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.

Schwefel in der modernen Materialwissenschaft

“…Die Forschung auf dem Gebiet der Mikrofluidik entwickelt sich auch immer stärker zu einem Schwerpunkt in der Materialwissenschaft . Thiol‐Kupplungen wurden in der Mikrofluidikforschung umfassend genutzt, um so unterschiedliche Materialien wie Funktionspolymere in Form von Kügelchen, Mikroaktuatoren, Fasern mit nicht kreisförmigem Querschnitt, anisotrope Mikropartikel, Sensorkanäle, durch weiche Lithographie erzeugte Mikrostrukturen, Hydrogele und Wellenleiter herzustellen, und auch um mikrofluidische Kanäle selbst zu erzeugen …”

Development of a thiol‐ene based screening platform for enzyme immobilization demonstrated using horseradish peroxidase

“…This excess of functional groups can be used further for surface modification via TEC . Hence, surface hydrophilization, hydrophobization, as well as introduction of biological moieties has been reported . Post preparation modification of the materials has even been shown to be possible by incorporation of glycidyl methacrylate into a photocurable TE material, which resulted in unreacted epoxide groups after curing.…”

Simple Preparation of Thiol–Ene Particles in Glycerol and Surface Functionalization by Thiol–Ene Chemistry (TEC) and Surface Chain Transfer Free Radical Polymerization (SCT‐FRP)

“…The stoichiometric imbalance between functional groups in the OSTE system results in unreacted thiol or ene groups within the polymer structure as well as on surfaces and can therefore directly be used for surface modification via TEC . Thus, hydrophilic and hydrophobic functional groups and biological moieties can easily be introduced, as well as more specific groups, such as maleic anhydride and cysteamine, which have been applied for immobilization of enzymes.…”

“…[11] The stoichiometric imbalance between functional groups in the OSTE system results in unreacted thiol or ene groups within the polymer structure as well as on surfaces and can therefore directly be used for surface modification via TEC. [12][13][14] Thus, hydrophilic and hydrophobic functional groups [15,16] and biological moieties [17] can easily be introduced, as well as more specific groups, such as maleic anhydride [18] and cysteamine, [19] which have been applied for immobilization of enzymes.The high versatility and modularity of TEC has also allowed the preparation of well-defined polymer particles with controlled properties, such as surface functionality, particle size, and thermal and mechanical behavior. Polymer particles are attractive due to their large application spectrum, such as drugdelivery, paints and coatings, chromatography, and catalyst supports.…”