Patent ID: 8173068

Claim:
An apparatus for adding and removing liquid reagent to and from a sample comprising: a microscope slide supporting the sample; a chamber forming a cavity over said microscope slide, said chamber being releasably sealed to said microscope slide; a fluid port in the wall of said chamber through which fluids can be added or removed, said fluid port having a valve seat, said fluid port further comprising a reagent well capable of retaining an entire aliquot of reagent prior to the reagent passing into the cavity; a normally closed valve comprising a moveable valve element that, in a closed position, presses against the valve seat of the fluid port, said valve capable of opening by movement of the moveable valve element away from the valve seat to admit fluid through the port between the valve seat and the moveable valve element into the chamber; a flexible membrane in said valve, the flexible membrane being an extension of a gasket that surrounds the chamber and seals against the microscope slide; a conduit through which a source of negative or positive air pressure can be communicated; a member associated with the conduit capable of moving the moveable valve element away from the valve seat to open said valve to admit fluid through the port into the chamber; and an actuator capable of causing relative movement between the fluid port and conduit to cause the member to move the moveable valve element away from the valve seat and to engage said conduit and fluid port to each other so that the two are in fluid communication with each other.