title: Impedimetric Immunosensing in a Porous Volumetric Microfluidic Detector.
abstract: A sensitive and rapid impedemetric immunosensor is demonstrated utilizing porous volumetric microfluidic detection elements and silver enhanced gold nanoparticle probes. The porous detection elements significantly increase capture probe density and decrease diffusion length scales compared to conventional planar sensors to improve target capture efficiency and enhance impedance signal. In this work, a packed bed of silica beads functionalized with antibody probes serves as a porous sensor element within a thermoplastic microchannel, with an interdigitated gold electrode microarray used to measure impedance changes caused by the concentration dependent formation of silver aggregates. The measured impedance change is independent of electrode spacing, enabling a device with low resolution electrodes to achieve a sandwich immunoassay detection limit between 1-10 ng/mL with a 4-log dynamic range, with a total assay time of 75 min.
authors.affiliation: Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Wiederoder
authors.affiliation: Department of Mechanical Engineering, University of Maryland, College Park, Maryland, USA.
authors.forename: Isaac
authors.initials: I
authors.lastname: Misri
authors.affiliation: Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA; Department of Mechanical Engineering, University of Maryland, College Park, Maryland, USA.
authors.forename: Don L
authors.initials: DL
authors.lastname: DeVoe
keywords: conductometric; immunoassay; impedance sensing; nanoparticles; silver enhancement