Abstract: The invention relates to a state-variable feedback control system for monitoring and optimally controlling the operation of a microfluidic aspirate dispense-system. A steady state operating pressure is determined from the fluid, flow and/or operational characteristics of the system. Measurements from one or more pressure sensors are part of the control strategy to derive information for active feedback control and/or to achieve the desired operating pressure. Advantageously, the control system adds to the versatility of the aspirate-dispense system, for example, by permitting rapid dispensing of drops of different size. The control system also desirably facilitates efficient, repeatable and accurate performance and reduces wastage of valuable reagents or fluid.

Abstract: The present invention relates to a ceramic tip and a random access print head for the transfer of microfluidic quantities of fluid. The print head can randomly collect and deposit fluid samples to transfer the samples from a source plate to a target. The print head can also be programmed to create a direct map of the fluid samples from the source plate on the target or to create any desired pattern or print on the target. The tip and print head can be used for a wide variety of applications such as DNA microarraying and compound reformatting. In one preferred embodiment, the tip is used as a capillary or “gravity” pin to draw or collect source fluid and “spot” or deposit the fluid onto the target via physical contact (touch-off). In another preferred embodiment, the tip is used in conjunction with an aspirate-dispense system to actively aspirate source fluid and deposit the fluid via a contact or non-contact approach.

Abstract: A dispensing apparatus and method is provided for accurately and precisely dispensing various desired patterns of reagent onto a substrate or other receptive surface or receptacle. The invention provides high-speed on-the-fly dispensing of various desired reagent patterns as provided by the operator in the form of a graphic bit map file. In one embodiment the dispensing apparatus comprises a dispensing head having an inlet end and an outlet end. The dispensing head is responsive to a first signal to dispense droplets of liquid reagent onto a substrate. The substrate or dispensing head are secured in association with a table or carriage. The table is responsive to a second signal for providing for relative X, X-Y or X-Y-Z motion between the substrate and the dispensing head.