A compact optofluidic cytometer with integrated liquid-core/PDMS-cladding waveguides.

We developed a simple method to construct liquid-core/PDMS-cladding optical waveguides through pressurized filling of dead-ended micro-channels with optical fluids. The waveguides are in the same layer as microfluidic channels which greatly simplifies device fabrication. With proper contrast between the refractive index of the core and cladding, the transmission loss of the waveguides is less than 5 dB cm(-1). We also developed a method to create flat and optically clear surfaces on the sides of PDMS devices in order to couple light between free-space and the waveguides embedded inside the chip. With these newly developed techniques, we make a compact flow cytometer and demonstrate the fluorescence counting of single cells at a rate of up to ~50 cell s(-1) and total sample requirement of a few microlitres. This method of making liquid-core optical waveguides and flat surfaces has great potential to be integrated into many PDMS-based microsystems.

[1]  Harry L. T. Lee,et al.  Polymer waveguide backplanes for optical sensor interfaces in microfluidics. , 2007, Lab on a chip.

[2]  Anders Kristensen,et al.  UV patterned nanoporous solid-liquid core waveguides. , 2010, Optics express.

[3]  Nickolaj J. Petersen,et al.  Monolithic integration of optical waveguides for absorbance detection in microfabricated electrophoresis devices , 2001, Electrophoresis.

[4]  S. Takayama,et al.  Microfluidics for flow cytometric analysis of cells and particles , 2005, Physiological measurement.

[5]  Amadeu Griol,et al.  Label-free optical biosensing with slot-waveguides. , 2008, Optics letters.

[6]  Christelle Monat,et al.  Integrated optofluidics: A new river of light , 2007 .

[7]  J. Jensen,et al.  Photonic crystal fiber long-period gratings for biochemical sensing. , 2006, Optics express.

[8]  A. Hawkins,et al.  The photonic integration of non-solid media using optofluidics , 2011 .

[9]  Xudong Fan,et al.  Optofluidic Microsystems for Chemical and Biological Analysis. , 2011, Nature photonics.

[10]  S. Quake,et al.  Dissecting biological “dark matter” with single-cell genetic analysis of rare and uncultivated TM7 microbes from the human mouth , 2007, Proceedings of the National Academy of Sciences.

[11]  Z. Fang,et al.  A miniaturized liquid core waveguide-capillary electrophoresis system with flow injection sample introduction and fluorometric detection using light-emitting diodes. , 2001, Analytical chemistry.

[12]  Yeshaiahu Fainman,et al.  On-chip microfluidic tuning of an optical microring resonator , 2006 .

[13]  Gwo-Bin Lee,et al.  Micro flow cytometers with buried SU-8/SOG optical waveguides , 2003 .

[14]  D. Tsai,et al.  Optofluidic waveguide as a transformation optics device for lightwave bending and manipulation , 2012, Nature Communications.

[15]  Guoan Zheng,et al.  The ePetri dish, an on-chip cell imaging platform based on subpixel perspective sweeping microscopy (SPSM) , 2011, Proceedings of the National Academy of Sciences.

[16]  Qi Jie Wang,et al.  A tunable 3D optofluidic waveguide dye laser via two centrifugal Dean flow streams. , 2011, Lab on a chip.

[17]  Luke P. Lee,et al.  Tunable liquid-filled microlens array integrated with microfluidic network. , 2003, Optics express.

[18]  Nam-Trung Nguyen,et al.  Disposable flow cytometer with high efficiency in particle counting and sizing using an optofluidic lens. , 2011, Optics letters.

[19]  Y. Lo,et al.  Optofluidic Waveguides in Teflon AF-Coated PDMS Microfluidic Channels , 2009, IEEE Photonics Technology Letters.

[20]  Stephen R Quake,et al.  Velocity‐independent microfluidic flow cytometry , 2002, Electrophoresis.

[21]  George M. Whitesides,et al.  Optical waveguiding using thermal gradients across homogeneous liquids in microfluidic channels , 2006 .

[22]  Matthew C. Mowlem,et al.  Design, simulation and characterisation of integrated optics for a microfabricated flow cytometer , 2010 .

[23]  A D Stroock,et al.  An integrated fluorescence detection system in poly(dimethylsiloxane) for microfluidic applications. , 2001, Analytical chemistry.

[24]  Demetri Psaltis,et al.  Pneumatically tunable optofluidic dye laser , 2010 .

[25]  E. Chow,et al.  Ultra compact biochemical sensor built with two dimensional photonic crystal microcavity , 2004, InternationalQuantum Electronics Conference, 2004. (IQEC)..

[26]  S. Kuiper,et al.  Variable-focus liquid lens for miniature cameras , 2004 .

[27]  P. Sarro,et al.  Integrated optofluidic Mach–Zehnder interferometer based on liquid core waveguides , 2008 .

[28]  G. Whitesides,et al.  Dynamic control of liquid-core/liquid-cladding optical waveguides , 2004, (CLEO). Conference on Lasers and Electro-Optics, 2005..

[29]  Yu-Hwa Lo,et al.  Human mammalian cell sorting using a highly integrated micro-fabricated fluorescence-activated cell sorter (microFACS). , 2010, Lab on a chip.

[30]  Peng Fei,et al.  Discretely tunable optofluidic compound microlenses. , 2011, Lab on a chip.

[31]  Anders Kristensen,et al.  PMMA to SU-8 bonding for polymer based lab-on-a-chip systems with integrated optics , 2004 .

[32]  Tony Jun Huang,et al.  Hydrodynamically tunable optofluidic cylindrical microlens. , 2007, Lab on a chip.

[33]  P. Schwille,et al.  Dual-color fluorescence cross-correlation spectroscopy for multicomponent diffusional analysis in solution. , 1997, Biophysical journal.

[34]  Yu-Hwa Lo,et al.  Two-parameter angular light scatter collection for microfluidic flow cytometry by unique waveguide structures , 2010, Biomedical optics express.

[35]  L C Kimerling,et al.  Fabrication of ultralow-loss Si/SiO(2) waveguides by roughness reduction. , 2001, Optics letters.

[36]  Xudong Fan,et al.  Liquid-core optical ring-resonator sensors. , 2006, Optics letters.

[37]  Y. Lo,et al.  Lab-on-a-chip flow cytometer employing color-space-time coding. , 2010, Applied physics letters.

[38]  J Fedeli,et al.  Optical manipulation of microparticles and cells on silicon nitride waveguides. , 2005, Optics express.

[39]  Lisa R. Hilliard,et al.  Multi-wavelength microflow cytometer using groove-generated sheath flow. , 2009, Lab on a chip.

[40]  Demetri Psaltis,et al.  Lensless high-resolution on-chip optofluidic microscopes for Caenorhabditis elegans and cell imaging , 2008, Proceedings of the National Academy of Sciences.

[41]  Jeffrey S Erickson,et al.  The good, the bad, and the tiny: a review of microflow cytometry , 2008, Analytical and bioanalytical chemistry.

[42]  Paul Hickson,et al.  Deposition of metal films on an ionic liquid as a basis for a lunar telescope , 2007, Nature.

[43]  George M. Whitesides,et al.  Fabrication of Liquid‐Core Waveguides by Soft Lithography , 1999 .

[44]  P. H. Yap,et al.  Refractive index measurement of single living cells using on-chip Fabry-Pérot cavity , 2006 .

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

[46]  Yu-Hwa Lo,et al.  Review Article: Recent advancements in optofluidic flow cytometer. , 2010, Biomicrofluidics.

[47]  S. Quake,et al.  Monolithic microfabricated valves and pumps by multilayer soft lithography. , 2000, Science.

[48]  Demetri Psaltis,et al.  Optofluidic membrane interferometer: An imaging method for measuring microfluidic pressure and flow rate simultaneously on a chip. , 2011, Biomicrofluidics.

[49]  C. Bliss,et al.  Rapid fabrication of a microfluidic device with integrated optical waveguides for DNA fragment analysis. , 2007, Lab on a chip.

[50]  B. Gale,et al.  A monolithic PDMS waveguide system fabricated using soft-lithography techniques , 2005, Journal of Lightwave Technology.