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.
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机译：提出了一种微流体平台，该平台可完全自动化三阶段，多重磁珠免疫测定（例如Luminex ® xMAP技术）的所有孵育步骤。磁驱动用于在共注入的相邻层流之间转移微珠，以将微珠运入培养液和洗涤液中，并通过扩展的培养通道提供足够的微珠培养时间（1–30分钟，通常每个阶段5分钟） ）以实现高灵敏度。免疫测定的连续孵育步骤是在设备内连续完成的，无需操作员干预，并且具有磁珠转移功能的连续流操作定义了孵育顺序，除了注射针筒注入外，不需要任何外部流体控制。根据经验对测定的结合动力学进行表征，以确定特定测定灵敏度在1 pg / ml至100 ng / ml范围内所需的孵育时间。通过使用Luminex的xMAP双工分析，可以在芯片上同时检测IL-6和TNF-α，检测范围为10 pg / ml至1 ng / ml。该技术可实现磁性微珠测定的快速自动化，并具有执行连续浓度监测的潜力。
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