Microarray devices fabricated using microfluidic
reagent distribution techniques are provided. As described herein, the invention encompasses microfluidic
microarray assemblies (MMA) and subassemblies and methods for their manufacture and use. In one embodiment first and second channel plates are provided which may be sealed to a test
chip in consecutive steps. Each channel plate includes microfluidic channels configured in a predetermined
reagent distribution pattern. For example, the first channel plate may have a radial (linear)
reagent distribution pattern and the second channel plate may have a spiral (curved) reagent
distribution pattern, or vice versa. In one embodiment the first channel plate is connected to the test
chip and at least one first reagent is distributed on the test
chip in a first predetermined reagent pattern. The first reagent is then immobilized on the test chip. Next, the first channel plate is removed, the second channel plate is connected to the test chip and at least one second reagent is distributed on the test chip in a second predetermined reagent pattern. The first and second reagent patterns intersect to define a plurality of
microarray test positions on the test chip. In one embodiment, the first reagent may comprise a plurality of separate probes each distributed to selected test position(s) of the
microarray and the second reagent may comprise a plurality of test samples each distributed to selected test position(s) of the microarray. Positive or negative reactions between the probes (or other first reagent) and test samples (or other second reagent) may then be detected at the microarray test positions. For example, hybridization between selected
nucleic acid probes and selected
nucleic acid samples may be detected at particular test positions. The invention thus provides an efficient means to fabricate
high density multi-probe, multi-sample microarrays. Preferably the test chips and channel plates are circular and
centrifugal force is used to achieve fluid flow through the microfluidic channels, such as by rotating the MMA in a disc spinner.