title: Automated microfluidic processing platform for multiplexed magnetic bead immunoassays.
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.
authors.affiliation: BioMEMS Laboratory, Department of Biomedical Engineering, Rutgers, The State University of New Jersey, 599 Taylor Road, Piscataway, NJ 08854, USA.
authors.forename: Lawrence A
authors.initials: LA
authors.lastname: Sasso
authors.affiliation: BioMEMS Laboratory, Department of Biomedical Engineering, Rutgers, The State University of New Jersey, 599 Taylor Road, Piscataway, NJ 08854, USA.
authors.forename: Ian H
authors.initials: IH
authors.lastname: Johnston
authors.affiliation: BioMEMS Laboratory, Department of Biomedical Engineering, Rutgers, The State University of New Jersey, 599 Taylor Road, Piscataway, NJ 08854, USA.
authors.forename: Mingde
authors.initials: M
authors.lastname: Zheng
authors.affiliation: BioMEMS Laboratory, Department of Biomedical Engineering, Rutgers, The State University of New Jersey, 599 Taylor Road, Piscataway, NJ 08854, USA.
authors.forename: Rohit K
authors.initials: RK
authors.lastname: Gupte
authors.affiliation: Penn State Hershey Pediatric Cardiovascular Research Center, Department of Pediatrics, Surgery, and Bioengineering, Penn State Milton S. Hershey Medical Center, Penn State College of Medicine, Penn State Children's Hospital, Hershey, PA, 17033-0850, USA.
authors.forename: Akif
authors.initials: A
authors.lastname: Ündar
authors.affiliation: Department of Biomedical Engineering, Rutgers, The State University of New Jersey, Room 311, 599 Taylor Road, Piscataway, NJ 08854, USA.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Zahn
keywords: Biosensor; Fluorocytometry; Immunoassay; Magnetic; Microfluidic