PCF with immobilized silver nanoparticles as an optofluidic SERS sensing platform

The unique feature of photonic crystal fiber (PCF) both as a light guide and a liquid transmission cell allows synergistic integration of optics and microfluidics to form an unconventional optofluidic platform of long interaction path limited only by the fiber length. We report the strategy and methods in realizing full-length surface-enhanced Raman scattering (SERS) PCF optofluidics by immobilization of negatively charged Ag nanoparticles (NP) through polyelectrolyte-mediated approach or direct deposition of positively charged Ag NP on the PCF air channels. Through forward propagating Raman measurements, we demonstrate the full-length SERS-active PCF optofluidics with accumulative Raman signal gain along the entire fiber length. We show SERS measurements of 1x10-7 M (~48 ppb) Rhodamine 6G and 1x10-8 M (~0.8 ppb) sodium thiocyanate in a minute volume of ~10-7-10-8 liter aqueous solution using PCF with immobilized Ag NP over ~20 cm in length. The combination of high detection sensitivity and small sampling volume renders the SERS-active PCF optofluidic platform excellent potential for a multitude of applications ranging from label-free chemical and biological sensing to process monitoring in geometrically confined systems.

[1]  Henry Du,et al.  In situ SERS study of Rhodamine 6G adsorbed on individually immobilized Ag nanoparticles , 2006 .

[2]  S. Sukhishvili,et al.  Layer-by-layer self-assembly of oppositely charged Ag nanoparticles on silica microspheres for trace analysis of aqueous solutions using surface-enhanced Raman scattering. , 2008, Journal of nanoscience and nanotechnology.

[3]  D. Psaltis,et al.  Developing optofluidic technology through the fusion of microfluidics and optics , 2006, Nature.

[4]  Yinian Zhu,et al.  Index-guiding liquid-core photonic crystal fiber for solution measurement using normal and surface-enhanced Raman scattering , 2008 .

[5]  Dimitris C. Lagoudas,et al.  Microstructured Optical Fibers as High-Pressure Microfluidic Reactors , 2006 .

[6]  Alexander Argyros,et al.  Surface enhanced Raman scattering in a hollow core microstructured optical fiber. , 2007, Optics express.

[7]  L. Fu,et al.  All Glass Endless Single Mode Photonic Crystal Fibers , 2008 .

[8]  Henry Du,et al.  Solid-core photonic crystal fiber as a Raman spectroscopy platform with a silica core as an internal reference. , 2006, Optics letters.

[9]  S. Sukhishvili,et al.  Forward-propagating surface-enhanced Raman scattering and intensity distribution in photonic crystal fiber with immobilized Ag nanoparticles. , 2009, Optics letters.

[10]  David Robinson Bassett.  Modern Aspects of Colloidal Dispersions. Results from the DTI Colloid Technology Program. %R. H. Ottewill and A. R. Rennie, Editors. Kluwer Academic Publishers: Dordrecht, 1998; 320 pages. , 2000 .

[11]  Knight,et al.  Single-Mode Photonic Band Gap Guidance of Light in Air. , 1999, Science.

[12]  Yi Zhang,et al.  Liquid core photonic crystal fiber sensor based on surface enhanced Raman scattering , 2007 .

[13]  A. Campion,et al.  Surface-enhanced Raman scattering , 1998 .

[14]  Vittoria Finazzi,et al.  Temperature-insensitive photonic crystal fiber interferometer for absolute strain sensing , 2007 .

[15]  Knight,et al.  Photonic band gap guidance in optical fibers , 1998, Science.

[16]  F Benabid,et al.  Subwatt threshold cw Raman fiber-gas laser based on H2-filled hollow-core photonic crystal fiber. , 2007, Physical review letters.

[17]  J. Dudley,et al.  Supercontinuum generation in photonic crystal fiber , 2006 .

[18]  S. Sukhishvili,et al.  Synthesis of positively charged silver nanoparticles via photoreduction of AgNO3 in branched polyethyleneimine/HEPES solutions. , 2007, Langmuir : the ACS journal of surfaces and colloids.

[19]  R. Dasari,et al.  Single Molecule Detection Using Surface-Enhanced Raman Scattering (SERS) , 1997 .

[20]  T. A. Birks,et al.  Compact, stable and efficient all-fibre gas cells using hollow-core photonic crystal fibres , 2005, Nature.

[21]  D. Meisel,et al.  Adsorption and surface-enhanced Raman of dyes on silver and gold sols , 1982 .

[22]  A. Bjarklev,et al.  Photonic Crystal Fibers: A New Class of Optical Waveguides , 1999 .

[23]  Henry Du,et al.  Structure fits the purpose: photonic crystal fibers for evanescent-field surface-enhanced Raman spectroscopy. , 2010, Optics letters.

[24]  David J. Richardson,et al.  Sensing with microstructured optical fibres , 2001 .

[25]  Steven R. Emory,et al.  Probing Single Molecules and Single Nanoparticles by Surface-Enhanced Raman Scattering , 1997, Science.

[26]  S. Sukhishvili,et al.  Polyelectrolyte adsorption onto an initially-bare solid surface of opposite electrical charge , 1998 .

[27]  H. G. Schulze,et al.  Hollow-core photonic crystal fiber-optic probes for Raman spectroscopy. , 2006, Optics letters.

[28]  S. Sukhishvili,et al.  Towards Full‐Length Accumulative Surface‐Enhanced Raman Scattering‐Active Photonic Crystal Fibers , 2010, Advanced materials.

[29]  M. Natan,et al.  Self-Assembled Metal Colloid Monolayers: An Approach to SERS Substrates , 1995, Science.

[30]  S. Nolte,et al.  High-power air-clad large-mode-area photonic crystal fiber laser , 2003, 2003 Conference on Lasers and Electro-Optics Europe (CLEO/Europe 2003) (IEEE Cat. No.03TH8666).

[31]  Jonathan C. Knight,et al.  Photonic crystal fibres , 2003, Nature.

[32]  J. Baumberg,et al.  Surface‐Enhanced Raman Scattering Using Microstructured Optical Fiber Substrates , 2007 .

[33]  Yinian Zhu,et al.  Liquid-core photonic crystal fiber platform for raman scattering measurements of microliter analyte solutions , 2007, SPIE Optics East.

[34]  Oliver Benson,et al.  Selectively coated photonic crystal fiber for highly sensitive fluorescence detection , 2007 .