Multiple solid-phase system for storage of dry ready-for-use reagents and efficient performance of immunoenzymatic...

A modular system of independent but matching solid phases coated with the reagents for the slide immunoenzymatic assay (SIA) was developed. Antigen, antiserum, second antibody labeled with enzyme, and substrate are immobilized as dry films onto circles surrounded by a hydrophobic material on separate glass slides. The reagents stay on the circles ready for use for at least 1 year. Circles coated with the two reagents involved in each step of the assay are approximated to one another by pairing slides, one on top of the other. Hinged slide frames ensure exact superposition of circles with matching reagents separated by a gap 1 mm thick. This is occupied by a liquid column that forms from a 10 microliters drop of water or buffer pre-deposited onto the circles of the bottom slide. The liquid bridge provides the milieu for interaction of reagents. Pairs of slides are incubated as needed for each step. The enzymatic reaction of the last step is read with a vertical beam spectrophotometer. The same multiple-phase system can be used for immunofluorescence. Reactions occur faster using the system than when reagents are admixed in solution.