Frontal and side view of an assembled hybridization chamber. Note, the depression milled into the top portion of the glass plate, which, together with the slide, forms a reservoir of a volume of about 400 µl. Solutions pipetted into the reservoir, enter the narrow hybridization chamber by gravity, and flow partially through the chamber, but are also retained by capillary forces. If a new solution is added to the well, it displaces the previous one. In- and out-flows are uniform and flow rates are low, avoiding tissue shearing by liquid flow. All components of the hybridization chamber are made of heat- and solvent resistant materials and with the exception of the spacers can be reused.