Diffusion immunoassay for protein analytes

The diffusion immunoassay, a new microfluidic assay technique, may be an enabling technology for the development of point-of-care immunoassay systems. We have previously described this novel, clinically significant, quantitative, immunoassay technique based on the differences in the diffusivity of an analyte and the complex of that analyte and a specific antibody; it assayed phenytoin in whole blood. In this report, DIAs for two model protein analytes - horseradish peroxidase and IgG - are described. The key parameters in the DIA and how they interact to change the performance of the DIA when proteins are the analytes are discussed. Simulations for several protein DIAs and preliminary results that suggest that the simulations are accurate are presented. Several methods for increasing, the signal are discussed and simulated