title: A two-magnet strategy for improved mixing and capture from biofluids.
abstract: Magnetic beads are a popular method for concentrating biomolecules from solution and have been more recently used in multistep pre-arrayed microfluidic cartridges. Typical processing strategies rely on a single magnet, resulting in a tight cluster of beads and requiring long incubation times to achieve high capture efficiencies, especially in highly viscous patient samples. This report describes a two-magnet strategy to improve the interaction of the bead surface with the surrounding fluid inside of a pre-arrayed, self-contained assay-in-a-tube. In the two-magnet system, target biomarker capture occurs at a rate three times faster than the single-magnet system. In clinically relevant biomatrices, we find a 2.5-fold improvement in biomarker capture at lower sample viscosities with the two-magnet system. In addition, we observe a 20% increase in the amount of protein captured at high viscosity for the two-magnet configuration relative to the single magnet approach. The two-magnet approach offers a means to achieve higher biomolecule extraction yields and shorter assay times in magnetic capture assays and in self-contained processor designs.
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37235, USA.
authors.forename: Thomas F
authors.identifier: 0000-0002-7077-535X
authors.initials: TF
authors.lastname: Scherr
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37235, USA.
authors.forename: Hayley B
authors.identifier: 0000-0002-4542-5104
authors.initials: HB
authors.lastname: Ryskoski
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37235, USA.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Doyle
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37235, USA.
authors.forename: Frederick R
authors.initials: FR
authors.lastname: Haselton