Development of novel lab-on-a-chip platform for high-throughput radioimmunoassay.

Radioimmunoassay (RIA) is an extremely specific and a highly sensitive type of immunoassay, but the long incubation time and generation of radioactive wastes limit the use of RIA. To complement these disadvantages of RIA, we suggest an advanced type of RIA based on a lab-on-a-chip (LOC) platform: μ-RIA. We designed a microfluidic chip for RIA and optimized the procedures of μ-RIA analysis, including surface modification, immunoreaction time, and washing. Based on the optimized conditions, we conducted a radioimmunoassay on the μ-RIA platform using a commercial RIA kit. With the μ-RIA, 5 min are adequate for analysis. The amount of reagent consumption is significantly reduced compared with conventional RIA. The standard curve with R = 0.9951 shows that we can quantitatively evaluate the amount of antigen present in unknown samples. We show the applicability of μ-RIA for the analysis of biomolecules and the potential of μ-RIA to be a novel platform for high-throughput analysis.