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MATERIALS ON THE NANO-SCALE FOR DIFFERENT APPLICATIONS M. A. El-Sayed Georgia Tech. OUTLINE 1.For Catalysis. 1.For Sensing. 2.For Medicine.

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Presentation on theme: "MATERIALS ON THE NANO-SCALE FOR DIFFERENT APPLICATIONS M. A. El-Sayed Georgia Tech. OUTLINE 1.For Catalysis. 1.For Sensing. 2.For Medicine."— Presentation transcript:

1 MATERIALS ON THE NANO-SCALE FOR DIFFERENT APPLICATIONS M. A. El-Sayed Georgia Tech. OUTLINE 1.For Catalysis. 1.For Sensing. 2.For Medicine.

2 NANO_PARTICLES FOR CATALYSIS 7.1 nm Cubes with {100} facets4.8 nm Tetrahedral with {111} facets Ahmadi, T.; Wang, Z. L.; Green, T. C.; Henglein, A.; El-Sayed, M. A., Science 1996, 272, 1924.

3 MORE REACTIVITY FOR ATOMS ON CORNERS AND EDGES Narayanan, R.; El-Sayed, M. A., Nano Lett., 2004, 4(7), Nanoparticle Shape Tetrahedral (~76%) Cubic (~61%) Spherical (~85%) Nanoparticle Size (nm) Fraction of Atoms On corners&edges Activation Energy (kJ/mol) Catalytic activity correlates with the fraction of atoms located on the corners and edges of the nanoparticles.

4 BY Photocatalysis in 50 nm Au Nanocage USING CHEMICAL CONFINEMENT IN NANO- CAGES ENHANCES THE CATALYTIC ACTIVITY (NANO-REACTORS). Application IN SOLVING Environmental problem

5 BULK GOLD IS PRECIOUS BECAUSE IT DOES NOTHING (it does not tarnish i.e. it does not react with O 2 ) Tutankhamuns coffin Death Mask of Tutankhamun ~1325 B.C.

6 Gold nanoparticles Plasmonic Properties on the NANOSCALE CAPTURING THE PHOTON TO INDUCE The Surface Plasmon RESONANCE (SPR) Oscillation with Strong Surface-Fields? light (520nm)Au Nanoparticle (50 nm) + 1.The Electromagnetic field of the captured Photon is Enhanced by Thousands of Times on the surface of the nanoparticle as a Result of the Coherent Oscillation Of the Collective Excitation of the Free Electrons in the Metal Cluster. 2. THIS Enhances The Rate of their Absorption (sensing) and Scattering (SERS;imaging and thus sensing) Proprties. 3.The Strongly Absorbed Energy is Rapidly Converted Into Heat That Can Have Useful Photo-Thermal Applications in Different Fields e.g medicine. near-field Capturing the photon photon

7 nm Optical tunability of gold nanorods Xiaohua Huang, Ivan H. El-Sayed and Mostafa A. El-Sayed, JACS, 2006, 125 (6), Gold or Silver Nanoparticles can Enhance the intensity of light of Different Colors by changing Their Size or Shape

8 100 nm Solid Silver Nanocubes Gold Nanoframes (BEST SENSOR) Gold Nanocages (BEST CATALYST) Hollow nanoparticles Hollow nanostructures characterized by the presence of two surfaces (and thus have two plasmon fields inside and outside the cage). The coupling between these two fields is responsible for enhancement of the overall plasmon field. They are then better sensors and BETTER OPTICAL LENSES'. The surface to volume ratio is higher for hollow nanoparticles than that for solid nanoparticles with the same outer shape and size. This together with their confining ability of the reactant and intermediates make them better catalysts (and drug carrier ) 8 solid Nancubes Mahmoud A Mahmoud

9 PLASMONIC FIELD ENHANCEMENT OF THE PHOTO-CURRENT FROM THE PROTON PUMP IN BACTERIO-RHODOPSIN; THE OTHER NATURAL PHOTO-SYNTHETIC SYSTEM CHUN-WAN YENLI-KANG CHU Yen, C.W.; Hayden, S.C.; Dreaden, E.C.; Szymanski, P.; El-Sayed, M.A., Tailoring Plasmonic and Electrostatic Field Effects to Maximize Solar Energy Conversion by Bacteriorhodopsin, the Other Natural Photosynthetic System. Nano Letters, 11(9), (2011 CITED By Nature Materials 10, 646 (2011). APPLICATION OF PLASMONIC OPTICAL ENHANCEMENT IN SOLAR ENERGY CONVERSION: STEVEN HAYDEN

10 Light-driven Proton Pump Electrochemical Energy (proton gradient) Very Low solar conversion efficiency Bacteriorhodopsin (bR): THE OTHER PHOTO- SYNTHETiC SYSTEM IN NATURE (besides Chlorophyll)

11 Blue Light Effect BLUE LIGHT FROM MEMBRANEINTO SOLUTION FROM MEMBRANE

12 Yen, C. W.; Chu, L-K.; El-Sayed, M. A. JACS, submitted Selection of the Nanoparticle with the best plasmonic enhancement of the M absorption (the best enhancement of the Blue Light Effect) Maximize The overlap of M state Absorption and SPR Extinction Of the nanoparticle: 1.Ag NPs: Green Spectrum, overlaps well With the Blue M absorption. 2Ag-Au alloy NPs: Orange Spectrum (Ag/Au=1/1): not as good 3.Au NPs: Red Spectrum Not good at all THE BEST OVERLAP WITH THE M ABSORPTION IS THE EXTINCTION SPECTRUM OF THE Silver NANOPARTICLE OF 30 nm SIZE.

13 Plasmonic Field Strength Dependence on Nanoparticle Shape 5000 times larger current than that reported in literature (with Bias Applied)

14 Charge carrier separation Least screening / Best stability(55k PVP) Highest field / Best spectral overlap (Ag Cuboidal) 0.2 μA/cm 3 (No Bias) Tailoring Plasmonic Electric Field Effects

15 APPLICATIONS IN MEDICINE

16 20 µm HaCaT noncancerous cells HOC cancerous cells HSC cancerous cells 10 µm Ivan El-Sayed,Xiaohua Huang,M.A.El-Sayed Nanoletters,4, 829,2005. DETECTION OF ONE CANCER CELL USING LIGH SCATTERING FROM SELECTIVELY BOUND GOLD NANO-PARTICLES USING A STUDENT MICROSCOPE DIFFRACTION UNLIMITTED IMAGING

17 UNTREATED I.V. Accumulation direct injection COMPARISON OF THE GROWTH RATE OF THE TREATED & THE UNTREATED TUMOR Dickerson, E. B.; Dreaden, E. C.; Huang, X.; El-Sayed, I. H.; Chu, H Dickerson, E. B.; Dreaden, E. C.; Huang, X.; El-Sayed, I. H.; Chu, H.; Pushpanketh, S.; McDonald, J. F.; El-Sayed, M. A. Cancer Letters 2008, 269, 57. ERIN HENDERSON

18 2.Confining Precious Metal(Au,Ag) Nanoparticles to the Cancer Nucleus: CAN IT STOP CELL DIVISION and thus stops cancer?? Lauren A. Austin Megan A. Mackey Bin Kang Chun-Wan Yen

19 DEFECTIVE CANCER CELL DIVISION FOR CELLS HAVING 0.4 NM GOLD IN THE NUCLEUS

20 Watching the Behavior of a Community of Dying Cancer Cells by binding Silver Nano-particles to their Nucleus

21 THANK YOU


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