Analysis of inflammatory biomarkers by Arrayed Imaging Reflectometry.

Levels of serum cytokines are important markers for a broad range of human health conditions, ranging from infectious disease and cancer, to pollutant exposure and stress. In the interest of developing new rapid label-free methods for profiling serum cytokines, we have examined the utility of Arrayed Imaging Reflectometry (AIR) microarrays for this application. We find that AIR is readily able to profile 14 cytokines and other inflammatory biomarker proteins in a background of buffered bovine serum albumin or 1% bovine serum with performance metrics comparable to singleplex ELISA, but in a multiplex, chip-based, reagentless format. Further experiments with interferon-gamma (IFN-γ) demonstrated that the concentration of bovine serum could be increased to at least 20% without changing the overall analytical profile or limit of detection (<10 pg/mL).