Design of atto-vial based recombinant antibody arrays combined with a planar wave-guide detection system

Antibody microarray is a rapidly emerging, powerful approach with great promise within high-throughput proteomics. However, before a truly proteome-wide analysis can be performed, the antibody array format needs to be miniaturized even further in order to enable ultradense arrays to be fabricated. To this end, we have designed and generated proof-of-concept for the first generation of an atto-vial based recombinant antibody array platform. Briefly, we have designed a novel nanostructured substrate using electron beam lithography. Vials, ranging in volume/size from 6 (200 nm in diameter) to 4000 aL (5 microm in diameter), were fabricated. Human recombinant single-chain Fv antibody fragments, microarray adopted by design, were used as probes. The set-up was interfaced with planar wave-guide technology for evanescant field fluorescence detection. The results showed that protein analytes could be specifically detected in the subzeptomole range for pure systems, using vials down to 57 aL. Further, low-abundant (pg/mL) protein analytes could be detected in directly labeled complex proteomes, such as human whole serum, using 157 aL-vials. Taken together, these results outline the potential of the atto-vial array set-up for miniaturized affinity proteomics-based approaches.