Nanotechnology: Environmental Impact

1. Nanotechnology: Environmental Impact • Dr. Vicki Colvin • Associate Professor, Chemistry Department • Rice University • Houston TX 77025

2. NanoBioEnvi WET DRY Center for Biological and Environmental Nanotechnology Science and Engineering at the WET / DRY interface of Nanotechnology

3. What – Me Worry ? MOTIVATION • Nano in Bio  Medicine • The unique optical, electronic, structural properties of the dry side when added to biomolecules will result in powerful new medical treatments and diagnoses. • Bio in Nano  Materials/Devices • Manipulation and assembly of nanostructures from the dry side into materials and functional devices using machinery from the wet side will enable new technologies. • Nano-Bio in our Environment  Responsibility • Risk Assessment / Risk Reduction

4. 1) Adsorption + Natural Nanoconjugates (3A/1A) 2) Aggregation (ppt) 3) Biotic Uptake

5. “A tool for sustainable development rather than an environmental liability” Nanotechnology and the Environment • Enabling technologies to meet many needs • water, wastewater • hazardous waste • resource recovery • pollution prevention • Environmental consequences of new technologies • focus on transport, transformation, and fate of nanostructures • proactive approach early in the process Water treatment plant

6. Past failures to consider environmental consequences early have been costly: semiconductor industry (metals, solvents) synthetic chemicals (PCB, DDT, Freon) applications of natural compounds (chlorine, asbestos) transportation, energy (air pollution, global warming, nuclear wastes) Small adjustments early in the trajectory of a technology have large consequences. Must introduce the environmental perspective early into the culture of emerging technologies (research and educational missions). What – Me Worry ? Lessons from Earlier Technologies Ozone hole

7. Particle-mediated transport size surface chemistry (hydrophobic) Potential for bio-assimilation direct consequences associated contaminants Nanostructures: Environmental Impact?

8. sorption/ desorption Nanoparticles in Aqueous Environments organic compounds/ macromolecules/ contaminants naturally occurring particles nanoparticles Bio-uptake 3A1 transport aggregation 3A2 deposition 3A3

9. Separation Technologies Need knowledge of fundamentals of transport and chemistry at the nanoscale. Water treatment facility • Assess capabilities of existing separation technologies • Environmental quality control • Nanomaterial production • Conceive new separations processes Computational fluid dynamics simulation (Wiesner)

10. Nanostructured Membranes for Separations • Tailor membranes for permeability, selectivity, reactivity, low fouling • narrow pore size distribution • high porosity • high specific surface area • nanostructured asymmetry Pore size distribution of alumoxane membrane (Barron, Wiesner) • Two initial strategies • metal-oxane derived membranes • deposition-controlled template design Asymmetric membrane (Barron, Wiesner)

11. Nanostructures Biological Engineering Environmental Engineering Value Added by Center • Environmental risk assessment • Nanomanufacturing facility • Integrated research program and expertise • Computation (transport/removal of nanostructures) • Materials chemistry (membrane design) • Nano surface chemistry (adsorption/desorption) • Biology (bio-uptake into cells)

12. Why should we be concerned now? • Nanotechnology is a rapidly growing field of industry • Predicted to be $700 billion market by 2008, Nanobusiness Alliance, November 2001 • Preventative measures preferable • Past industrial failures associated with biouptake.accumulation have had grave environmental consequences (i.e., DDT) • More economical

13. Biouptake of Nanoparticles • Nanoparticles may enter cells via: • Endocytosis • Receptor activation for initiation • Membrane penetration • Generally occurs with very hydrophobic particles • Transmembrane channels • May be seen only with very small nanoparticles (< 5 nm)

14. Biouptake and Adsorption • Many types of molecules will adsorb to nanoparticles in complex aqueous environments • Adsorbed molecules may dictate biological interactions, especially biouptake Biomolecules (i.e. proteins) Synthetic chemicals (i.e. pesticides)

15. Factors Influencing Adsorption • Occurs to a greater degree on: • Hydrophobic particles • Charged Particles • Amphiphilic or charged molecules most likely to adsorb • Macromolecules generally adsorb most strongly

16. Specific Protein Interactions with Nanoparticles Can Occur Example: Antibody interacting with C60 Provided by Jianpeng Ma Other examples:Semi- conductor binding peptides Metal-binding peptides

17. Cellular Uptake of Nanoparticles • So far, most nanoparticles do not interact with cells unless their surface is bound to cell-interacting molecules Receptor-targeted Nanoparticles Non-targeted Nanoparticles

18. More Studies are Needed to Understand Biouptake! • Systematic studies over a range of nanoparticles sizes and surface chemistries • Evaluation of specific Nanoconjugates • Nanoparticles bound to particular molecules that may play a role in biouptake

19. Bioaccumulation? • Accumulation of a substance within a species due to lack of degradation or excretion • Most nanoparticles are not biodegradable • If nanoparticles enter organisms low in the food web, they may be expected to accumulate in organisms higher in the food web Need to understand possible health effects of nanoparticle exposure!

20. Nanoparticle Aggregation • In complex aqueous environments, many types of nanoparticles undergo aggregation • Biological interactions with aggregated nanoparticles similar to bulk materials • Intracellular aggregation may cause extensive damage and induce cell death • May expect similar results to diseases caused by protein aggregation (i.e., sickle cell disease)

21. Facilitated Transport of Toxins • Adsorbed molecules will enter cells if nanoparticles do • Substances normally excluded from cells may then enter • Substance may be toxic to • that organism or ones • further up the food web Toxin

22. Any evidence for this? • Many studies show facilitated transport of heavy metals, fertilizers, and pesticides into fish • Chemicals adsorb to naturally occurring colloidal particles, resulting in tremendous increases in biouptake

23. Complement Proteins Antibodies (IgG, IgM) Nanoparticle-Induced Activation of the Immune System • In an organism, proteins will be the dominant adsorbate. All extracellular proteins involved. • Proteins change their conformation during adsorption, and thus may change function.

24. Complement Activation Clustered IgGs or 1 IgM Nucleophilic groups on surface Complement protein reactions via Alternative Pathway Complement protein reactions via Classical Pathway •Generation of Anaphylactic Agents C3A & C5A •Generation of Leukocyte Receptor C3BC5B Tissue Damage Formation of Membrane Attack Complex (MAC)

25. Potential Effects? Inhaled particles induce inflammation in respiratory tract, causing tissue damage. Example: Inhalation of silica particles in industrial workers causes “silicosis”. Ingested nanoparticles may cause liver damage. Ingested nanoparticles (i.e. for oral drug delivery) have been found to accumulate in the liver. Excessive immune/ inflammatory responses cause permanent liver damage.

26. Possible Induction of Auto-Immune Disorders Phagocytosis Macrophage “Instructs” lymphocytes to generate antibodies against phagocytosed material Lymphocyte Produces Antibodies Macrophage Phagocytoses Foreign Material, Binds C3BC5B These antibodies may recognize proteins that were adsorbed to the nanoparticles. These were denatured proteins from the same animal. Antibodies may cross-react with “native” proteins, inducing Auto-Immunity. Y Y Y Y Y Y Y Y Y Antibodies

27. Auto-Immune Disorders are Linked to Small Particulates Example: Wear debris is generated by orthopedic implants. Patients with such implants have a statistically significant rise in the incidence of auto-immune diseases. Example: Industrial workers who breathe particulate matter (i.e. silica dust) have a significantly higher risk of auto-immune disorders.

28. The “Dark Side” of Nanotechnology? • There has not been enough research done to know what the biological implications of NanoIndustry will be. • There is evidence to suggest possible problems. • As a scientific community, we should be pro-active in addressing the possible risks.