Highly multiplexed antibody suspension bead arrays for plasma protein profiling.

Alongside the increasing availability of affinity reagents, antibody microarrays have become a powerful tool to screen for target proteins in complex samples. Applying directly labeled samples onto arrays instead of using sandwich assays offers an approach to facilitate a systematic, high-throughput, and flexible exploration of protein profiles in body fluids such as serum or plasma. As an alternative to planar arrays, a system based on color-coded beads for the creation of antibody arrays in suspension has become available to offer a microtiter plate-based option for screening larger number of samples with variable sets of capture reagents. A procedure was established for analyzing biotinylated samples without the necessity to remove excess labeling substance. We have shown that this assay system allows detecting proteins down into lower pico-molar and higher pg/ml levels with dynamic ranges over three orders of magnitude. Presently, this workflow enables the profiling of 384 samples for up to 384 proteins per assay.