Lecture 8 Nanotechnology: Solutions to environmental problems?

1. Lecture 8Nanotechnology: Solutions to environmental problems?

2. Definition • Nanomaterials is a field that studies materials with morphological features in the nano-scale, and especially those that have special properties stemming from their nano-scale dimensions. Nano-scale is usually defined as smaller than a one tenth of a micro-meter in at least one dimension (100nm), though this term is sometimes also used for materials smaller than one micro-meter.

3. Nanomaterial properties • An important aspect of nanotechnology is the vastly increased ratio of surface area to volume present in many nano-scale materials (e.g., upwards of 100 m2 per gram), which makes possible new quantum mechanical effects. One example is the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. The effect becomes pronounced when the nanometer size range is reached. This also includes changes in physical property. • Such striking features such as nano-scale gold which is normally inert becomes very active/catalyst. Nanoscale gold

4. Nanoscale Size Effect • Realization of miniaturized devices and systems while providing more functionality • Attainment of high surface area to volume ratio • Manifestation of novel phenomena and properties, including changes in: • - Physical Properties (e.g. melting point) • - Chemical Properties (e.g. reactivity) • - Electrical Properties (e.g. conductivity) • - Mechanical Properties (e.g. strength) • - Optical Properties (e.g. light emission)

5. History of Nanotechnology • ~ 2000 Years Ago – Sulfide nanocrystals used by Greeks and Romans to dye hair • ~ 1000 Years Ago (Middle Ages) – Gold nanoparticles of different sizes used to produce different colors in stained glass windows • 1959 – “There is plenty of room at the bottom” by R. Feynman • 1974 – “Nanotechnology” - Taniguchi uses the term nanotechnology for the first time • 1981 – IBM develops Scanning Tunneling Microscope • 1985 – “Buckyball” - Scientists at Rice University and University of Sussex discover C60 • 1986 – “Engines of Creation” - First book on nanotechnology by K. Eric Drexler. Atomic Force Microscope invented by Binnig, Quate and Gerbe • 1989 – IBM logo made with individual atoms • 1991 – Carbon nanotube discovered by S. Iijima • 1999 – “Nanomedicine” – 1st nanomedicine book by R. Freitas • 2000 – “National Nanotechnology Initiative” launched

6. Graphene Graphene is made of pure carbon, with atoms arranged in a regular hexagonal pattern similar to graphite, but in a one-atom thick sheet. It is very light, with a 1 square meter sheet weighing only .77 milligrams The Nobel Prize in Physics for 2010 was awarded to Andre Geim and Konstantin Novoselov at the University of Manchester "for groundbreaking experiments regarding the two-dimensional material graphene".[5]

7. Nanomaterial origins

8. Nanotechnology Applications Information Technology Energy • More efficient and cost effective technologies for energy production • Solar cells • Fuel cells • Batteries • Bio fuels • Smaller, faster, more energy efficient and powerful computing and other IT-based systems Consumer Goods Medicine • Foods and beverages • Advanced packaging materials, sensors, and lab-on-chips for food quality testing • Appliances and textiles • Stain proof, water proof and wrinkle free textiles • Household and cosmetics • Self-cleaning and scratch free products, paints, and better cosmetics • Cancer treatment • Bone treatment • Drug delivery • Appetite control • Drug development • Medical tools • Diagnostic tests • Imaging

9. Environmental Applications for Remediation. Zero valent nanoscale iron. (Tetrachloroethane to ethene C2Cl4 + 4Fe0 + 4H+ → C2H4 + 4Fe2+ + 4Cl−

10. Risks associated with environmental clean-up

11. Addition of different forms of nano-scale iron (20-80nm dia.) to remediate Trichloroethene (TCE) in ground water Dehalogenation of 350 mg/L TCE by ( ) micro-scale Fe particles, ( ) nano-scale Fe particles, ( ) annealed nano-scale Fe particles, and ( ) Ni/Fe bimetallic nano-scale particles. ( ) Control (no Fe particles). Data are concentration TCE (mg/L) remaining in water over a time of 2928 hours. Error bars are 1 x SE (3 replicates).

12. Membrane Filter Technology III Source: http://web.evs.anl.gov/pwmis/techdesc/membrane/index.cfm

13. Water Filtration Chart Source: Adapted from http://http://www.sasconsulting.ca/Files/Spectrum.jpg

14. Nanomaterials for the intentional killing of pathogenic bacteria

15. MRSA or Methicillin-Resistant Staphylococcus aureus VRE or Vancomycin-Resistant Enterococci FQRP or Fluoroquinolone Resistant Pseudomonas aeruginos. Source: CDC data from intensive care units of hospitals participating in a CDC surveillance program, USA Antibiotic Resistance, a Global problem Macrolide and Penicillin resistance in S. pneumoniae in the year 2000 The numbers represent the percentage of resistance to Macrolide and penicillin respectively in 2002 Source: GlaxoSmithKline

16. Nanomaterial for killing cells Smelly socks- isovaleric acid, which is produced when Staphylococcus epidermidis are activated by skin contact. Silver nanoparticles act primarily in three ways against: • nanoparticles attach to the surface of the cell membrane and drastically disturb its permeability and respiration activity; • they are able to penetrate inside the bacteria and cause further damage by possibly interacting with sulphur- and phosphorus-containing compounds such as DNA; • nanoparticles release silver ions, which have an additional contribution to the bactericidal effect of the silver nanoparticles.

17. Toxic effect of different shaped nano-silver Sharp end particles are more toxic than spherical forms.

18. Killing water borne bacteria using nano-scale titania No bacterial kill with UV alone or with TiO2 without UV activation • 1 g/L = 94% kill • 0.1 g/L = 87% kill 1 g/L TiO2 + UV 0 minutes 10 minutes 20 minutes 30 minutes 40 minutes 50 minutes 60 minutes

19. Control Smart nanomaterials for killing microbial cells Killed E. coli

20. Nanomaterial manipulation of cells Bacteria coated in nano-gold

21. Combined method of killing cells with nanomaterials Attachment of cells with nanomaterial-antibodies. An antibody, is a large Y-shaped protein used by the immune system to identify and neutralise foreign objects such as bacteria and virus.

22. Nanomaterials for gene transfer and drug delivery Cell recognition, magic bullet. Lower dose required to cure cancer patients. Results in particles being released into the urine/environment.

23. Detection of cells and chemicals in the environment.

24. Sensors for specific bacteria- or indeed ions that may inhibit cells

25. Nanomaterial manipulation of cells Bacteria coated in magnetite

26. Tagging and manipulation of cells

27. Manipulation of bacterial cells (and biocides) with magnetic nanomaterials

28. Mechanism of toxic response to nanomaterial exposure • Key parameters such as particle size and shape have a great influence on cell interactions. • Also surface chemistry such as hydrophilic characteristics and functional groups. • Release of free oxygen radicals

29. Fate of nanomaterials in the environment and their Bio-accumulation in the food chain.

30. Uptake by plants Arabidopsis thaliana 1 mg l-1 Zn2+ 10 mg l-1 Zn2+ Control 1 mg l-1 Zn NP 10 mg l-1 Zn NP Zn2+ = zinc solution, Zn= nano-scale Zn 50 nm

31. Impact of nanoscale-Fe on river microbial communities

32. Results – Oxidation-Reduction Potential (ORP)

33. Impact of nano-iron on cultural river water bacterial counts A significant increase also seen in total cell counts (DAPI staining)

34. L 0 1 3 6 11 21 36 0 1 3 6 11 21 36 0 1 3 6 11 21 36 L Impact of nanoscale-Fe on river bacterial communities (genetic finger print by DGGE) Riverwater (RW) RW + Nano-Fe RW + Micro-Fe

35. Clean synthesis of nanomaterials

36. Microbial synthesis of nanomaterials by plant and microbial cells. Microbial synthesis of nanomaterials can be much cheaper, cleaner and more uniform.

37. Nanomaterials and environmental • Remediation recalcitrant contaminants. • Nano-filtration of contaminants. • Killing pathogens. • Sensors of pathogens and contaminants.