title: Mild Photochemical Biofunctionalization of Glass Microchannels.
abstract: The ability to locally modify the inside of microfluidic channels with bioactive molecules is of ever-rising relevance. In this article, we show the direct photochemical coupling of a N-hydroxysuccinimide-terminated ω-alkene onto hydrogen-terminated silicon oxide, and its subsequent functionalization with a catalytically active DNAzyme. To achieve this local attachment of a DNAzyme, we prepared hydrogen-phenyl-terminated glass (H-Φ-glass) by the reaction of glass with H-SiPhCl2. The presence of a radical-stabilizing substituent on the Si atom (i.e., phenyl) enabled the covalent modification of bare glass substrates and of the inside of glass microchannels with a functional organic monolayer that allowed direct reaction with an amine-functionalized biomolecule. In this study, we directly attached an NHS-functionalized alkene to the modified glass surface using light with a wavelength of 328 nm, as evidenced by SCA, G-ATR, XPS, SEM, AFM and fluorescence microscopy. Using these NHS-based active esters on the surface, we performed a direct localized attachment of a horseradish peroxidase (HRP)-mimicking hemin/G-quadruplex (hGQ) DNAzyme complex inside a microfluidic channel. This wall-coated hGQ DNAzyme effectively catalyzed the in-flow oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) [ABTS] in the presence of hydrogen peroxide. This proof-of-concept of mild biofunctionalization will allow the facile preparation of modified microchannels for myriad biorelevant applications.
authors.affiliation: Laboratory of Organic Chemistry, Wageningen University and Research , Stippeneng 4, 6708 WE, Wageningen, The Netherlands.|Micronit Microtechnologies B.V., Colosseum 15, 7521 PV, Enschede, The Netherlands.
authors.forename: Rui Rijo
authors.initials: RR
authors.lastname: Carvalho
authors.affiliation: Laboratory of Organic Chemistry, Wageningen University and Research , Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
authors.forename: Sidharam P
authors.initials: SP
authors.lastname: Pujari
authors.affiliation: Laboratory of Organic Chemistry, Wageningen University and Research , Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
authors.forename: Digvijay
authors.initials: D
authors.lastname: Gahtory
authors.affiliation: Micronit Microtechnologies B.V., Colosseum 15, 7521 PV, Enschede, The Netherlands.
authors.forename: Elwin X
authors.initials: EX
authors.lastname: Vrouwe
authors.affiliation: Laboratory of Organic Chemistry, Wageningen University and Research , Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
authors.forename: Bauke
authors.initials: B
authors.lastname: Albada
authors.affiliation: Laboratory of Organic Chemistry, Wageningen University and Research , Stippeneng 4, 6708 WE, Wageningen, The Netherlands.|School of Pharmaceutical Sciences and Technology, Tianjin University , 92 Weijin Road, Tianjin, P.R. China.|Department of Chemical and Materials Engineering, King Abdulaziz University , Jeddah, Saudi Arabia.
authors.forename: Han
authors.identifier: 0000-0001-5773-8506
authors.initials: H
authors.lastname: Zuilhof
mesh_terms: D021881:DNA, Catalytic; D054856:G-Quadruplexes; D006427:Hemin; D006735:Horseradish Peroxidase; D006861:Hydrogen Peroxide; D055668:Photochemical Processes
chemical_list: D021881:DNA, Catalytic; D006427:Hemin; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase