title: Surface functionalized thiol-ene waveguides for fluorescence biosensing in microfluidic devices.
abstract: Thiol-ene polymers possess physical, optical, and chemical characteristics that make them ideal substrates for the fabrication of optofluidic devices. In this work, thiol-ene polymers are used to simultaneously create microfluidic channels and optical waveguides in one simple moulding step. The reactive functional groups present at the surface of the thiol-ene polymer are subsequently used for the rapid, one step, site-specific functionalization of the waveguide with biological recognition molecules. It was found that while the bulk properties and chemical surface properties of thiol-ene materials vary considerably with variations in stoichiometric composition, their optical properties remain mostly unchanged with an average refractive index value of 1.566 ± 0.008 for thiol-ene substrates encompassing a range from 150% excess ene to 90% excess thiol. Microfluidic chips featuring thiol-ene waveguides were fabricated from 40% excess thiol thiol-ene to ensure the presence of thiol functional groups at the surface of the waveguide. Biotin alkyne was photografted at specific locations using a photomask, directly at the interface between the microfluidic channel and the thiol-ene waveguide prior to conjugation with fluorescently labeled streptavidin. Fluorescence excitation was achieved by launching light through the thiol-ene waveguide, revealing bright fluorescent patterns along the channel/waveguide interface.
authors: Department of Micro- and Nanotechnology, Technical University of Denmark, Kongens Lyngby, Denmark.
authors: Nikolaj A
authors: NA
authors: Feidenhans'l
authors: Josiane P
authors: JP
authors: Lafleur
authors: Thomas G
authors: TG
authors: Jensen
authors: Jörg P
authors: JP
authors: Kutter
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D011108:Polymers / Q000737:chemistry*; D012031:Refractometry; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D011108:Polymers; D013438:Sulfhydryl Compounds
keywords: Biosensing; Fluorescence; Microfluidics; Surface functionalization; Thiol-ene