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Nanoscale Engineered Plasmonic Nanostructures for Biosensing and Bioimaging

Nanoscale Engineered Plasmonic Nanostructures for Biosensing and Bioimaging. Dr Fang Xie Department of Materials Imperial College London 7 th Asia Pacific Biotech Congress 13 th July 2015, Beijing, China. Imperial College London. Department of Materials. Overview. Plasmonic Materials.

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Nanoscale Engineered Plasmonic Nanostructures for Biosensing and Bioimaging

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  1. Nanoscale Engineered Plasmonic Nanostructures for Biosensing and Bioimaging • Dr Fang Xie • Department of Materials • Imperial College London • 7th Asia Pacific Biotech Congress • 13th July 2015, Beijing, China

  2. Imperial College London • Department of Materials

  3. Overview • Plasmonic Materials Healthcare Technologies Material Design Manipulating Light Engineered Material Fabrication Theoretical Simulation Solar Energy Harvesting • Large scale • Long range homogeneity • Tunable optical properties • Reproducibility

  4. Background: What is fluorescence? The father of fluorescence spectroscopy Image courtesy of Photomatrics • Jabłoński, Aleksander "Efficiency of Anti-Stokes Fluorescence in Dyes" Nature 1933, volume 131, pp. 839-840. • Jablonski diagram showing fluorescent absorption and emission processes.

  5. Background: What is plasmonic materials? • The optical properties of Nanoparticles—localized surface plasmon resonances (LSPRs): • Oscillations of the conduction electrons coupled to the E-field • The frequency and intensity of the oscillations are sensitive to the geometry and surrounding media Lycurgus Cup Reflection Transmission The artwork was crafted from glass stained with colloidal noble metal particles in the 4th Century; their strong interaction with visible light due to the excitation of LSPRs, gives rise to the vibrant green and red colours. Adv. Mater. 2007, 19, 3771–3782

  6. Background: How we use them for sensing/Imaging? Early Diagnosis by Metal Induced Fluorescence Enhancement Enhanced Fluorescence on metal nanostructured surface Fluorescence on glass surface Light interacting with a metal nanoparticle: the possible spectroscopic responses for sensitive biomolecular detection

  7. Fluorophore near Metallic particles Fluorophore in Free Space Condition Background: Mechanism of MIFE Metal Induced Fluorescence Enhancement: Fluorophores near metal nanostructures experience: • Greater quantum yields • Reduced lifetimes (b) Emission Enhancement (a) Excitation Enhancement E: excitation; Em: metal enhanced excitation rate; m:radiative rate in the presence of metal; Knr: non-radiative rate.

  8. Background: Mechanism of MIFE The effect of distance between metal surfaceand the fluorophore on MIFE: • 0 – 5 nm, quenching; • 5-20 nm, enhancement; • > 20 nm, free space fluorescence. Effect of metallic particle on fluorescence signal as a function of distance from particle Lakowicz et al. Analytical Biochemistry 301, 261–277 (2002)

  9. Nanostructures/Nanoparticles Fabrication/Synthesis

  10. Nanostructures by Nanosphere Lithography Polystyrene Monolayer Polystyrene Removed Substrate Metal Deposition • Physicochem. Eng. Aspects 219 (2003) 1 /6

  11. Metal Deposition PS Deposition and Shrink Argon Ion Milling PS Removal Nanostructures by Nanosphere Lithography Nanopillars Nanoholes Metal Deposition PS Deposition and Shrink PS Removal

  12. Nanostructures by Nanosphere Lithography

  13. Nanostructures by Synthesis

  14. Plasmonic Materials for Fluorescence Enhancement Investigation

  15. Au Core Ag-shell NP Surface 19 nm Glass Surface Au Colloid Surface 10 nm Au-Core Ag-shell NP Surface 47 nm Glass Surface Glass Surface F. Xie, M. Baker, E. Goldys, J. Phys. Chem. B 2006, 110, 23085-23091 A B C MIFE Substrates – bottom up methods 1) Au-core Ag-shell Nanoparticles: Method: Produce gold colloid and use silver enhancing step: 2AgNO3 + C6H4(OH)2 CO(CHCH)2CO + 2HNO3 + 2Ag 47 nm Au Core Ag-shell NP: Fluorescence enhancement of 10

  16. Metallic surface Glass surface Frequency (a.u.) Average Lifetime (ps) MIFE Substrates – bottom up methods 2) Au Nanoparticles: Au colloids of 40, 59, and 81 nm in Radius with 24 h incubation to form self-assembled layers on glass substrates. A colour coded lifetime image (FLIM) for the sample 161 nm Au – 24h SEM images (24 hours) of (A) 80 nm Au colloid; (B) 118 nm Au colloid; (C) 162 nm Au colloid. Distribution of the average lifetimes at the metallic surface and glass surface. Lifetime reduced on metal. F. Xie, M. Baker, E. Goldys, Chem. Mater 2008, 20, 1788-1797

  17. MIFE Substrates – top down method Two orders of fluorescence enhancement were observed for NIR dye by nano-engineering of Ag triangular arrays. F, Xie et al., Nano Res., DOI 10.1007/s12274‐013‐0327‐5

  18. MIFE Substrates – top down method Plots of e-field enhancement around the NPs at 780 nm, for (a) PS300 (b) PS500 (c) PS620 with 15s etching. Fluorescence spectra of Alexa Fluor 790 monolayer on sample PS300-15s (blue), PS500-15s (red), and PS620-15s (green) as well as on glass as control (black)

  19. MIFE Substrates – top down method Values of the Excitation Enhancement and Emission Enhancement for Each Sample Lifetime measurements for each sample and the calculated values of lifetime, radiative rate, and quantum yield ratios on metallic surfaces versus clean glass surface. (Q0 =10%)

  20. Plasmonic Materials for Protein Microarray

  21. MIFE biosensing Application – Protein Microarray Plasmonic gold-on-gold nano-island films enhance the fluorescence of near-infrared fluorophores. Enhancement factor for IR800: 16 Dai et al, DoI: 10.1038/ncomms1477

  22. MIFE biosensing Application – Protein Microarray Near-infrared fluorescence enhanced protein microarrays on gold substrates probed by IR800. • Sensitive enhancement: ~5000 fold; • Dynamic range: 6 orders of magnitude Model colon cancer biomarker: carcinoembryonic antigen (CEA), CEA sandwich bioassay probed by IR800. (excitation at 785 nm), CEA spiked into whole, undiluted serum

  23. MIFE biosensing Application – Protein Microarray Multiplexed Protein Microarray • Advantage of Plasmonic Au chip: • Increased feature intensities due to fluorescence enhancement • 10 fold lower background than Nitrocellulose • Additional auto-antigen features can be distinguished on plasmonic chip from the intensity heatmap. Broad dynamic range High sensitivity Multiplex capacity of using Plasmonic Chips: 32 human antigens and controls’ assay was printed (triplicated); Probed with IR800-conjugated goat anti-human IgG

  24. Plasmonic Materials for in vitro Bioimaging

  25. MIFE Application – Bioimaging in vitro live cell imaging – fluorescence enhancement by Au nanostructres Microplates hosting KB cells (oral cancer cell line) with Hoechst 33528 staining with the fluorescence enhancement being shown quantitatively (10 fold) Confocal images of a Au microplate hosting mouse 3T3 cells, stained with Alexa 488 for the acetylated histone H3 visualization Nano Res. 2010, 3(10): 738–747

  26. Nanoengineering of Plasmonic Material Fluorescence Enhancement for biosensing/bioimaging ~103 more sensitive Expected Detection limit: ~ Femtomolar range Current Detection limit: ~Picomolar range Glass slide Applications: ELISA, Protein Microarray, in vitro bioimaging in IR region II (1100 -1400 nm)

  27. Bioimaging Fluorescent Dyes in IR region II: Ag2S QDs and SWCNs Ag2S QDs • Benefit of working in NIR region II: • Increasing the sensitivity • Deeper penetration

  28. MIFE biosensing Application – Bioimaging In Vivo Fluorescence Imaging with Ag2S Quantum Dots in the Second Near-Infrared Region A steady increase of NIR-II fluorescence of 6PEGAg2S QDs in the tumor region and a decrease of NIR-II fluorescence in other organs and skin was observed from 30 min p.i. to 24 h p.i. Dai et al, DOI: 10.1002/ange.201206059

  29. MIFE technology – potential applications Plasmonic enhanced bioimaging using super bright NIR II probes? Plasmonic enhanced bioimaging and therapy ?? Clinical questions where MEF can help??

  30. Nanostructures by Nanosphere Lithography Sensing and in vitro bioimaging

  31. Nanostructures by Synthesis Superbrightin vivo bioimaging probes

  32. Acknowledgement Collaborators The research areas include electromagnetic modeling, light harvesting, bioengineering, synthetic biology, biomaterials, bioimaging, and biosensing.

  33. Acknowledgement Team members Ioannis Theodore (Postdoc); Jing Pang (PhD student); Daniel Price (PhD student); Heng Qin (PhD student); Zaynab Jaward (PhD student); Danyang Wang (MSc); Justin Lim (MEng); Amed Shamso (MSc)

  34. Thank you

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