Antibody microarray longevity study: How long‐term storage affects the dynamic range of printed slides

Following development of an antibody microarray we undertook a six month study of a single batch of chips to determine the loss of sensitivity over time. Picogram amounts of capture antibodies are spotted onto epoxy‐silane slides using a Piezorray printer. A single printing, of eleven slides containing 30 anti‐rat antibodies was stored at 4°C in a desiccator until used. A freshly printed slide was analyzed to assure accuracy of print. During the six month test‐period slides were arrayed by first hybridizing with protein standards in separate wells of a pro‐plate system and bound proteins detected using biotin‐conjugated secondary antibodies. Streptavidin conjugated Alexafluor is used to generate the fluorescent signal. A single slide was analyzed with protein standards every two weeks, starting 3 weeks post‐printing and ending at the 6 month time‐point. A single slide was stored at room temperature in a desiccator and tested 3 months post‐printing. We found less than a 2% change in the detection threshold relative to the dynamic range of the standard curves for the slides stored at 4°C. While under the same conditions the slide stored at room temperature exhibited a 15% degradation at 3 months. These findings demonstrate that antibody microarrays can be used for extended periods of time post‐printing, allowing for a single batch of chips to be used for large ongoing studies. Work supported by a grant from Pfizer of Ann Arbor.