Apparatuses and associated methods for manipulating an assembly of glass slides employed in cellular assay processes are provided. Each apparatus can accommodate at least one removable rack of slides to undergo electrophoresis in a comet assay. The slides can remain in the same apparatus while being subjected to a sequence of fluid staining and washing with temperature control, advantageously shortening the amount of time required for processing the slides by keeping them in the same work station for the entire duration of the assay.