WIKIBOOKS
DISPONIBILI
?????????

ART
- Great Painters
BUSINESS&LAW
- Accounting
- Fundamentals of Law
- Marketing
- Shorthand
CARS
- Concept Cars
GAMES&SPORT
- Videogames
- The World of Sports

COMPUTER TECHNOLOGY
- Blogs
- Free Software
- Google
- My Computer

- PHP Language and Applications
- Wikipedia
- Windows Vista

EDUCATION
- Education
LITERATURE
- Masterpieces of English Literature
LINGUISTICS
- American English

- English Dictionaries
- The English Language

MEDICINE
- Medical Emergencies
- The Theory of Memory
MUSIC&DANCE
- The Beatles
- Dances
- Microphones
- Musical Notation
- Music Instruments
SCIENCE
- Batteries
- Nanotechnology
LIFESTYLE
- Cosmetics
- Diets
- Vegetarianism and Veganism
TRADITIONS
- Christmas Traditions
NATURE
- Animals

- Fruits And Vegetables



ARTICLES IN THE BOOK

  1. Atomic force microscope
  2. Atomic nanoscope
  3. Atom probe
  4. Ballistic conduction
  5. Bingel reaction
  6. Biomimetic
  7. Bio-nano generator
  8. Bionanotechnology
  9. Break junction
  10. Brownian motor
  11. Bulk micromachining
  12. Cantilever
  13. Carbon nanotube
  14. Carbyne
  15. CeNTech
  16. Chemical Compound Microarray
  17. Cluster
  18. Colloid
  19. Comb drive
  20. Computronium
  21. Coulomb blockade
  22. Diamondoids
  23. Dielectrophoresis
  24. Dip Pen Nanolithography
  25. DNA machine
  26. Ecophagy
  27. Electrochemical scanning tunneling microscope
  28. Electron beam lithography
  29. Electrospinning
  30. Engines of Creation
  31. Exponential assembly
  32. Femtotechnology
  33. Fermi point
  34. Fluctuation dissipation theorem
  35. Fluorescence interference contrast microscopy
  36. Fullerene
  37. Fungimol
  38. Gas cluster ion beam
  39. Grey goo
  40. Hacking Matter
  41. History of nanotechnology
  42. Hydrogen microsensor
  43. Inorganic nanotube
  44. Ion-beam sculpting
  45. Kelvin probe force microscope
  46. Lab-on-a-chip
  47. Langmuir-Blodgett film
  48. LifeChips
  49. List of nanoengineering topics
  50. List of nanotechnology applications
  51. List of nanotechnology topics
  52. Lotus effect
  53. Magnetic force microscope
  54. Magnetic resonance force microscopy
  55. Mechanochemistry
  56. Mechanosynthesis
  57. MEMS thermal actuator
  58. Mesotechnology
  59. Micro Contact Printing
  60. Microelectromechanical systems
  61. Microfluidics
  62. Micromachinery
  63. Molecular assembler
  64. Molecular engineering
  65. Molecular logic gate
  66. Molecular manufacturing
  67. Molecular motors
  68. Molecular recognition
  69. Molecule
  70. Nano-abacus
  71. Nanoart
  72. Nanobiotechnology
  73. Nanocar
  74. Nanochemistry
  75. Nanocomputer
  76. Nanocrystal
  77. Nanocrystalline silicon
  78. Nanocrystal solar cell
  79. Nanoelectrochemistry
  80. Nanoelectrode
  81. Nanoelectromechanical systems
  82. Nanoelectronics
  83. Nano-emissive display
  84. Nanoengineering
  85. Nanoethics
  86. Nanofactory
  87. Nanoimprint lithography
  88. Nanoionics
  89. Nanolithography
  90. Nanomanufacturing
  91. Nanomaterial based catalyst
  92. Nanomedicine
  93. Nanomorph
  94. Nanomotor
  95. Nano-optics
  96. Nanoparticle
  97. Nanoparticle tracking analysis
  98. Nanophotonics
  99. Nanopore
  100. Nanoprobe
  101. Nanoring
  102. Nanorobot
  103. Nanorod
  104. Nanoscale
  105. Nano-Science Center
  106. Nanosensor
  107. Nanoshell
  108. Nanosight
  109. Nanosocialism
  110. Nanostructure
  111. Nanotechnology
  112. Nanotechnology education
  113. Nanotechnology in fiction
  114. Nanotoxicity
  115. Nanotube
  116. Nanovid microscopy
  117. Nanowire
  118. National Nanotechnology Initiative
  119. Neowater
  120. Niemeyer-Dolan technique
  121. Ormosil
  122. Photolithography
  123. Picotechnology
  124. Programmable matter
  125. Quantum dot
  126. Quantum heterostructure
  127. Quantum point contact
  128. Quantum solvent
  129. Quantum well
  130. Quantum wire
  131. Richard Feynman
  132. Royal Society's nanotech report
  133. Scanning gate microscopy
  134. Scanning probe lithography
  135. Scanning probe microscopy
  136. Scanning tunneling microscope
  137. Scanning voltage microscopy
  138. Self-assembled monolayer
  139. Self-assembly
  140. Self reconfigurable
  141. Self-Reconfiguring Modular Robotics
  142. Self-replication
  143. Smart dust
  144. Smart material
  145. Soft lithography
  146. Spent nuclear fuel
  147. Spin polarized scanning tunneling microscopy
  148. Stone Wales defect
  149. Supramolecular assembly
  150. Supramolecular chemistry
  151. Supramolecular electronics
  152. Surface micromachining
  153. Surface plasmon resonance
  154. Synthetic molecular motors
  155. Synthetic setae
  156. Tapping AFM
  157. There's Plenty of Room at the Bottom
  158. Transfersome
  159. Utility fog

 



NANOTECHNOLOGY
This article is from:
http://en.wikipedia.org/wiki/Surface_plasmon_resonance

All text is available under the terms of the GNU Free Documentation License: http://en.wikipedia.org/wiki/Wikipedia:Text_of_the_GNU_Free_Documentation_License 

Surface plasmon resonance

From Wikipedia, the free encyclopedia

 

The excitation of surface plasmons by light is denoted as a surface plasmon resonance (SPR) for planar surfaces or localized surface plasmon resonance (LSPR) for nanometer-sized metallic structures.

Explanation

Surface plasmons, also known as surface plasmon polaritons, are surface electromagnetic waves that propagate parallel along a metal/dielectric interface. For electronic surface plasmons to exist, the real part of the dielectric constant of the metal must be negative and its magnitude must be greater than that of the dielectric. This condition is met in the IR-visible wavelength region for air/metal and water/metal interfaces (where the real dielectric constant of a metal is negative and that of air or water is positive). Electronic and magnetic surface plasmons obey the following dispersion relation:

K(\omega) = \frac{\omega}{c} \sqrt{\frac{\epsilon_1 \epsilon_2 \mu_1 \mu_2}{\epsilon_1 \mu_1 + \epsilon_2 \mu_2}}

Typical metals that support surface plasmons are silver and gold, but metals such as copper, titanium, or chromium can also support surface plasmon generation. Surface plasmons have been used to enhance the surface sensitivity of several spectroscopic measurements including fluorescence, Raman scattering, and second harmonic generation. However, in their simplest form, SPR reflectivity measurements can be used to detect DNA or proteins by the changes in the local index of refraction upon adsorption of the target molecule to the metal surface. If the surface is patterned with different biopolymers, the technique is denoted as Surface Plasmon Resonance Imaging (SPRI).

For nanoparticles, localized surface plasmon oscillations can give rise to the intense colors of solutions of plasmon resonance nanoparticles and/or very intense scattering. Nanoparticles of noble metals exhibit strong ultraviolet-Visible absorption bands that are not present in the bulk metal. Shifts in this resonance due to changes in the local index of refraction upon adsorption of biopolymers to the nanoparticles can also be used to detect biopolymers such as DNA or proteins. Related complimentary techniques include plasmon waveguide resonance, QCM and Dual Polarisation Interferometry

Binding constant determination

SPR setup
SPR setup
Association and dissociation signal
Association and dissociation signal

When the affinity of two ligands has to be determined, the binding constant must be determined. It is the equilibrium value for the product quotient. This value can also be found using the dynamical SPR parameters and, as in any chemical reaction, it is the association rate divided by the dissociation rate.

For this, a so-called bait ligand is coated to the gold surface of the SPR crystal. Through a microflow system, a solution with the prey ligand can flow over the bait layer and bind. Binding will make the SPR signal change to an equilibrium. After some time, a solution without the prey is applied, and a new equilibrium will be reached. From these association ('on rate', von)and dissociation speeds ('off rate', voff), the binding constant can be calculated.

The actual SPR signal can be explained by the electromagnetic 'coupling' of the incident light with the surface plasmon of the gold layer. This plasmon can be influenced by the layer just a few nanometer across the gold-solution interface i.e. the bait protein and possibly the prey protein. Binding makes the reflection angle change.;

K = \frac{v_{off}}{v_{on}}

Magnetic Plasmon Resonance

Recently, there has been an interest in magnetic surface plasmons. These require materials with large negative magnetic permeability. A property that has only recently been made available with the construction of metamaterials. The only reported demonstration of magnetic plasmon resonance has been at Duke University.

References

  • Hutter E, Fendler J. Exploitation of Localized Surface Plasmon Resonance. Adv. Mater. 2004, 16, 19, 1685-1706.
  • Aslan K, Lakowicz JR, Geddes C. Plasmon light scattering in biology and medicine: new sensing approaches, visions and perspectives. Current Opinion in Chemical Biology 2005, 9:538–544
  • Smith EA, Corn RM. Surface Plasmon Resonance Imaging as a Tool to Monitor Biomolecular Interactions in an Array Based Format. Appl. Spectroscopy, 2003, 57, 320A-332A.
  • H. Raether, Surface plasmons on smooth and rough surfaces and on gratings (Springer Verlag, Berlin, 1988)
  • J. N. Gollub, D. R. Smith, D. C. Vier, T. Perram, J. J. Mock, Phys. Rev. B 71, 195402 (2005)

See also

  • Hydrogen microsensor
  • Plasmon
  • Nano-optics
Retrieved from "http://en.wikipedia.org/wiki/Surface_plasmon_resonance"