title: A lateral electrophoretic flow diagnostic assay.
abstract: Immunochromatographic assays are a cornerstone tool in disease screening. To complement existing lateral flow assays (based on wicking flow) we introduce a lateral flow format that employs directed electrophoretic transport. The format is termed a "lateral e-flow assay" and is designed to support multiplexed detection using immobilized reaction volumes of capture antigen. To fabricate the lateral e-flow device, we employ mask-based UV photopatterning to selectively immobilize unmodified capture antigen along the microchannel in a barcode-like pattern. The channel-filling polyacrylamide hydrogel incorporates a photoactive moiety (benzophenone) to immobilize capture antigen to the hydrogel without a priori antigen modification. We report a heterogeneous sandwich assay using low-power electrophoresis to drive biospecimen through the capture antigen barcode. Fluorescence barcode readout is collected via a low-resource appropriate imaging system (CellScope). We characterize lateral e-flow assay performance and demonstrate a serum assay for antibodies to the hepatitis C virus (HCV). In a pilot study, the lateral e-flow assay positively identifies HCV+ human sera in 60 min. The lateral e-flow assay provides a flexible format for conducting multiplexed immunoassays relevant to confirmatory diagnosis in near-patient settings.
authors.affiliation: Department of Bioengineering, UC Berkeley, Berkeley, CA 94720 USA. aeh@berkeley.edu.
authors.forename: Robert
authors.initials: R
authors.lastname: Lin
authors.forename: Arunan
authors.initials: A
authors.lastname: Skandarajah
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Gerver
authors.forename: Hector D
authors.initials: HD
authors.lastname: Neira
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Fletcher
authors.forename: Amy E
authors.initials: AE
authors.lastname: Herr
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D000956:Antigens, Viral / Q000737:chemistry / Q000276:immunology; D004586:Electrophoresis / Q000295:instrumentation / Q000379:methods*; D006526:Hepatitis C / Q000175:diagnosis; D006801:Humans; D055767:Immobilized Proteins / Q000276:immunology; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D057054:Molecular Imaging
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D055767:Immobilized Proteins