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Nanostructures and its Applications

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1 Nanostructures and its Applications
N. Ponpandian Department of Nanoscience and Technology Bharathiar University Coimbatore Web:

2 electron = h / p “De Broglie’s Relationship”
ELECTRON WAVES Separate NanoSCIENCE from MicroSCIENCE The discovery that electrons = waves led to QUANTUM MECHANICS A weird, new, counter intuitive, non-Newtonian way of looking at the nano world With a particular impact upon our understanding of electrons: Electrons => Waves How do you figure out an electron’s wavelength? electron = h / p “De Broglie’s Relationship” ( = electron wavelength, h = Planck’s Constant, p = electron’s momentum) This relationship was based on series of experiments late 1800’s / early 1900’s To put the size of an electron’s wavelength in perspective: 2

3 Planck’s Wavelength  = h/p (or) h/mv
Quantum Mechanics Planck’s Wavelength  = h/p (or) h/mv When mv >> h – Quantum effects are not observables mv ~ h - Quantum effects are observable 3

4 How to see the Nanoparticles?

5 Size of Things (red = man-made things)
Millimeters Microns Nanometers Ball of a ball point pen 0.5 Thickness of paper Human hair – 200 Talcum Powder 40 Fiberglass fibers Carbon fiber 5 Human red blood cell 4 – 6 E-coli bacterium 1 Size of a modern transistor Size of Smallpox virus – – 300 ___________________________________________________________________________________________________ Electron wavelength: ~10 nm or less Diameter of Carbon Nanotube 3 Diameter of DNA spiral 2 Diameter of C60 Buckyball Diameter of Benzene ring Size of one Atom ~0.1

6 Surface Area in Nanomaterials
A = 4 x 2 a x a + 2 a2 = 8 a2 + 2 a2 = 10 a2 A = 6 x a x a + 6 a x a = 12 a2

7 Surface Area in Nanomaterials

8 Surface Area in Nanomaterials

9 Surface Area in Nanomaterials

10 Surface Energy Surface atoms posses more energy than bulk atoms
Consequently, surface atoms are more chemically reactive Nanoparticles posses enhanced chemical reactivity Example: NASA is exploring aluminum nanoparticles for rocket propulsion due to their explosiveness.

11 Nanoparticle Catalysis Research Group, Tsukuba, Japan
Macroscopic Gold is chemically inert. Gold nanoparticles are used to catalyze chemical reactions. Example: Reduced pollution in oxidation reactions (i.e., environmentally friendly Nanoparticle Catalysis Research Group, Tsukuba, Japan

12 Macroscopic melting temperature
At macroscopic length scales, the melting temperature of materials in size-independent. For example, an ice cube and a glacier both melt at the same temperature (32˚ F)

13 Nanoscale melting temperature
Nanocrystal size decreases Surface energy increases Meling point decreases Example: 3 nm CdSe nanocrystal melts at 700 K compared to bulk CdSe at 1678 K

14 Optical absorption  = hc/Eg

15 What are Quantum dots? Types of materials Metals – No band gap Semiconductors – low band gap Insulators – very high band gap

16 What are Quantum dots? Quantum dots are nanocrystals of semiconductors that exhibit quantum confinement effects, once their dimensions get smaller than a characteristic length, called the Bohr’s radius. This Bohr’s radius is a specific property of an individual semiconductor Bohr’s radius can be equated with the electron–hole distance in an exciton that might be formed in the bulk semiconductor.

17 What is special in QDs towards nm
Below this length scale (Bohr’s radius) the band gap (the gap between the electron occupied energy level, similar to HOMO, and the empty level, similar to LUMO), which are is size-dependent. Band gap is Size Dependent Valence band Conduction band towards nm

18 Mechanical Properties - CNT
Structural differences Nanoscale Carbon Bulk Carbon C60 (Buckeyball) Smalley, Curl, Kroto 1996 Nobel Prize Graphite Diamond Carbon Nanotubes Sumio Iijima

19 What makes CNTs different from one another?

20 Physics of carbon nanotube

21 CNT – Field emission displays

22 Fe filled MWCNT: Bio-compatible nanomagnets

23 Fe filled MWCNT: Bio-compatible nanomagnets

24 Magnetism

25 Automative Magnetics

26 A technology which impacts the environment !

27 Hysteresis Loop

28 Hysteresis Loop

29 Ferromagnetic Domains

30 ? Effect of nanosize on magnetic property D
Why nanocrystalline materials t of have excellent soft magnetic properties D Lex Random Anisotropy Model ? Grain size > exchange length soft magnetic properties  as grain size  Grain size < exchange length soft magnetic properties  as grain size 

31 Magnetic properties of nanostructured materials

32 Superparamagnetism Response of superparamagnets to applied field described by Langevin model Qualitatively similar to paramagnets At room temperature superparamagnetic materials have a much greater magnetic susceptibility per atom than paramagnetic materials

33 Biomedical Applications of Magnetic Nanoparticles

34 Magetism and medicine Iron and living things
Many animals use magnetic fields to navigate Synthesize hemoglobin Role of iron in neurodegenerative disease Medical applications Removal of iron splinters, shrapnel, etc. Holding prosthetics Guiding instruments through the body MRI

35 Magnetic heating (Hyperthermia) Targeted drug delivery
Biomedical applications of magnetic nanoparticles Magnetic imaging Magnetic heating (Hyperthermia) Targeted drug delivery Detection/purification/isolation Manipulation

36 Magnetic Sorting Goal: Separate/detect/isolate one type of cell from others, often when the target is present in very small quantities

37 Magnetic Sorting, Detection
Functionalized nanoparticles R Ligand O -

38 Magnetic Sorting Add to Samples Cells

39 Magnetic Sorting Magnetic nanoparticles bond with targeted cells

40 Magnetic Sorting Retain desired cells by applying a magnetic field

41 Hyperthermia Cancer cell growth is slowed or stopped at 42 °C - 46 °C
Magnetic materials inside the body generate heat due to Hysteresis Brownian motion Eddy currents Nanoparticles provide uniform heating non-invasive delivery multiple treatments Human clinical trials in progress (Germany)

42 Magnetic Hyperthermia for Cancer Treatment

43 Magnetic resonance imaging
Non-invasive method used to render images of the inside of an object Primarily used in medical imaging to demonstrate pathological or other physiological alterations of living tissues MRI is currently the most efficient imaging procedure used in medicine

44 Typical MRI device

45 Typical MRI images

46 Problems in MRI Low contrast between different tissues
Low contrast between a healthy tissue and tumors

47 Contrast agents Different contrast agents are administered in 40–50% of all MR examinations in order to improve the efficiency of this procedure Contrast agents are diagnostic pharmaceutical compounds containing paramagnetic or superparamagnetic metal ions or nanoparticles that affect the MR-signal properties of surrounding tissues Gadolinium chelates are the most widely used extracellular, non-specific contrast agents Organ specific contrast agents include superparamagnetic iron oxides nanoparticles stabilized with appropriate biopolymers or biocompatible synthetic polymers

48 Used for intravenous applications
Clinically approved superparamagnetic contrast agents stabilized with biopolymers Ferumoxide (Endorem, Feridex)  dextran stabilized Ferumoxtran (Sinerem, Combidex)  dextran stabilized Ferucarbotranum (Resovist)  carboxydextran stabilized Used for intravenous applications

49 MRI of liver tumor After SPIO application Normal liver tissue contains phagocytic Kupffer cells  darkening after dextran-coated SPIO application Cancer cells do not contain Kupffer cells  after dextran-coated SPIO application tumor is brighter that surrounding tissue Before SPIO application

50 MRI of gastrointestinal tract
Oral application of superparamagnetic nanoparticles Small bowel before (left) and after (right) application of the oral contrast agent

51 Commercially available contrast agents:
MRI of gastrointestinal tract Commercially available contrast agents: Ferumoxsil (GastroMARK, Lumirem)  silicon-coated superparamagnetic iron oxide Ferristene (Abdoscan)  sulphonated styrene-divinylbenzene latex particles (Ø 3.5 μm) with bound superparamagnetic nanoparticles

52 Nanomedicine


54 Nanomedicine : An Overview
Nanomedicine is an interdisciplinary field of science, even a simple project needs contributions from physicists, engineers, material chemists, biologists and end users, such as an orthopaedic surgeon. A mature nanomedicine will require the ability to build structures and devices to atomic precision, hence molecular nanotechnology and molecular manufacturing are key enabling technologies for nanomedicine. Medicine must catch up with the technology level of the human body before it can become really effective. The result will be the ability to analyse and repair the human body as completely as we can repair a conventional machine today. If the nanoconcept holds together, it could be the groundwork for a new industrial revolution. BUT: can all different scientists and engineers work together to achieve crossover dreams?

55 History Despite the importance of nanotechnology, literature review of robotics in 1993 included not a single reference to nanotechnology or nanomedicine. The first nanomedical device design technical paper in 1998 by Freitas: Respirocyte – an Artificial Red Cell.

56 Nanostructures in Nature
Nature has created nanostuctures for billenia. Biological systems are an existing proof of molecular nanotechnology. Biology is an ingenious form of nanotechnology, even very simple living cells are able to duplicate. So far there is no machine of any size or type, which could do the same.

57 Replication Replication is a basic capability for molecular manufacturing. Still some scientists think that medical nanorobots need not ever replicate. It is unlikely that the FDA would ever approve a use of a medical nanodevice that was capable of in vivo replication. Replicators will be very tightly regulated by governments everywhere. In practice you would not want anything that could replicate itself to be turned loose inside your body.

58 Nanodreams Nanomedicine will eliminate virtually all common diseases, all medical pain and suffering => theoretically eternal life. Extension of human capabilities. New era of peace. People who are well-fed, well-clothed, well-educated, healthy and happy will have little motivation to make war. Pollution-free industry will guarantee the well-being for the nature.

59 Nanohorrors Self replicating nanorobots could become massive chemical and biological weapons. Changes to human properties, such as brains, respiration, muscles and DNA will be uncontrolled and may threat the existence of human being.

60 Potential Applications of Nanomedicine

61 Human Targets

62 Drug Delivery I Nanoparticles can deliver drugs in a sophisticated ways, like target specific and trigger based drug dose. Target specific delivery enables the use of lower doses, because the whole body is not saturated with the drug. The side effects will be minimized, and it is possible to use stronger drugs, which could not be used by conventional drug delivery. The use of gold particles in cancer healing is an example target specific action. Gold plated spheres are linked to tumor cells. Nanoshells can be heated from the outside using an infrared source. Heating the shells destroy the cancerous cells, leaving the surrounding tissue unharmed.

63 Improved Imaging Using magnetic nano particle can Improve imaging with better contrast agents and helps to diagnose diseases more sensitively. The method enables the detection of very small tumors and other organisms which cause disease. When the diagnostics is improved the healing will also be easier.

64 DNA Analyses Semiconductor nanocrystals, quantum dots, absorb only photons of light omitting just the right wavelength for their size. Use of a variety of sizes and concentrations of quantum dots produces a spectral bar code with distinct spectral lines. Such method allows multiple labels. Fast and accurate DNA testing, comparison of genetic material, rewriting DNA sequences in vivo, and even home DNA test systems.

65 Nanobarcode® Technique I
SurroMed company is developing nanobarcode® technique with researchers from the Penn State University. The idea is to use little metallic bars. Consecutively alternating gold- and silver-bands on a bar are interpreted as individual bits. Twenty bands equal twenty bits ≈ 106 alternatives. The bands can be interpreted with an optical microscope.

66 Nanobarcode® Technique II
Numerous DNA-testers can be attached to a single bar, the testers combine with receptor molecules. The complex formation results a multiple DNA-sequence analysis. Also antibody molecules can be attached to a surface of a bar, after an immunologic reaction peptide hormones can be analysed. Hundreds of components can be measured from one milliliter of serum, multiple test tubes and plentiful blood samples become unnecessary.

67 Superior Implant Materials
The connection between implant material and bone/ surrounding tissues is a key factor to a successful and long-term use of prostheses. Nano-scale modifications of implant surfaces would improve implant durability and biocompatibility.

68 Cleaning Robots I Teeth cleaning robots collect harmful bacteria from the mouth.

69 Cleaning Robots II Similar cleaning robots can be used in lungs. We have natural macrophages in alveoli, but they are not able to metabolize foreign particles like fibers of asbestos and toxic effects of smoking from the lungs.

70 Cleaning Robots III Extra fat can be removed from the arteries with cleaning robots.

71 Respirocyte It is an artificial mechanical red blood cell floating along in the bloodstream. A spherical (d = 1 μm) nanomedical device is made of 18*109 atoms (mostly carbon). The design of respirocyte was the first technical paper on nanomedical device design. It was published in 1998 by Robert A. Freitas. It is important to notice that molecular nanotechnology violates no physical laws and there are technical paths leading to useful results. Respirocyte device cannot be built today

72 Improving Brains A nanostructured data storage device measuring a volume about the size of a single human liver cell can store an amount of information equivalent to the entire library.

73 Artificial Tissues and Organs
Researchers hope to figure out ways to regenerate skin, bone and more sophisticated organs. At present auto-, allo- and xenografts plus some artificial materials are being used for reconstruction of damaged tissues and organs. The amount of auto- and allografts is limited, and allo- and xenografts carry a risk of infection (HIV or BSE). So the need and interest for artificial regeneration definitely exists!

74 Properties of Medical Nanodevices
Shape and size Biocompatibility Powering Communication Navigation

75 Modern Storage Devices
Magnetic Thin Films for Modern Storage Devices

76 The Nobel Prize in Physics 2007
for the discovery of Giant Magnetoresistance Albert Fert Université Paris-Sud Unité Mixte de Physique CNRS/THALES Orsay, France Peter Grünberg Forschungszentrum Jülich Jülich, Germany

77 The first step of spin electronics

78 Magnetic Trilayers Trilayer is a prototype to study magnetic interlayer exchange coupling. System Studied : Co/Cu/Ni/Cu(100) Two trivial limits: (i) dCu = 0  direct coupling (Ni-Co alloy) (ii) dCu = large  no coupling (NiCo powder) Objectives: To study the interlayer exchange coupling effects between the magnetic layers as a function of the thickness of Cu and Ni layers A. Scherz, S. Sorg, M. Bernien, N. Ponpandian et. al. , Physical Review B 72 (2005)

79 Ferromagnetic coupling Antiferromagnetic coupling
Magnetic Trilayers in Current Technology Ferromagnetic coupling Resistance = low FM1 FM2 Antiferromagnetic coupling Resistance = high

80 MRAM = Fast + Dense + Non-Volatile
Why MRAM? MRAM combines Silicon technology & Magnetic thin film technology To acheive Fast, Dense, Non-Volatile Solid state memory DRAM MRAM = Fast + Dense + Non-Volatile SRAM Flash

81 Effect of Interlayer Exchange Coupling
XMCD probe the sign of Jinter Excellent agreement between experiment and theory in TC shift A. Scherz, S. Sorg, M. Bernien, N. Ponpandian et. al. , Physical Review B 72 (2005)

82 Switching in Fe-Porphyrin
Why Organic Molecules? Miniaturization of information storage system Organic semiconductors have been used to fabricate promising devices such as OLEDs, FETs and photovoltaic cells Organic molecules contain only lighter elements and so Spin – orbit coupling is minimal transport of spin-polarized current over long distances Objectives: To combine organic semiconductors with magnetic materials to develop novel devices such as MMRAM and MMSDs MMRAM – molecular magnetic random access memory MMSDs – molecular magnetic spin devices

83 Fe-octaethylporphyrin chloride (Fe-OEP) molecule
Fe-Porphyrin Thermally and chemically stable Chemical properties can be modified through synthesis with different ‘centre atom‘ and substituent groups Present Study: To asses the orientation of the Fe OEP molecules on the surfaces of ferromagnetic Ni (or) Co type of magnetic ordering the magnetic orientation Sytem Studied: Fe-porphyrin/15ML Ni (or) 5 ML Co on Cu(100) Fe-octaethylporphyrin chloride (Fe-OEP) molecule Nature Materials 6, (2007)

84 Orientation of Fe-Porphyrin
Angular dependent NEXAFS * * Corbon K-edge Nitrogen K-edge Same fine structures (Co and Ni) Very similar absorption geometry Normal incidence - * resonance dominates Grazing incidence - * resonance dominates From N K–edge - molecules are intact with surfaces Plane of the four nitrogen atoms are aligned parallel to the surafce Nature Materials 6, (2007)

85 Commercial Applications

86 Thank you for your attention
Questions Please !!!

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