title: Direct-Dispense Polymeric Waveguides Platform for Optical Chemical Sensors.
abstract: We describe an automated robotic technique called direct-dispense to fabricate a polymeric platform that supports optical sensor arrays. Direct-dispense, which is a type of the emerging direct-write microfabrication techniques, uses fugitive organic inks in combination with cross-linkable polymers to create microfluidic channels and other microstructures. Specifically, we describe an application of direct-dispensing to develop optical biochemical sensors by fabricating planar ridge waveguides that support sol-gelderived xerogel-based thin films. The xerogel-based sensor materials act as host media to house luminophore biochemical recognition elements. As a prototype implementation, we demonstrate gaseous oxygen (O2) responsive optical sensors that operate on the basis of monitoring luminescence intensity signals. The optical sensor employs a Light Emitting Diode (LED) excitation source and a standard silicon photodiode as the detector. The sensor operates over the full scale (0%-100%) of O₂ concentrations with a response time of less than 1 second. This work has implications for the development of miniaturized multisensor platforms that can be cost-effectively and reliably mass-produced.
authors.affiliation: Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 2A7. mohamad.hajjhassan@mail.mcgill.ca.
authors.forename: Mohamad
authors.initials: M
authors.lastname: Hajj-Hassan
authors.affiliation: Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6. timothy.gonzalez@mail.mcgill.ca.
authors.forename: Timothy
authors.initials: T
authors.lastname: Gonzalez
authors.affiliation: Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 2A7. ebrahim.ghafarzadeh@mail.mcgill.ca.
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Ghafar-Zadeh
authors.affiliation: Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6. hagop.djeghelian@mail.mcgill.ca.
authors.forename: Hagop
authors.initials: H
authors.lastname: Djeghelian
authors.affiliation: Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 2A7. vamsy.chodavarapu@mcgill.ca.
authors.forename: Vamsy
authors.initials: V
authors.lastname: Chodavarapu
authors.affiliation: Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6. mark.andrews@mcgill.ca.
authors.forename: Mark
authors.initials: M
authors.lastname: Andrews
authors.affiliation: Department of Mechanical Engineering, Ecole Polytechnique de Montreal, Case postale 6079, Succursale Centre-ville, Quebec, Canada H3C 3A7. daniel.therriault@polymtl.ca.
authors.forename: Daniel
authors.initials: D
authors.lastname: Therriault
keywords: Chemical Sensors; Direct-Dispense; Direct-Write; Fluorescence; Optical Sensors; Oxygen Sensors; Polymer Waveguides; Waveguides; Xerogels