CHE5480 Summer 2005

1. CHE5480 Summer 2005 Nanostructures: Introduction

2. TOPICS: • Theory: (Dr. Lee) • Experiments (Dr. Newman) • Computer: (Dr. Neeman) • Attending Nanotechnology Meeting

3. What size is a nanometer? • A nanometer (nm) is 10-10 meter (1 m = 3.28 ft). Nanotech: from1 nm to ~100 nm Albumin 6.5 nm Ribosome 25 nm Argon 0.3 nm CH4 0.4 nm H2O 0.3 nm Red Blood Cell 2000x7000 nm

4. What size is a nanometer? (2) HIV virus 125 nm Red Blood Cell 2000x7000 nm Argon 0.3 nm CH4 0.4 nm H2O 0.3 nm ~1 nm ~100 nm Albumin 6.5 nm Ribosome 25 nm

5. From NNI (National Nanotechnology Initiative) The Initiative and its Implementation Plan : The essence of nanotechnology is the ability to work at the molecular level, atom by atom, to create large structures with fundamentally new molecular organization. Compared to the behavior of isolated molecules of about 1 nm (10 -9 m) or of bulk materials, behavior of structural features in the range of about 10 -9 to 10 -7 m (1 to 100 nm - a typical dimension of 10 nm is 1,000 times smaller than the diameter of a human hair) exhibit important changes. Nanotechnology is concerned with materials and systems whose structures and components exhibit novel and significantly improved physical, chemical, and biological properties, phenomena, and processes due to their nanoscale size. Definition of Nanotechnology:

6. 22 National Agencies in NNI:(11 of which have R&D budgets.)

7. National technology for the 21st century: Leading to a new industrial revolution • Initiatives (NTR): • Research on fundamental understanding and discoveries. • Design of nanostructured materials. • Nanodevices: information, bio, medical. • Applications of nanomaterials and devices to energy, health, evironment, and security. • Education of a new generation of skilled workers.

8. History of NNI: (National Nanotechnology Initiative) • 1998: IWGN (Interagency Working Group on Nanotechnology)—National technology for the 21st century: Leading to a new industrial revolution. • 2001: NNI (Nantional Nanotechnology Initiative)—Funding at ~500 million. • 2001 NSET (National Science, Engineering, and Technology)

11. Nanostructures: Old and New

12. Nanostructured Materials: • Carbon nanotubes • Aerogels • Zeolites • Dendrimers • Self-assembled monolayers • Nanoparticles • Nanowires • NEMS, etc.

13. NSF Web

14. Applications of nanotechnology: • A new industrial revolution (on the scale of the transistors in 1950s). • Potentially it will pervade all sectors of industry and technology. • Essentially in the following areas: Information, health, space, environment, defense, etc.

15. Nature’s Nanodesigns

16. Mimicry of Nature—1 The Lotus Effect Water runs off. • Both surface chemistry and surface topology influence the hydrophobicity -slip. The surface contains “waxy bumps”. • Using the “Lotus effect” (that lotus leaves are highly hydrophobic), one can achieve slip flow (Tretheway & Meinhart –UCSB, Silane. Phys. Fluids 2002). Water beads up on papillae. Papillae on leaves.

17. Mimicry of Nature—2(The lotus leaf surface)(Feng 2002) Papilla μ

18. Mimicry of Nature—3Water Strider Gao, X. F. & Jiang, L. Water-repellent legs of water striders. Nature432, 36 (2004). μ

19. Nanosensors:

20. Nanosensors: • Using nanostructued materials for detection of trace amounts of chemical and biological agents. (Medical, space, environmental, homeland security).

21. Detection of Pathogens—(Homeland Security):

22. Anthrax: (Woolverton, Kent State U.)

23. Detect Viruses(Lieber, Harvard)

24. ...and find a Cure!!!

25. Antimicrobial Nanoemulsion(James Baker, U. Michigan) • Use of soybean oil emulsified with surfactants. Drops ~400 – 600 nm. • The droplet do not coalesce with themselves . High surface tension make them coalesce with other lipid droplets, killing bacteria. • Safe for external use. Not safe for red cells, or sperm.

26. The droplets fuse with cell membrane of microorganisms resulting in cell lysis. • Very effective in killing: – Bacteria,  – Bacterial spores,  – Enveloped viruses, and – Fungal spores. • They are effective at preventing illness in individuals, when used both before and after exposure to the infective agent. • They could be used:  – Topically,  – As an inhalant.

27. Antimicrobial Nanoemulsion • Left: treated with nanoemulsion, • Right: untreated. • The growth of bacteria colonies has been eliminated by treatment with the nanoemulsion.

28. Example of Nanostructures:Starburst Dendrimers

29. What is a dendrimer? Branched polymers(dendron = tree in Greek)Functionality= 3 (Nitrogen)

30. Generations of Dendrimers Your Text Here

31. Generations of Dendrimers 2nd gen. 5th gen. 4th gen.

33. PAMAM Dendrimer (polyamidoamine) • Alternating (B)-AB-AB-AB-... • Ethylenediamine (B) • H2N-C-C-NH2 • Methylacrylate (A) • C=C-CO-OCH3

34. PAMAM Moieties: Diamine Acrylate NH3 or Diamine

36. Size of PAMAM DendrimersGeneration M.W. Angstrom (dia.) End Gps (1 nm = 10 Angstroms)

37. Equivalent Sizes with Cells:

38. Applications of Dendrimers • Gas and chemical sensors • Catalysts • Drug delivery and gene therapy • Surface modifiers (tribology, and information storage) • Bio compatible materials • Electronic devices and antennae

39. Dendrimers as Drug Delivery Agents:An Example

40. James R. Baker Jr. University of Michigan Professor, Internal Medicine and Bioengineering Chief, Division of Allergy Director, Center for Biologic Nanotechnology Co-Director, Center for Biomedical Engineering Biotechnology, Nanotechnology and Immunology

41. Drug Delivery • Research in the area of autoimmune endocrine disease. He has helped define the basis of the autoimmune response to thyroid auto antigens. Gene Delivery • Work concerning gene transfer; developing a new vector system for gene transfer using synthetic polymers (dendrimers). Anti-microbial research • Work on preventing pathogens from entering the human body. This research project seeks to develop a composite material that will serve as a pathogen avoidance barrier and post-exposure therapeutic agent to be applied in a topical manner to the skin and mucous membranes.

42. Receptors and Ligands

43. Dendrimers (code named “smart bombs”) Targeting cancer cells (ignore normal ones) Able to enter cells Little toxicity Focus: High energy lasers or sound wave to trigger the release of the drug out of the dendrimer. Drug Delivery by Dendrimers

44. Polyfunctional Tecto-dendrimers: (connected PAMAM units) • Each “spore” in this “smart bomb” has its function: • Sensing and binding the target (cancer cells). • Emitting a signal (imaging). • Drug delivery in situ. • Dendrimer’s structure tricks the immune system, avoiding response. • Low toxicity

45. Economist, Dec. 2001

46. Professor Chris Gorman:NCSU

47. Electron transfer dedndrimers

48. Example of Nanostructures:Aerogels

49. TEM of SiO2 Aerogels

50. Different aerogels: (95% air)