How Optics Plays a Role in Soft Matters ? ( Colloids and Lipids )

1. How OpticsPlays a Role in Soft Matters?(Colloids and Lipids ) School of Electrical Engineering Seoul National University, Korea Sin-Doo Lee

2. Outline • Introduction: Optics Meets Soft Matter • Optical Detection/Manipulation Tools for Soft Matters • Soft Matter-Based Optical Applications • Nano-Network Assembly of Colloidal Particles • Fundamentals of Structural Self-Organization • Optical Antenna and Nano-Slit Applications • Plasmonic Detection of Biological Activities • Periodic Metal Nanostructures (Nanosphere Lithography) • Specific Protein-Binding on Lipid Membranes • Plasmonic Detection (Localized SPR) • Summary

3. Introduction: OpticsMeetsSoft Matters At Mesoscopic Scale Optics • Optical Tools • (Manipulation & Detection) • Optical Phenomena • (Electro-Optic, Plasmonic) Soft Matters • Liquid Crystals • Colloids • Lipid Membranes • (Biomolecules) • Micelles, Polymers, etc Novel Applications • Photonic Crystals, Optoelectronics • New Biosensors (Plasmonic) • Lithographic & Biomimic Tech • (Particle Litho., Structural Colors) • Optics provides - a versatile tools of manipulating soft matters and • - new phenomena for developing novel devices!

4. Optical Tools: Manipulation & Detection • Optical Tweezer for Colloidal Particles For review, Nature 424, 21 (2003) • Strongly focused beam of light to trap individual objects. • Manipulation of colloidal particles by trap and de-trap using focused beam of light.

5. Opto-Electronic Tweezer for Biological Cells: Optical E -> Static E Nature 436, 370 (2005) • Focused beam of light to produce non-uniform electric field through digital • micromirror display on photosensitive surface for dielectro-phoresis (DEP). • Upon DEP, only living cells can be pulled into the pattern’s center.

6. Optical Phenomena: Plasmonic Effect • Plasmonics in Nanostructures (wire, shell, rice, disk, star, etc) Downsizing Beyond Wavelength Metallic Nanostructures ??? (Surface Plasmon) Nano Lett. 10, 3816 (2010)

7. Detection of Biological Activity Anal. Chem. 81, 2564 (2009) J. Phys. Chem. C 115, 1410 (2011) • Extinction of localized SPR depends dielectric environment of surrounding. • Peak wavelength shift by protein (CTB, anti-biotin) binding, resulting in • the dielectrically modified environment near the metal nano-objects.

8. New Applications: Photonics, Biomimetics • Photonic Crystals of Colloidal Particles Mater. Future 8, 8 (2009) Angew. Chem. 119, 7572 (2007) • The photonic band-gap can be tuned the size, shape, and interparticle distance • (lattice) and/or external fields (magnetic, tension) in colloidal crystal structures.

9. Mimicking Colorful Wing Scale Structure 2D colloidal crystal for template Nature Nanotech. (2010, online, May) • Fabrication of artificial optical mimic, showing different colors of light reflected • from different regions of scales, using colloidal particle template.

10. Lipid Multilayer Gratings Nature Nanotech. 5, 275 (2010) • Lipid multilayer grating using dip-pen nanolithography. • Used for label-free and specific detection of lipid–protein interactions in solution.

11. Particle Lithography 3D Nanolithography Nanosphere Lithography Talbot Effect J. Phys. Chem. B 105, 5599 (2001) Nano Lett. 11, 2533 (2011) • Fabrication of metal nanostructures • using colloidal particle mask during • metal deposition

12. Nano-Network Assemblies of Colloidal Particles • Colloidal Networks by Polymorphic Meniscus Convergence Adv. Mater. 22, 4172 (2010) • Hydrophobic substrate with air-cavity on hydrophillic support • Lines, networks (X or Y) of nanoparticles due to polymorphic meniscus convergence • Cell gap determines whether mono-layer or double-layer is energetically favorable • Symmetry of colloidal networks depends the flow direction and the cavity shape

13. Optical Antenna & Nano-Slit Using Nanosphere Assembly • Colloidal particle array as a mask for metal deposition • Optical antenna: direction-specific activationof metallic half-shell antenna • Optical nano-slit: the output through subwavelength slit of dielectric disks • depends on the polarization of input white light

14. Optical Antenna: a device that converts freely propagating optical radiation • into localized energy and vice versa. Nature Photon. 5, 83 (2011) • the ability to control and manipulate optical fields at the nanometer scale • potential for enhancing the performance and the efficiency of photodetection, light • emission, light harvesting, and sensing

15. - Terahertz Field Enhancement by Metal Nano-Slit: Nature Photon. 3, 152 (2009) • Two important length scales: wavelength, the skin depth of metal • Metallic nanostructures as sub-skin depth field-enhancing and focusing devices for • terahertz operations

16. Optical Detection of Biological Activity • Plasmonic Detection by Randomly Distributed Nano-Cubes Nano Lett. 9, 2077 (2009) • The peak shift results from the difference in the SPR due to protein- binding • - Δλmax(nonspecific, bovine cerium albumin) = 0.03 nm,Δλmax(specific, neutravidin) = 1.26 nm • Effect of random distribution and the size of nano-cubes on the number of peaks • and the broadening ?

17. Effect of Metal Dimension & Periodicity ? • Effect of Separation, Size, Shape, etc - Theoretical Works for Sphere, Truncated Tetrahedron J. Phys. Chem. B 103, 2394 (1999) Opt. Comm. 220, 137 (2003) • Longer (or shorter) wavelength and broadening for p (or s)-wave at smaller separation

18. SLM on Ordered Nanostructures of Metal 1. Self-organized assembly of colloidal crystals from a solution on a quartz substrate by convective process 2. Deposition of metal and removal of colloidal particles by sonication 3. SLM formation on the substrate with periodic, metal nanostructures by vesicle adsorption & rupture 4. Protein binding detected by the localized SPR • Nanosphere lithography using PS particles of 300 nm • and 500 nm in diameter • - lateral size of the metal patterns: 70 nm, 116 nm • Periodic and well-defined separation of metal • nanostructures To be published (2011)

19. Fluidity of SLM by FRAP 100 um • DOPC lipids doped with • - biotin-DPPE for binding with streptavidin or streptavidin conjugated with Alex Fluor • - Tex Red-DHPE for imaging • Small unilamellar vesicles by extrusion • SLM formation by vesicle adsorption/rupture • FRAP (fully recovered after 20 min): confirmation of the fluidity of SLB • Specific protein-binding events occurs uniformly

20. Plasmonic Detection of Specific Protein-Binding - Metallic Nano-Patterns (70 nm) by Particles of 300 nm Peak positions in spectrum (not normalized) - Water : 677nm - Membrane : 687nm - Avidin binding : 689nm • Peak in the extinction spectrum of the localized SPR signal • - Increase of the dielectric constant of the surrounding of metallic nano-patterns • (water, membrane, and specific protein binding) • - λmax (water) = 677 nm, Δλmax(membrane) = 10 nm, Δλmax(avidin) = 2 nm • Larger peak shift than randomly distributed metal nanostructures • - Possibility of higher sensitivity?

21. - Metallic Nano-Patterns (116 nm) by Particles of 500 nm Peak positions in spectrum (not normalized) - Water : 723nm - Membrane : 734nm - Avidin binding : 736nm • Peak in the extinction spectrum of the localized SPR signal • - λmax (water) = 723 nm, Δλmax(membrane) = 11 nm, Δλmax(avidin) = 2 nm • λmax (water) becomes longer with increasing the size of metal nanostructures • and the separation between them • but the magnitude of the peak shift due to specific binding remains same !

22. IV. Summary • What Expected When Optics Meets Soft Matters? • Soft Matters for Optics: • Discover new optical phenomena from the complexity and • the flexibility of soft matters (at mesoscopic scale) • Open a door to a wide range of applications in photonics, • opto-electronics, nano-bio sensors, etc. • Opticsfor Soft Matters: • Provide methodology for optical detection/manipulation • of soft matters • Enable to develop bottom-up technology for integrating basic • building units • Establish a new paradigm of probingbiological activities