogenous nucleation”  Larger size aggregates and agglomerates are subsequently formed .  Particle formation and properties can easily be controlled by adjusting the flame conditions.

Versatile Engineered Nanomaterial Generation System (VENGES)

Features:  A Platform for pcm characterization & in-vitro , in-vivo tox studies  Based on industry relevant, flame spray pyrolysis (FSP) aerosol reactors  Versatile: All Me and MeO can be synthesized  P-c-m properties can be modified (primary particle and aggregate sizes, crystalinity, shape, etc).  ENMs are produced continuously in the gas phase allowing to transfer them with controlled agglomeration to inhalation chambers.

T1 QD

FMPS P-TRAK CO2, CO, RH, T2 NO2 BUFFER

QP QA QR

ENM sampling/ collection

QS 50 cm

HEPA HEPA HEPA

filter Animal exposure chamber

Flame Synthesis Animal Exposure System Exposure Monitoring Equipment

(Demokritou et al., Inh Tox. 2010)

Sampling Synthesis Exposure

(1) Demokritou et al. Inh. Toxicology, 2010 (2) Gass et al. Sus. Che. & Eng, 2012

Coating Reactor during Synthesis

Particle Collection Filter

In flight SiO2 coating of ENMs using the Harvard VENGES: Core-shell ENMs

(1) Sotiriou et al., Curr Opin Chem Eng 2011, 1, 3 – 10 (2) Xia et al., ACS Nano 2011, 5, 1223 – 1235 (3) Gass et al. Sus Chem and Eng, 2013, 7,39 (4) Teleki et al., Chem. Mater. 2009, 21, 2094–2100 (5) Sotiriou et al., Adv. Funct. Mater. 2010, 20, 4250–4257

• Tox. Pathways for Me and MeOx

Scalability?

• Reduce Toxicological footprint
• Maintain functional properties of ENMs

(optoelectronic, mechanical, etc)

• Scalability is the big challenge

Elements of a Safer by Design Approach

A Safer by Design Concept for flame-generated ENMs

ZnO Case Study: “Safer by design” cosmo-ceutical products

• The Yan: ZnO Nanorods

can block effectively UV while remain transparent to visible light1

• The Yin: ZnO release ions

and is photocatalytically active -> ROS generation- > Genotoxic2

1. Sotiriou et al. ES:Nano, 2014 2. Watson et al. ACS Nano, 2014

SYNTHESIS OF METAL AND METAL OXIDES USING HIGH PRECISION & THROUGHPUT HYDROTHERMAL REACTORS (WET CHEMISTRY)

Brij Moudgil, University of Florida

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• Most of the proposed particulate systems related research activities at the

University of Florida will be conducted at the Particle Engineering Research Center (PERC). PERC has a dedicated 25,000 ft2 facility (Particle Science & Technology Building) and 17,000 ft2 of laboratory space for the characterization and synthesis of particulate systems.

• Techniques are available for physical, mechanical and chemical analysis
• f particle systems including size, shape, surface area and porosity,

surface chemistry, rheology, tribology, interfacial phenomena, powder mechanics, powder flow and segregation.

• Processing facilities are provided in a 5000 ft2 high-bay pilot plant and

including crystallization, classification, size reduction, spray drying, coating, filtration and a wide variety of other techniques. Particle synthesis techniques include a 20 L stirred reactor, spray dryer, fluid bed dryer, wet and dry coating techniques, laser deposition and mechanofusion.

Facilities and Equipment at the University of Florida

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• The PERC works closely with the Major Analytical Instrumentation Center

(MAIC), the Interdisciplinary Center for Biotechnology Research (ICBR), and the Center for Environmental & Human Toxicology and has access to their facilities and equipment. MAIC specializes in materials characterization with a variety of state of the art methods such as high resolution scanning and transmission electron microscopy, x-ray photoelectron spectroscopy, and

• ther techniques. See http://www.maic.mse.ufl.edu for a full list of capabilities.
• The ICBR provides state-of-the-art facilities for biological sample analysis

ranging from transmission electron microscopy of biological samples to tandem mass spectrometry to gene chip analysis. See http://www.biotech.ufl.edu for a full list of capabilities.

• The Center for Environmental & Human Toxicology is working closely with the

PERC to resolve issues in nanoparticle toxicity (see http://www.nanotoxicology.ufl.edu) and has expertise in performing and interpreting in vitro and in vivo toxicity studies.

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• Image Pro v4.5 Optical Analysis Software, Paar Physica UDS 200

Rheometer, Optical Microscopes, Coulter LS 13320 Particle Size Analyzer, Colloidal Dynamics Acoustosizer, Brookhaven ZetaPlus, Microtrac Nanotrac. For a full listing of capabilities, see https://rsc.aux.eng.ufl.edu/resources/default.asp?s=PAIC.

• The center researchers also have access to facilities at Columbia

University (NSF I/UCRC Partner with UF) including atomic force microscope (AFM), quartz crystal microgravimatry (QCM), surface plasmon resonance spectroscope (SPR), Fourier Transform Infrared (FTIR) spectrophotometer, fluorescence spectrophotometer, microcalorimeter, surface area analyzer, scanning electron microscope - energy dispersive x-ray fluorescence (SEM-EDX), inductively coupled plasma (ICP) spectrophotometer, UV/visible spectrometer, particle size analyzer, High performance liquid chromatograph (HPLC/GPC), electron spin resonance spectrometer (ESR), Brookhaven photon correlation spectroscopy (PSC), analytical ultra-centrifuge, dynamic laser scattering equipment, zeta meters.

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Metal and Metal Oxide Materials

NPs Method Size Shape Au reduction of salts in aqueous conditions 1-100 nm spheres, rods,

• ther shapes

possible Ag polyol method < 50 nm spheres reduction of salts in aqueous conditions Co chemical reduction in flow reactor 10-100 nm spheres Fe thermal decom- position <100 nm spheres, rods Al sonochemical thermal decomposition 10-100 nm spheres Mn chemical reduction 10-100 nm spheres Zn vacuum evaporation & Condensation 10-160 nm hexagonal prisms SiO2 Stober synthesis 5 nm-1 μm spheres, rods, needles surfactant-templated synthesis

Capabilities/Expertise Relevant to HSPS-NIEHS Project

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Production of Core Materials

• Most inert metals (Au, Ag, etc.) and oxides (Silica, etc.)

produced in aqueous or water miscible media by chemical reduction.

• Reactive metals (Fe, Al, etc.) produced using organic or

vacuum synthesis methods.

• Flow reactor for high precision high throughput.

Silica Spheres

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Flow Reactor: Continuous Production of ENMs

• 1. Reagent supply pumps
• 2. Reactor
• 3. Heat exchanger
• 4. Backpressure regulator
• 5. Online characterization
• 6. Collection
• 7. Control hardware and software
• Continuous feedback control

and online characterization precisely control reaction conditions and product particle properties.

• Current system capacity is

30mL/min of product suspension.

• Work underway to increase

reactor throughput to 300mL/min within the next year.

• The scaled reactor system

will also have inline surface modification capabilities (initially gold and silver), permitting one step controlled production of surface modified/core-shell particles.

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Surface Chemistry

• Core inert metal particles electrostatically stabilized

(citrate frequently used).

• Reactive metals and some coinage metals have a

surface oxide layer.

• Anisotropic particles and certain spherical particles

use more strongly interacting compounds (ex. templating surfactants)

• Coinage metals easily modified using sulfur

compounds, metal oxides via carboxylates and silicon alkoxides

GRAPHENE, GRAPHENE OXIDE AND CARBON NANOTUBES

Michael Strano, Massachusetts Institute of Technology

Current Research Areas of Interest

• Energy Generation using Nanomaterials
• Exciton Engineering with Nanoconduits
• Molecular Transport through Nanopores
• Corona Phase Molecular Recognition (CoPhMoRe)
• Plant Nanobionics
• Synthesis and Fabrication of New Materials

Strano Research Group

New to the team (arriving January 2017)

Colloidal graphene and graphene oxide expert

Year 1 Focus: Graphene Production Methods

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NPs Method Size Shape Graphene oxide Hummer's method (1-4) 1-100 nm Sheet reduced graphene oxide Solvothermal reduction (3, 5) <100nm Sheet Mono-layer pristine graphene solutions colloidal production, dispersion and purification (2, 3, 5) 10 nm- 100 nm Sheet Bi-layer pristine graphene solutions colloidal production, dispersion and purification (2, 3, 5) 10 nm- 100 nm Sheet Tri-layer pristine graphene solutions colloidal production, dispersion and purification (2, 5) 10 nm- 100 nm Sheet

• 1. Hummers WS, Offeman RE. Journal of the American Chemical Society. 1958. 2. Jin Z et al. Nat Commun. 2013.
• 3. Shih C-J, Wang QH, Son Y, Jin Z, Blankschtein D, Strano MS. ACS Nano. 2014. 4. Sharma S, et al. The Journal of Physical Chemistry 2010.
• 5. Shih C-J, Vijayaraghavan A, Krishnan R, Sharma R, Strano, MS, et al. Nat Nano. 2011. 6. C. Bosch-Navarro et al. Nanoscale 2012.

Bilayer Graphene5

Oxidize and Exfoliate Reduce

Graphite GO rGO

COOH, OH, O-

Adapted from6

Unique to our MIT lab

Carbon Nanotube Production Methods

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NPs Method Size Shape Multi-wall Nanotube chemical vapor deposition (CVD) (1) 30 nm- 100 nm Rod Vendor bulk Preparation (Sigma 755117) Single-wall Nanotube chemical vapor deposition (CVD) (2) <100 nm Rod Vendor bulk Preparation: (Sigma 755710)

Hydrophilic Hydrophobic Corona Hetero- Polymer Or Surfactant Nanotube Sonication Suspended Nanotube Surface properties are critical to biodistribution and clearance.2,3

• 1. Kudo A et al. Journal of the American Chemical Society. 2014.
• 2. Iverson NM et al. Nature nanotechnology. 2013.
• 3. Singh R et al. Proc. Natl. Acad. Sci. 2006.

Scalable SWNT Separation – MIT Technology

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Tvrdy K et al. ACS Nano. 2013.

Scalable

How does the chirality influence nanotox?

Acknowledgements

NANOCELLULOSE SYNTHESIS

Douglas Bousfield, University of Maine

Cellulose Nanomaterials – Potential applications and characterization challenges.

Doug Bousfield, Calder Professor Department of Chemical and Biological Eng. University of Maine Orono, ME 04469

Cellulose nanomaterials

• Sustainable, renewable, recyclable, bio-compatable and

compostable.

Rheology Modifier

• Paints
• Cosmetics
• Food
• Adhesives

Specialty Packaging

Herrera et al. Vartiainen et al.

Tissue Engineering

• Scaffolds
• Bandages
• Ligament
• Blood Vessels
• Drug Delivery

Deng et al.

Fibers and Films

Dong et al., 2012

• Reinforcement
• Textiles
• Woven
• Films

Foams

Paakko et al., Soft Matter, 2008

• Acoustic
• Structural
• Thermal
• Absorption
• products

Moon, R. J., Martini, A., Nairn, J., Simonsen, J., & Youngblood, J. (2011). Cellulose nanomaterials review: structure, properties and nanocomposites. Chemical Society Reviews, 40(7), 3941-3994.

Example application

• Replace the aluminum coated polypropylene chip bag with

paper coated with cellulose nanofibers (CNF).

CNF provide the oxygen barrier that polymers are not able to obtain. Product here could be recycled in the paper stream and would decompose if littered on the land or ocean Potential contact with food. Large volumes.

Key forms of cellulose nanomaterials

• Mechanically produced. Cellulose

nanofibers (CNF), microfibrillated cellulose (MFC)

• Chemically produced. Cellulose
• nanocrystals. (CNC)
• Bacterial cellulose. (BC)

Development of a lab based “loop grinder system” for CNF synthesis

• Mechanical methods. Ultra-fine friction

grinder and pilot scale refiners.

Operate until “fines” content in fiber diameter sizer is over 90%

Challenges

• CNF is not easy to characterize. Fibers
• ften are connected and can have web
• r ribbon type structures.
• Length of fibers even more difficult.

Often the lengths are longer than the image.

• Chemical purity - cellulose is a natural

material that is separated from biomass through chemical processes. Other trace chemicals are likely present as well as micro-organisms.

• Cellulose may be hard to detect in a

biological system. There is no easy chemical signal compared to the background signals.

Initial steps-UPDATE

• A lab based reactor was developed which allows a systematic

synthesis of CNFs

• First CNF materials were synthesized and expected to be

shipped in December

• Working with Harvard to develop characterization methods

for CNFs which is not trivial.

• CNF samples have been tested with AFM, SEM and TEM.
• What properties of importance for nanotox studies ?Fiber

diameter? length? Node to node length?

Preliminary Characterization Data

• AFM images of tapping mode show that one

nanofiber has a width of 15-50 nm.

• The actual diameter is 52 nm
• Length several microns

Characterization Core

(David Bell, Georgios Pyrgiotakis)

Multi- Tier approach

Tier 1 characterization

• ENM core property characterization

– Size, shape, crystal structure/phase etc. – Concentration for suspension particles.

• QA/QC procedures in place: TIER 1 characterization performed at

the Synthesis site and repeated at Harvard for QA/QC purposes Tier 2 characterization

• ENM characterization expands to include

– Chemical composition, further surface functionalization, purity, etc – Colloidal characterization in biological media of interest – In-vitro dosimetric characterization

• Tier 2 may also include state of the art ENM specific characterization

– Chirality for CNTs, number of layers of Graphene/GO etc – Endotoxin and bacteria characterization

Tier 1 Characterization: State of the art Analytical Methods

Properties Methods Density Pycnometer Specific Surface area BET Porosity BET Crystal Structure XRD, TEM-SAD Primary Particle Size XRD-Rietveld analysis*, BET, TEM Shape, Aspect ratio TEM-Image analysis Size distribution TEM-Image analysis Properties Methods Hydrodynamic Diam. DLS Crystal Structure TEM-SAD Size TEM Shape, Aspect Ratio TEM-Image analysis Size distribution TEM-Image analysis, DLS Suspensions Dry Powder *Crystallite size

Tier 2: Chemical Characterization

Properties Methods Composition (Metal / Metal Oxide) ICP-MS, TEM-EDS, TGA, EC-OC, Raman spectroscopy, FTIR Composition (Carbon based materials) EC-OC, Raman spectroscopy FTIR Surface chemistry (for all ENMs) FTIR, XPS Stoichiometry (Metals/Metal Oxides) ICP-MS (metals and oxides), weight analysis (oxides) Sterility and Endotoxins Bacteria Culture, Colorimetric Assay

• Chemical composition, purity, endotoxin/bacteria
• levels. etc

* For selected ENMs

Tier 2: Colloidal Preparation and Characterization in Biological Media

• We are developing protocols for suspension preparation and

characterization

• ENMs will be dispersed in water and selected cell culture

media of interest.

• Colloidal Characterization will include:

Properties Methods Critical Sonication Energy DLS Size distribution DLS and TRPS, Polydispersity DLS, TRPS Zeta potential DLS, TRPS Specific conductance DLS pH pH meter Effective density VCM, AUC Dissolution* Dynamic Dialysis, ICP-MS Corona Characterization* LC-MS * For selected ENMs

Tier 2: Suspension prep, characterization in biological media

DeLoid et al., Nature Protocols , accepted , 2016

• We developed a detailed protocol that we plan to use for colloidal

preparation, characterization and dosimetric analysis for low aspect ratio ENMs (Paper just accepted for publication in Nature protocols) COMPLETED

• All developed tools/protocols will be made available upon request . Training

can also be provided if needed.

• We plan to start working developing will develop new methods for high aspect

ratio materials such as CNTs and 2D ENMs etc (Method development core)

Characterization Reports

Reference Material Repository Core

• Dr. Georgios Pyrgiotakis, Center Coordinator

Priorities for year 1:

1. Establish an ENM Centralized Repository (Harvard) (Completed)

– Develop storage guidelines Completed – Develop shipping guidelines Completed

2. Development of a web-based database to include all data for synthesis, characterization and nanotox studies (in progress, End of of 2016) 3. Development of web based portal for communication purposes with nanotox consortium (in progress, End of of 2016)

ENM and data flow diagram

• Development of the ENM repository lab

– Center Coordinator will be in charge on the day-to-day operations

• Electronic database

– Synthesis information (SOPs for each ENM, etc)

– Characterization data (Tier 1 and Tier 2) – NHIR labs will be able to request ENMs electronically – All related publications for reference ENMs will be archived and made available

• nline

Electronic Database Synthesis

ENMs

NHIR Nanotox Researchers ENM Central Repository at Harvard

Data ENMs Data

NIEHS Database

ENM Storage, handling and shipping: UPDATE

– ENMs after synthesis to be stored in controlled environmental conditions (Ar atmosphere, UV protection, low RH/O2 levels, etc) – Develop guidelines for containers to be used to store ENMs inclusive of cleaning procedures, type of containers etc) (COMPLETED) – Develop shipping guidelines (COMPLETED)

Central ENM Repository Lab (Harvard)

• MBRAUN glovebox

– Maintains <0.1ppm H2O, <0.1ppm O2 levels at all times. – Argon atmosphere, UV shield, RH, T logging Working area

• ENM

packaging

• ENM sample

preparation etc. Storage area Airlocks

Container prep area

Particle free hood for container preparation ENMs packing and preparation area

Methods Development Core

Philip Demokritou

Development of methods to concentrate ENM suspension for nanotoxicology research

Challenge

• All ENMs in suspensions were stored at 50ug/mL to ensure size stability
• ver time
• Higher concentrations of ENMs in suspension might be needed for

nanotox research.

• Challenge: How to concentrate the ENM suspension without altering

important colloidal characteristics such as Hydrodynamic Radius.

• Currently we are exploring two methods:

– Centrifugation (not recomended):

• Spin the suspension at high RPMs (5000 and above) and remove

supernatant.

• Pros: This method concentrates the ENMs but does not alter the ionic

strength of the solution.

• Cons: 1) The ENMs can aggregate 2) It varies with particle size and

material 3) Limited quantity (300 ml)

– Vacuum Evaporation/Rotary Evaporator:

• Evaporate the water under vacuum at 30 C.
• Pros: 1) Very precise control of the evaporation and minimum chance
• f forming aggregates 2) Can concentrate up to 1 l at a time.
• Cons: Concentrates salts and ions that can complicate interactions in

biological media.

Vacuum Evaporation/Rotary Evaporator

• The rotary evaporator

can effectively concentrate the suspension by a factor

• f 10 without

significantly impacting the particle size distribution (diameter and PDI).

• WE are working on:

– Evaluating long term stability of the suspension – Develop a method for estimating the concentration beyond the concentration factor. 10 x

Assesing food-iENM and GIT-iENM interactions: iENM transformations and effects on bio-kinetics and toxicity

Project: Ingested ENMs (iENMs)

Food and GIT ENM Transformations: Development of a lab based GIT simulator for assessment of iENM transformations

Stomach

• pH 1-3
• Enzymes
• Salts
• Biopolymers
• Agitation
• 30 min – 4

hours

Foodborne Inorganic Nanoparticles (NPs)

Small Intestine

• pH 6-7.5
• Enzymes
• Salts, Bile
• Biopolymers
• Agitation
• 1 – 2 hours

Mouth

• pH 5-7
• Enzymes
• Salts
• Biopolymers
• 5 – 60 s
• Challenges: Characterization of

iENM transformations in complex media – New ENM characterization methods need to be developed

Development of Standardized methodologies across the suspension preparation- characterization- dosimetry continuum for 2D and high aspect ratio ENMs

In Collaboration with Prof. Strano at MIT

Development of Methods for in-vitro dosimetry for high aspect ratio and 2D materials for in-vitro studies

DeLoid et al., Nature Protocols , accepted, 2016

• We have developed standardized methodologies for low aspect ratio

ENMs across the suspension preparation-characterization-dosimetry.

• Expand to include 2D and high aspect ratio ENMs

Advanced Characterization Algorithms for Polydispersity Characterization

High-Throughput Single Particle Tracking (movie)

Single Particles Bundles Temporal Comparisons Aggregation Surface Binding Degradation Shifts in Size Distribution Properly handling polydispersity and complexity in nanoparticle dispersions remains a challenge We are developing a next generation of characterization tools to address this.

Corona Characterization on Carbon Nanotubes

In Collaboration with Prof. Strano at MIT

New Methods to Understand the Soft Corona

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Wrapping molecule

Plate Reader nIR

q/Kd [M-1]

q Kd [uM] Kd [uM] (GTTT)

7 319.8 [231 408.6] 9.24*10-3 [-41.3 59.8] *10-3 28.9 10.55 [5.22 15.89]

SC

335.7 [268 403.5] ∙ ∙ ∙

SDS

391.7 [273.1 510.4] ∙ ∙ 0.85 [0.60 1.10]

(GT)15

444.2 [359.5 528.9] 9.36*10-3 [-18.5 37.17] *10-3 20.81 5.83 [4.30 7.37]

(AT)15

488.9 [201.1 776.7] 3.76*10-3 [-8.78, 16.3] *10-3 7.52 7.34 [5.92 8.76]

SDBS

498.4 [381.9 614.8] ∙ ∙ ∙

SDS+SC

770.2 [665.7 874.8] ∙ ∙ 1.07 [0.77 1.36]

Dextran

1174 [1105 1244] ∙ ∙ 1.067 [0.89 1.24]

PS

(MW 200k) 1182.9 [936.5 1429] 3.73 [-2.81, 2.82] 339.06 3.15 [2.66 3.63]

Chitosa n

2097 [1633 2562] 5.88*10-3 [1.06 10.71] *10-3 2.81 12.17 [9.39 14.95]

PS

(MW 70k) 2439.5 [1801 3078] 1.37*10-2 [-2.01 4.76] *10-2 5.60 ∙

Inverse riboflavin (probe) adsorption (1/mM) Inverse riboflavin (probe) concentration (1/uM)

Using a method under development, we use standardized probe molecules such as riboflavin to probe the soft corona phase around suspended nanoparticles. The method can quantify the number of binding sites (q) within and on the soft corona as well as the dissociation constant (Kd)

Kd can then be compared to other methods

Trend yields q and Kd for each probe and each corona phase

Assessment of ENM stability over time under environmental conditions: Effects on biological activity

Investigating and Documenting ENM Stability

MAIN CONCERN – PCM changes due to storage/handling conditions lead to measurable biological outcomes

• Surface OXIDATION (aging, passivation)
• DISSOLUTION & subsequent chemical

transformations

• SURFACE exchange phenomena (adsorption of
• rganics, exchange of cations & anions)
• ?
• THESE ARE LARGELY SURFACE - DRIVEN PHENOMENA !!!

and SURFACE CHEMISTRY RULES!

Methods – Stability

• Representatives of ENM classes

– Metals – Metal Oxides – 2-D materials - Graphenes – Nano cellulose – ?

• Identify and monitor signature properties over time under

relevant storing and handling/processing condition

– Define relevant scenarios – dry vs. wet – Develop initial SOP based on existing best practices – Investigate stability for each scenario – Incorporate findings into revised SOPs

Signature Markers

• Surface oxide thickness

– XPS, High Res TEM

• ROS generation, Surface activity index

– FRAS & direct oxidation of other probes (Trolox)

• Organics on the surface

– TGA, TGA/GC-MS, …

• Other properties - material specific

– Can we take advantage of new sensor technologies ?

Administration and Research Coordination Core

Philip Demokritou

Administration and Research Coordination Core (ARCC)

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A hierarchical organizational structure inclusive of an External Science Advisory Committee Center Director- PI

• P. Demokritou

Center Coordinator

• G. Pyrgiotakis

ESAC (5 people,) Steering Committee

(D. Bell, D. Bousfield, B. Moudgil, M. Strano)

External Scientific Advisory Committee( ESAC)

• Dr Vince Castranova (Former NIOSH- HELD Nano-program

Director, currently at UWV)

• Professor Sotiris Pratsinis ( ETH, Zurich, ENM synthesis)
• Professor Ahmed Bushnaina (NEU, Director, NSF Nano-

manufacturing Center)

• Professor Robert Hurt ( Brown U., ENM synthesis and Nanotox)
• Dr Treye Thomas ( US CPSC, Nano-program Director )

Research Integration Activities for Year 1

Research Integration:

• Discussion/visits with NHIR investigators and NIEHS program officer to

identify areas for collaborative research on method development and support on current research activities ( fall 2016)

• Annual meeting and symposium for Harvard-NIEHS Center to present
• ur work and promote integration/collaboration among its members.

NHIR investigators are welcome to attend!

• NIEHS annual meeting (December 2016 @ NIEHS, Harvard for 2017?? )

Communications./Outreach:

• Develop a Center Website to outline core activities of the Center (in

progress, to be completed in December ).

• Nanolecture series: (webcast) to start in January 2017. Seminars from

leaders in application/material. NHIR members are welcome to present their research

• Publications, conference presentations ( 2 papers are in submission)

Reference ENMs: Timeline Year 1

Timeline for year 1

2016

October 15, 2016

• Al2O3 (~20 nm) (FSP)
• SiO2 (~15 nm) (FSP)
• Au* (15 nm) (WS)

December 31, 2016

• SiO2/Ag 5% w/w Ag (FSP)
• SiO2/Ag 20% w/w Ag (FSP)
• Cellulose Nanofibrils (CNFs)
• CeO2 (two sizes)(FSP)
• Fe2O3 (two sizes) (FSP)

March 31, 2017

• Graphene
• Graphene Oxide
• Cellulose Nanocrystals

2017

Other ENMs that can be made available in year 1, if needed:

• Comparative Materials: Welding fumes? GRAS materials for iENM studies

(TiO2, SiO2)

• Other Me/MeO: MnS, ZnS ?

FSP: Flame Spray Pyrolisis (Powder form). WS: Wet synthesis (suspension). ENMs will be citrate capped. Other capping agents can be made available

Thank You!