Microfabrication and characterization of teflon af-coated liquid core waveguide channels in silicon

Datta, Aniruddha; Eom, In‐Yong; Dhar, Anirban; Kubáň, Pavel; Manor, R.; Ahmad, I.; Gangopadhyay, Shubhra; Dallas, Tim; Holtz, M.; Temkin, H.; Dasgupta, Purnendu Κ.

doi:10.1109/jsen.2003.820343

Cited by 98 publications

(63 citation statements)

References 38 publications

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“…A channel using a coating of Teflon AF and relying on total internal reflection is only limited by the absorption of the water core. It is likely that Teflon AF coated microchannels can be created in microchip cytometers as the methodology to coat microchannels etched in silicon with Teflon AF has previously been developed (18).…”

Section: Discussionmentioning

confidence: 99%

Flow cytometry without alignment of collection optics

Sitton

Srienc²

2009

Cytometry Pt A

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This study describes the performance of a new waveguide flow cell constructed from Teflon AF 1 (TFC) and the potential use of fiber optic splitters to replace collection objectives and dichroic mirrors. The TFC has the unique optical property that the refractive index of the polymer is lower than water and therefore, water filled TFC behaves and functions as a liquid core waveguide. Thus, as cells flow through the TFC and are illuminated by a laser orthogonal to the flow direction, scattered and fluorescent light is directed down the axis of the TFC to a fiber optic. The total signal in the fiber optic is then split into multiple fibers by fiber optic splitters to enable measurement of signal intensities at different wavelengths. Optical filters are placed at the terminus of each fiber before measurement of specific wavelengths by a PMT. The constructed system was used to measure DNA content of CHO and yeast cells. Polystyrene beads were used for alignment and to assess the performance of the system. Polystyrene beads were observed to produce light scattering signals with unique bimodal characteristics dependent on the direction of flow relative to the collecting fiber optic. (1) and have since been refined into highly developed, sophisticated instruments. Over this time, the basic principles have not been changed significantly. In traditional flow cytometry, the illuminating laser beam and the light collection optics are placed in the same plane perpendicular to the flow stream. In most current instrument configurations microscope objectives gather scattered or fluorescent light. In place of microscope objectives, optical waveguides butted against the flow cell wall have been proposed and shown to collect light similar to microscope objectives (2). The collected light is then passed through a series of dichroic mirrors and bandpass filters to measure light from fluorophores correlated with a specific aspect of cell physiology. For high accuracy and precision, this traditional arrangement requires a precise alignment between the illumination optics, the flow stream, the collection optics, and the dichroic mirrors and filters used. Properly aligning these elements is a sensitive task that requires considerable skill and experience.Current research to expand this technology has taken two directions: (i) development of higher-end cytometers with increasing signal strength, numbers of illuminating lasers, and fluorescence parameters analyzed (3-5) and (ii) development of instruments that are smaller, less expensive, and more accessible (Guava Technologies, Accuri) (6-8). This report describes an alternate configuration that has the potential to make cytometers less expensive, more accessible, and more robust.The described instrument configuration uses a Teflon AF capillary as the flow cell (TFC). The TFC has the unique optical property that the refractive index of the polymer (n 5 1.290) is lower than water (n 5 1.333) (9). Thus, a water filled TFC

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Section: Discussionmentioning

confidence: 99%

Flow cytometry without alignment of collection optics

Sitton

Srienc²

2009

Cytometry Pt A

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“…Liquid core fibers consisting of either Teflon AF tubes or glass capillaries coated internally with Teflon AF have been applied in sensing since 1990s [6]. More recently the integration silicon, glass or PDMS substrates of these waveguides has been also demonstrated [7][8]. However, the use of Teflon AF is not easy and poses strong limitations.…”

Section: Optofluidic Waveguidesmentioning

confidence: 99%

Optofluidics: a new tool for sensing

Testa¹,

Persichetti²,

Zeni

et al. 2013

SPIE Proceedings

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Over the last years optofluidics has emerged as a very promising field. The integration at microscopic level between optics and microfluidics provides a number of unique characteristics that cannot be obtained with solid materials only. This paper briefly reviews the state of the art on optofluidics for sensing applications. We first describe the different approaches in order to realized optofluidic waveguides. These waveguides allow an increased interaction efficiency between the light and the liquid substance that can be very useful in sensing applications (fluorescence, absorption spectroscopy, etc.). We then illustrate high sensitive optofluidic devices such as Mach-Zehnder interferometers, FabryPérot cavities and ring resonators. Examples of applications of optofluidic sensors for chemical and biological analysis are given.

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“…Teflon ® AF coating to create integrated TIR-based waveguides on silicon (Datta et al 2003) -see Fig. 4b.…”

Section: Teflon Coated Microchannels In Silicon-wafer Bonding Was Commentioning

confidence: 99%

Optofluidic waveguides: II. Fabrication and structures

Hawkins

Schmidt

2007

Microfluid Nanofluid

110

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We review fabrication methods and common structures for optofluidic waveguides, defined as structures capable of optical confinement and transmission through fluid filled cores. Cited structures include those based on total internal reflection, metallic coatings, and interference based confinement. Configurations include optical fibers and waveguides fabricated on flat substrates (integrated waveguides). Some examples of optofluidic waveguides that are included in this review are Photonic Crystal Fibers (PCFs) and two-dimensional photonic crystal arrays, Bragg fibers and waveguides, and Anti Resonant Reflecting Optical Waveguides (ARROWs). An emphasis is placed on integrated ARROWs fabricated using a thin-film deposition process, which illustrates how optofluidic waveguides can be combined with other microfluidic elements in the creation of lab-on-a-chip devices.

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Microfabrication and characterization of teflon af-coated liquid core waveguide channels in silicon

Cited by 98 publications

References 38 publications

Flow cytometry without alignment of collection optics

Flow cytometry without alignment of collection optics

Optofluidics: a new tool for sensing

Optofluidic waveguides: II. Fabrication and structures

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