An automated microfluidic-based immunoassay cartridge for allergen screening and other multiplexed assays

A microfluidic cartridge and system for multiplexed immunoassays is described. The passive microfluidic cartridge was composed of three layers of injection molded plastic sealed together using a thermal staking technique. Using this platform technology, a specific immunoglobulin E (IgE) panel assay was constructed. Allergen extract targets, positive and negative controls, and IgE calibration standards were immobilized within the cartridge as a microarray. A computer-controlled solenoid array provided the necessary actuation force for pumping reagents within the cartridge to perform an automated, chemiluminescent indirect immunoassay. A 20-target allergen extract panel was demonstrated on the device with a total analysis time of 27 min. Allergen screening results showed 84% agreement for 3 house dust mites (N=300) compared with a commercial test and 80% agreement overall (N=978). Average coefficients of variation (N=80) were measured as 20.5% for low/medium levels and 20.4% for medium/high levels. The average limit of detection (N=160) was measured at 0.535 AU, and cutoff levels of 1.0 AU were estimated at less than 1 IU/ml (2.4 ng/ml). Such a system has potential applications in decentralized allergen screening as well as in other near-patient diagnostic immunoassays where multiplexed analysis, ease of use, and short analysis time are critical.