title: Pluronic additives: a solution to sticky problems in digital microfluidics.
abstract: Digital microfluidics (DMF) is a promising technique for carrying out miniaturized, automated biochemical assays in which discrete droplets of reagents are actuated on the surface of an array of electrodes. A limitation for DMF is nonspecific protein adsorption to device surfaces, which interferes with assay fidelity and can cause droplets to become unmovable. Here, we report the results of a quantitative analysis of protein adsorption on DMF devices by means of confocal microscopy and secondary ion mass spectrometry. This study led us to a simple and effective method for limiting the extent of protein adsorption: the use of low concentrations of Pluronic F127 as a solution additive. This strategy has a transformative effect on digital microfluidics, facilitating the actuation of droplets containing greater than 1000-fold higher protein concentrations than is possible without the additive. To illustrate the benefits of this new method, we implemented a DMF-driven protein digest assay using large concentrations (1 mg/mL) of protein-substrate. The use of Pluronic additives solves a sticky problem in DMF, which greatly expands the range of applications that are compatible with this promising technology.
authors.affiliation: Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Vivienne N
authors.initials: VN
authors.lastname: Luk
authors.forename: Gary Ch
authors.initials: GCh
authors.lastname: Mo
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Wheeler
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D004566:Electrodes; D004867:Equipment Design; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D046210:Microfluidic Analytical Techniques; D044085:Microfluidics; D018613:Microscopy, Confocal; D020442:Poloxamer / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry; D012709:Serum Albumin / Q000737:chemistry; D012997:Solvents; D013499:Surface Properties
chemical_list: D011506:Proteins; D012709:Serum Albumin; D012997:Solvents; D020442:Poloxamer