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 method for tracking and analysis of multiple analytes through a series of processing steps, wherein said analytes are anchored to a plurality of microparticles, the method comprising:
providing a population of microparticles, held in a planar array within a flow chamber, of which said plurality of microparticles have said multiple analytes anchored thereto;
for each of a series of processing steps:
(i) delivering processing reagents having optically detectable labels to the flow chamber, such that said multiple analytes are contacted with the processing reagents,
(ii) exposing said plurality of microparticles to radiation, thereby producing optical signals from products of interaction between said optically labeled reagents and said analytes on the microparticles, and
(iii) detecting and recording said optical signals from each microparticle of the plurality,
to produce a sequence of optical signals for each microparticle of the plurality;
tracking the positions of said plurality of microparticles within the array during said processing steps, by collecting images derived from scattered or focused light from said microparticles, thereby determining the approximate center of each microparticle; and
correlating said sequences of optical signals with said positions.
2. The method of claim 1 , wherein said detecting and recording comprises focusing said optical signals onto a solid state imaging device which is capable of generating a digital image of the microparticle array with sufficient resolution for individual microparticles to be distinguished.
3. The method of claim 1 , wherein said collected images comprise focused back light from back lighted microparticles or the scatter centers of top-lighted microparticles.
4. The method of claim 1 , wherein said analytes are oligonucleotides or nucleic acid molecules.