title: Paper-based microfluidics with an erodible polymeric bridge giving controlled release and timed flow shutoff.
abstract: Water soluble pullulan films were formatted into paper-based microfluidic devices, serving as a controlled time shutoff valve. The utility of the valve was demonstrated by a one-step, fully automatic implementation of a complex pesticide assay requiring timed, sequential exposure of an immobilized enzyme layer to separate liquid streams. Pullulan film dissolution and the capillary wicking of aqueous solutions through the device were measured and modeled providing valve design criteria. The films dissolve mainly by surface erosion, meaning the film thickness mainly controls the shutoff time. This method can also provide time-dependent sequential release of reagents without compromising the simplicity and low cost of paper-based devices.
authors.affiliation: Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4M1, Canada. filipec@mcmaster.ca.
authors.forename: Sana
authors.initials: S
authors.lastname: Jahanshahi-Anbuhi
authors.forename: Aleah
authors.initials: A
authors.lastname: Henry
authors.forename: Vincent
authors.initials: V
authors.lastname: Leung
authors.forename: Clémence
authors.initials: C
authors.lastname: Sicard
authors.forename: Kevin
authors.initials: K
authors.lastname: Pennings
authors.forename: Robert
authors.initials: R
authors.lastname: Pelton
authors.forename: John D
authors.initials: JD
authors.lastname: Brennan
authors.forename: Carlos D M
authors.initials: CD
authors.lastname: Filipe
mesh_terms: D001331:Automation; D005506:Food Contamination / Q000032:analysis; D005936:Glucans / Q000737:chemistry; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods*; D010209:Paper; D010575:Pesticides / Q000032:analysis; D011108:Polymers / Q000737:chemistry; D014783:Viscosity; D014867:Water / Q000737:chemistry
chemical_list: D005936:Glucans; D010575:Pesticides; D011108:Polymers; D014867:Water; C009109:pullulan