Toward immobilized antibody microarray optimization: print buffer and storage condition comparisons on performance

Performance issues in protein arrays differ substantially from DNA microarrays because of the different intrinsic construction and stability of proteins versus DNA, and the impact on biological recognition phenomena required for assay from a surface-immobilized state. Maintenance of the capture bioactivity and performance of antibodies on microarray substrates for relatively long periods (under storage or shipping) requires carefully designed and optimized print buffer and storage conditions. We have focused on selection of several additives added to antibody print buffers with different concentrations, and storage of printed antibody slides under different temperatures from 1 day to 4 weeks. Activities of these slides were compared in capture assay formats in order to compare the effects of print buffer and storage conditions of antibody microarrays. Commercial polymer-coated Optarray slides exhibited better performance over Codelink slides in terms of activity of anti-human TNF alpha and IL-1 beta. IL-1 beta antibodies immobilized on both commercial surfaces showed much higher activity than TNF alpha antibodies, regardless of source or vendor. Addition of 1% (v/v) PEO to the print buffer increased the printed analyte capture activity of IL-1 beta on Optarray slides compared to standard print buffer without any additives. This helps to maintain antibody immobilized analyte capture activity for 4 weeks when stored at -70 degrees C.