BME 210 Lecture 19 Nanotechnology

BME 210 Lecture 19 Nanotechnology - 19. Nanotechnology...

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Unformatted text preview: 19. Nanotechnology History of nanotechnology The beginning - lecture in 1959 by Richard Feynman (1965 Nobel prize in physics) : There's Plenty of Room at the Bottom about possible advancements in technology. Main ideas: Reducing the size of information storage unit to few atoms; readout using electron microscope Reducing wires to dozens of atoms and computer circuits to <100 nm Re-arranging individual atoms to obtain new materials Assembling microscopic machines from individual atoms (e.g., microscopic surgical robots) Nanotechnology today Nanotechnology today is essentially a material science/technology The National Nanotechnology Initiative (2001) ( www.nano.gov ): Nanoscience involves research to discover new behaviors and properties of materials with dimensions at the nanoscale which ranges roughly from 1 to 100 nanometers (nm) The emphasis is on unique properties that are not exhibited by the same materials with a larger grain size. These new properties are primarily due to the quantum nature of electrons that become important at small scales Nanomaterials Nanoparticles: Quantum dots Nanoshells Magnetic nanoparticles Nanotubes Nanopores (filters, DNA sequencing) Nanolayers Nanowires Nanofibers Nanoarrays Nanocantelivers Nanoribbons Fullerenes Nanoshells Nanoshell : a nanoparticle with Silica core + metal (gold) shell core diameter 100 nm shell thickness 5-20 nm electrons in the gold shell strongly absorb light (due to the effect of surface plasmon resonance); the absorption spectrum is determined by the relative thickness of the shell and the core the absorbed energy is dissipated as heat Nanoshells can be used for tissue ablation using light (photothermal therapy) Nanoshell Absorption Shell thickness Core dia =120 nm Light used in photothermal therapy Tissue strongly absorbs visible light (mostly by water and hemoglobin) limiting depth of light penetration Optical window or NIR window - wavelength range with lowest light absorption by tissue: 700 - 900 nm (near-infrared) Photothermal nanoshell effect Tissue with nanoshells Tissue w/o nanoshells Laser 820 nm Nanoshells: Core = 110 nm Shell = 10 nm Increase of tissue temperature during laser radiation Nanoshell photothermal cancer therapy Subcutaneous tumors were grown in mice Nanoshells were injected intravenously; they accumulated in the tumors (due to the effect of enhanced permeability and...
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BME 210 Lecture 19 Nanotechnology - 19. Nanotechnology...

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