title: Centrifugal microfluidic platform for ultrasensitive detection of botulinum toxin.
abstract: We present an innovative centrifugal microfluidic immunoassay platform (SpinDx) to address the urgent biodefense and public health need for ultrasensitive point-of-care/incident detection of botulinum toxin. The simple, sample-to-answer centrifugal microfluidic immunoassay approach is based on binding of toxins to antibody-laden capture particles followed by sedimentation of the particles through a density-media in a microfluidic disk and quantification by laser-induced fluorescence. A blind, head-to-head comparison study of SpinDx versus the gold-standard mouse bioassay demonstrates 100-fold improvement in sensitivity (limit of detection = 0.09 pg/mL), while achieving total sample-to-answer time of <30 min with 2-μL required volume of the unprocessed sample. We further demonstrate quantification of botulinum toxin in both exogeneous (human blood and serum spiked with toxins) and endogeneous (serum from mice intoxicated via oral, intranasal, and intravenous routes) samples. SpinDx can analyze, without any sample preparation, multiple sample types including whole blood, serum, and food. It is readily expandable to additional analytes as the assay reagents (i.e., the capture beads and detection antibodies) are disconnected from the disk architecture and the reader, facilitating rapid development of new assays. SpinDx can also serve as a general-purpose immunoassay platform applicable to diagnosis of other conditions and diseases.
authors.affiliation: Sandia National Laboratories, 7011 East Avenue, Livermore, California 94551, United States.
authors.forename: Chung-Yan
authors.initials: CY
authors.lastname: Koh
authors.forename: Ulrich Y
authors.initials: UY
authors.lastname: Schaff
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Piccini
authors.forename: Larry H
authors.initials: LH
authors.lastname: Stanker
authors.forename: Luisa W
authors.initials: LW
authors.lastname: Cheng
authors.forename: Easwaran
authors.initials: E
authors.lastname: Ravichandran
authors.forename: Bal-Ram
authors.initials: BR
authors.lastname: Singh
authors.forename: Greg J
authors.initials: GJ
authors.lastname: Sommer
authors.forename: Anup K
authors.initials: AK
authors.lastname: Singh
mesh_terms: D000818:Animals; D001905:Botulinum Toxins / Q000097:blood* / Q000737:chemistry* / Q000276:immunology; D005260:Female; D005504:Food Analysis; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D051379:Mice; D044085:Microfluidics / Q000295:instrumentation*
chemical_list: D001905:Botulinum Toxins