title: Optical chromatography using a photonic crystal fiber with on-chip fluorescence excitation.
abstract: We describe the realization of integrated optical chromatography, in conjunction with on-chip fluorescence excitation, in a monolithically fabricated poly-dimethylsiloxane (PDMS) microfluidic chip. The unique endlessly-single-mode guiding property of the Photonic Crystal Fiber (PCF) facilitates simultaneous on-chip delivery of beams to perform optical sorting in conjunction with fluorescence excitation. We use soft lithography to define the chip and insert the specially capped PCF into it through a predefined fiber channel that is intrinsically aligned with the sorting channel. We compare the performance of the system to a standard ray optics model and use the system to demonstrate both size-driven and refractive index-driven separations of colloids. Finally we demonstrate a new technique of enhanced optofluidic separation of biological particles, by sorting of human kidney embryonic cells (HEK-293), internally tagged with fluorescing microspheres through phagocytocis, from those without microspheres and the separation purity is monitored using fluorescence imaging.
authors.affiliation: SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, Scotland, UK. pca7@st-andrews.ac.uk
authors.forename: P C
authors.initials: PC
authors.lastname: Ashok
authors.forename: R F
authors.initials: RF
authors.lastname: Marchington
authors.forename: P
authors.initials: P
authors.lastname: Mthunzi
authors.forename: T F
authors.initials: TF
authors.lastname: Krauss
authors.forename: K
authors.initials: K
authors.lastname: Dholakia
mesh_terms: D002845:Chromatography / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D017022:Flow Injection Analysis / Q000295:instrumentation*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D017785:Photons; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*