title: A digital microfluidic device with integrated nanostructured microelectrodes for electrochemical immunoassays.
abstract: Nanostructured microelectrodes (NMEs) are three-dimensional electrodes that have superb sensitivity for electroanalysis. Here we report the integration of NMEs with the versatile fluid-handling system digital microfluidics (DMF), for eventual application to distributed diagnostics outside of the laboratory. In the new methods reported here, indium tin oxide DMF top plates were modified to include Au NMEs as well as counter and pseudoreference electrodes. The new system was observed to outperform planar sensing electrodes of the type that are typically integrated with DMF. A rubella virus (RV) IgG immunoassay was developed to evaluate the diagnostic potential for the new system, relying on magnetic microparticles coated with RV particles and analysis by differential pulse voltammetry. The limit of detection of the assay (0.07 IU mL(-1)) was >100× below the World Health Organization defined cut-off for rubella immunity. The sensitivity of the integrated device and its small size suggest future utility for distributed diagnostics.
authors.affiliation: Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada. shana.kelley@utoronto.ca aaron.wheeler@utoronto.ca.
authors.forename: Darius G
authors.initials: DG
authors.lastname: Rackus
authors.forename: Michael D M
authors.initials: MD
authors.lastname: Dryden
authors.forename: Julian
authors.initials: J
authors.lastname: Lamanna
authors.forename: Alexandre
authors.initials: A
authors.lastname: Zaragoza
authors.forename: Brian
authors.initials: B
authors.lastname: Lam
authors.forename: Shana O
authors.initials: SO
authors.lastname: Kelley
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Wheeler
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods; D006041:Goats; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods; D007074:Immunoglobulin G / Q000737:chemistry*; D056656:Lab-On-A-Chip Devices; D008839:Microelectrodes; D049329:Nanostructures / Q000737:chemistry*; D012412:Rubella virus / Q000737:chemistry*
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G