System and apparatus for sequential processing of analytes
An apparatus and system are provided for simultaneously analyzing a plurality of analytes anchored to microparticles. Microparticles each having a uniform population of a single kind of analyte attached are disposed as a substantially immobilized planar array inside of a flow chamber where steps of an analytical process are carried out by delivering a sequence of processing reagents to the microparticles by a fluidic system under microprocessor control. In response to such process steps, an optical signal is generated at the surface of each microparticle which is characteristic of the interaction between the analyte carried by the microparticle and the delivered processing reagent. The plurality of analytes are simultaneously analyzed by collecting and recording images of the optical signals generated by all the microparticles in the planar array. A key feature of the invention is the correlation of the sequence of optical signals generated by each microparticle in the planar array during the analytical process.
1. A flow chamber, comprising:
an inlet at one end of said flow chamber;
an outlet at another end of said flow chamber; and
a planar cavity in fluid communication with each of said inlet and outlet,
wherein said planar cavity comprises a floor having a plurality of parallel ridges disposed parallel to a longitudinal axis of the flow chamber, and holds a monolayer of microparticles in a substantially immobilized planar array, such that said microparticles form rows between the parallel ridges, and such that processing reagents can access each microparticle during a sequence of processing steps,
wherein the number of microparticles per unit area in the planar array is at least eighty percent of the number of microparticles in a hexagonal array of equal area, or the average distance between centers of adjacent microparticles in the planar array is less than two microparticle diameters;
each of a plurality of the microparticles having an analyte anchored thereto.
2. The flow chamber of claim 1 , wherein the planar cavity further comprises an optically transmissive ceiling substantially parallel to said floor.
3. The flow chamber of claim 1 , wherein each said microparticle has a diameter between about 0.1 and 100μ, which diameter is approximately the same for each microparticle, and said optically transmissive ceiling and said floor are separated by a distance of between about 120 to 150 percent of said diameter.
4. The flow chamber of claim 1 , further comprising a dam adjacent to the outlet, wherein the dam is effective to prevent the passage of the microparticles through said outlet when fluid passes through said flow chamber from said inlet to said outlet.