Opportunities and Implications for Green Nanotechnology in Industry for the 21st Century Reducing Principles to Practice June 16, 2010 John M. Miller, Ph.D. Dune Sciences, Inc.
Nanotechnology CLEAN WATER ENERGY MEDICINE ELECTRONICS
Green Nanotechnology? Toxic components Poor material utilization High waste/product ratio (E ratio) Unknown/unmonitored /uncontrolled exposure pathways End of life not considered
Product Stewardship by Design What happens at end of product life Recycling/ Repurposing Waste disposal Manufacturing Materials sourcing Alternate chemicals Process efficiency Workplace safety Waste management End of Life Product/ Application Usage scenarios Exposure pathways Product Labeling Product Registration
SOCKS*: A case study for Greener Nano * And other garments/apparel.
NanoSilver BENEFITS CONCERNS Silver ions kill bacteria, viruses, and fungi Reduces spread of infection/ harmful effects of microbes Silver NPs provide delivery vehicle for controlled release of silver ions Release and related toxicity of nanosilver and silver ions Occupational and consumer exposure to silver Production and waste treatment of Silver Prolonged product life (Reduces waste) Ttl Total silver entering environment Reduced use of other chemicals(detergents, bleach)
A Safer Solution Specific Objectives Demonstrate high antimicrobialefficacy against a wide range of pathogens for treated products. Permanent bonding of nanoparticles to substrate surfaces to eliminate risk of nanoparticle release and increase product lifetime. Increase utilization of nanoparticles in surface coatings. Low cost, scalable process. Implement appropriate control measures to prevent exposure to and release of nanoparticles.
LinkedON Technology Permanent bonding of silver prevents release of free particles. Reduces total amount of silver required. Scalable manufacturing process. LinkedON can be applied to a broad range of nanomaterials with different compositions, shapes and sizes.
LinkedON Silver Active Materials Stabilizing shell hll Starting material is a byproduct of a treatment for FDA approved implantable medical devices. Silver metal nanoparticle reservoirs stabilized in water Core: Silver metal D core = 11 ±6 nm Core Shell: Polysorbate 20 Biocompatible low molecular weight polymer TransmissionElectron Microscopy 11 +/ 6 nm 25 nm 250 nm
Antimicrobial Activity Sample Type Zone of Inhibition Organism LinkedON Silver particles Silver particles Methicillin resistant S. 3.5 2.5 aureus Vancomycin resistant 2 2 Enterococcus P. aeruginosa 3.5 5 E. coli 4 3.5 C. Albicans 7.5 7.5 S. Aureus STCN 7.5 8 Antimicrobial activity is not affected by the LinkedON processing of the silver particles. Antimicrobial activity is proportional to size of margin around treated cellulose.
Processing and Treatment Textile Treatment Process Ag Fabric Δ Ag Ag Ag Textile Fiber Ag Ag LinkedON Coatings LinkedON Linker Solution LinkedON Silver Antimicrobial Solution (10 15 15 ppm silver) Binding to Fabric Exhausts Silver Linker solution ingredients are all non-toxic. Utilization of >90% of active ingredient. Spent solutions: Silver concentration below 5 ppm. LinkedON coatings are durable for more than 50 launderings.
Process Control Can tune loading of silver NPs onto fabrics with repeatability/ reproducibility to reduce total amount of silver. Can bind particles to a variety of textiles including: cotton, rayon, nylon, polyester, and others. Opt tical density solution concentration
Antimicrobial Performance Demonstrated >85% improvement in product lifetime. Treated fabrics kill more than 99% of bacteria after 30 launderings. 1 Environ. Sci. Technol., 2008, 42 (11), 4133 4139
Process Scale up Manual Treatment 1 L capacity 2 socks / hr Mathis JFO Pilot Scale 20 L capacity 80 pairs of socks / hr Thread Jet Treatment Greater control over critical process parameters results in more uniform coatings compared to manual treatments. Burlington Tex O Mat Dye Machine Industrial Scale 50 L capacity 200 pairs of socks / hr Increasing Scale
Waste Management Exhausted LinkedON solution < 5 ppm Ag Precipitation of Ag NPs in holding tank with NaCl. Water filtration and reclamation. Reclaimed water (<1 ppm Ag) can be reused din LinkedON process Recovered Ag ppt can be recovered and recycled Validated waste management approach to minimize risk of unwanted release or exposure to silver nanoparticles
Greener Nano ScoreCard Goals: Demonstrate high antimicrobial efficacy Permanent bonding of nanoparticles to surfaces Increase utilization i of nanoparticles il Low cost, scalable process Implementing appropriate control measures to prevent exposure to and release of nanoparticles. It is possible to develop nanomaterials and nanomanufacturing approaches that can profoundly impact our society and minimize the risk of harm to human health or the environment while still being profitable.
Commercialization Challenges Mounting concern about toxicity and release of nanomaterial products creates unique challenges for commercialization Regulatory requirements not defined Limited data on toxicity under relevant exposure conditions. Poor understanding of fate and transport of nanomaterials Standardized testing/characterization methods not adopted New reality that manufacturers New reality that manufacturers must prove safety!?
SMART GRIDS TM SMART GRIDS With functionalized surfaces SAMPLE Preparation Nanoparticle Capture Microscopy and image analysis Simplified protocols, accurate characterization, reproducible data.
Improved Metrology for Nanoparticles Functionalized Smart Grids Smart Grids currently used by: Other grids NIST NCI NIOSH CDC DHS EPA SMART Grids eliminate drying effects.
Standards Correlative Microscopy 60 nm NIST standard Gold nanoparticles. Complementary surface analysis: XPS, Auger, SIMS, AFM, STM, SEM, EELS, and others.
Controlled Release of Silver Ions from Particles LinkedON Silver on TEM Grid As LinkedON After 1 Week in H 2 O After 3 Weeks in H 2 O 10 15 20 25 30 35 40 More 5 10 15 20 25 30 35 40 Diameter (nm) 2 3 4 5 6 More diameter (nm) Diameter (nm) Ave. diameter: 18 ±6 nm Ave. diameter: 11 ±6 nm Ave. diameter: 3 ±1.5 nm Silver ions slowly elute in presence of water over time. Areal density of particles remains unchanged.
Conclusions Nanotechnology offers the opportunity to fundamentally improve the quality of life and help to ensure a sustainable future. Demonstrated it is possible to realize both the advantages of nanoenabled products and to do so in a responsible fashion. The new reality is that policy will play an important role in The new reality is that policy will play an important role in commercializing new nano enabled technologies.
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