title: Multiplexed site-specific electrode functionalization for multitarget biosensors.
abstract: Multitarget biosensors hold great promise to improve point-of-care diagnostics as they enable simultaneous detection of different biomolecular markers. Multiplexed detection of different markers, like genes, proteins, or a combination of both, propels advancement in numerous fields such as genomics, medical diagnosis and therapy monitoring. The functionalization of these biosensors, however, necessitates patterned immobilization of different bioreceptors, which remains challenging and time-consuming. We demonstrate a simple method for the patterned multiplexing of bioreceptors on a multi-electrode chip. By using the lithographically defined electrodes for surface functionalization, additional patterning steps become obsolete. Using the electrodes for self-aligned immobilization provides a spatial resolution that is limited by the electrode patterning process and that cannot be easily obtained by alternative dispensing or coating techniques. Via electrochemical reduction of diazonium salts combined with click chemistry, we achieved site-specific immobilization of two different ssDNA probes side by side on a single chip. This method was experimentally verified by cyclic voltammetry (CV), Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS), and specific target recognition was visualized by fluorescence microscopy. The combination of the electroaddressability of electrografting with the chemoselectivity of click chemistry, offers a versatile platform for highly efficient site-specific functionalization of multitarget biosensors.
authors.affiliation: IMEC, 3001 Leuven, Belgium; KU Leuven Department of Electrical Engineering (ESAT), 3001 Leuven, Belgium. Electronic address: karen.levrie@imec.be.
authors.forename: Karen
authors.initials: K
authors.lastname: Levrie
authors.affiliation: IMEC, 3001 Leuven, Belgium.
authors.forename: Karolien
authors.initials: K
authors.lastname: Jans
authors.affiliation: IMEC, 3001 Leuven, Belgium.
authors.forename: Rita
authors.initials: R
authors.lastname: Vos
authors.affiliation: IMEC, 3001 Leuven, Belgium.
authors.forename: Niyousha
authors.initials: N
authors.lastname: Ardakanian
authors.affiliation: KU Leuven Department of Physics and Astronomy, 3001 Leuven, Belgium; IMEC, 3001 Leuven, Belgium.
authors.forename: Niels
authors.initials: N
authors.lastname: Verellen
authors.affiliation: IMEC, 3001 Leuven, Belgium; KU Leuven Department of Electrical Engineering (ESAT), 3001 Leuven, Belgium.
authors.forename: Chris
authors.initials: C
authors.lastname: Van Hoof
authors.affiliation: IMEC, 3001 Leuven, Belgium; KU Leuven Department of Physics and Astronomy, 3001 Leuven, Belgium.
authors.forename: Liesbet
authors.initials: L
authors.lastname: Lagae
authors.affiliation: IMEC, 3001 Leuven, Belgium.
authors.forename: Tim
authors.initials: T
authors.lastname: Stakenborg
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D015342:DNA Probes / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes
chemical_list: D000814:Aniline Compounds; D015342:DNA Probes; D004277:DNA, Single-Stranded; C023650:aniline
keywords: Click chemistry; Cycloaddition; Diazonium chemistry; Electroaddressable immobilization; Electrografting; Patterning