COST-EFFECTIVE MULTIPLEXED IMMUNOASSAYS USING SILVER PRECIPITATION AND A DESKTOP SCANNER

We introduce a multiplexed sandwich immunoassay using silver precipitation to produce a visible read-out that can be quantified using a common desktop scanner, thus eliminating the need for a fluorescent scanner and reducing the overall cost of a multiplexed test. We benchmarked our technique against a fluorescence immunosorbent microarray and found that all LOD values obtained with a desktop scanner come close to those obtained with a fluorescence scanner. We further performed parallel quantification of four proteins (EGF, IL1b, G-CSF, and TNF-RII) spiked in diluted serum and the values extracted using the two methods were found to be in good agreement (coefficient of determination R 2 >0.9). This assay costs only a fraction of a fluorescence assay, thereby it may benefit the development of low-cost multiplexed immunoassays.