Automated microfluidic processing platform for multiplexed magnetic bead immunoassays

Lawrence A. Sasso, Ian H. Johnston, Mingde Zheng, Rohit K. Gupte, Akif Ündar, Jeffrey D. Zahn

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

A microfluidic platform is presented which fully automates all incubation steps of a three-stage, multiplexed magnetic bead immunoassay, such as the Luminex® xMAP technology. Magnetic actuation is used to transfer the microbeads between co-infused adjacent laminar flow streams to transport the beads into and out of incubation and wash solutions, with extended incubation channels to allow sufficient bead incubation times (1-30 min, commonly 5 min per stage) to enable high-sensitivity. The serial incubation steps of the immunoassay are completed in succession within the device with no operator interaction, and the continuous flow operation with magnetic bead transfer defines the incubation sequencing requiring no external fluidic controls beyond syringe pump infusion. The binding kinetics of the assay is empirically characterized to determine the required incubation times for specific assay sensitivities in the range 1 pg/ml to 100 ng/ml. By using a Luminex ® xMAP duplex assay, concurrent detection of IL-6 and TNF-α was demonstrated on-chip with a detection range 10 pg/ml to 1 ng/ml. This technology enables rapid automation of magnetic microbead assays, and has the potential to perform continuous concentration monitoring.

Original languageEnglish (US)
Pages (from-to)603-612
Number of pages10
JournalMicrofluidics and Nanofluidics
Volume13
Issue number4
DOIs
StatePublished - Oct 2012

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Materials Chemistry

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