A compact device for operatively coupling a solid planar substrate, for example a glass slide, to a microfluidic circuit and performing a reaction or reactions on organic matter bound to the face of the planar substrate. Typical reactions include binding, staining and/or labeling reactions. In use, a sealed reaction chamber is formed, the chamber enclosing the organic matter and at least a part of the solid substrate. Headspace in the sealed chamber between the solid substrate is generally of microfluidic dimensions, and diaphragm pump members are used to inject, exchange and/or mix the fluids in the chamber.