Multianalyte molecular analysis using application-specific random particle arrays

A method of determining the affinity of several different analyte-binding agent interactions, in a reaction environment where several different such interactions between different analytes and binding agents, take place, and where some of said analytes are capable of binding to more than one said binding agent at different affinities than where binding to other binding agents, comprising:

• providing a plurality of particles comprising at least two different particle populations, wherein different particle populations have different binding agents attached thereto, and wherein the particles are associated with a distinguishable chemical or physical characteristic that identifies the binding agents on said particles;
• contacting the binding agents with an analyte molecule so as to allow the analyte to form an analyte-binding agent complex with one or more binding agents, the formation of said complex resulting in a proportional change in an optical signature associated with the particles whose binding agent is involved in the formation of the complex;
• forming a substantially planar array of the particles on a substrate;
• detecting said change in optical signature associated with said particles from the analyte-binding agent complexes which are formed;
• determining the identity of said binding agents on particles in the array by the distinguishable chemical or physical characteristic associated therewith;
• wherein said proportional change in optical signature for the analyte-binding agent complexes reflects the affinities characterizing said analyte-binding agent interactions associated with each such proportional change;
• compiling a matrix of said affinities;
• and
• compiling a competitive binding interaction descriptor using a combination of the affinities in the matrix and known concentrations of analyte and binding agents participating in the formation of analyte-binding agent complexes.

In a multi-step assay for determining the affinity constant of analyte-binding agent interactions in a reaction environment where a plurality of different such interactions between different analytes and binding agents take place, comprising:

• providing a plurality of particles comprising at least two different particle populations, wherein different particle populations have different binding agents attached thereto, and wherein the particles are associated with a distinguishable chemical or physical characteristic that identities the binding agents on said particles, and wherein the particles are arranged in a substantially planar array on a substrate;
• determining the identity of said binding agents by the distinguishable chemical or physical characteristic associated with the particles;
• contacting the binding agents with a first labeled analyte of interest L in a first binding reaction with a binding agent, where [R0] is the number of binding agents per particle, permitting formation of a first analyte-binding agent complex to yield [LR]1, followed by injection of a second analyte L′ with known affinity constant K′ for the said second binding agent, wherein the affinity constant K is determined from the difference in said optical signature before and after injection of the second analyte to form a second analyte-binding agent complex so as to reduce [LR]1 to [LR]2 given the initial concentration of the labeled analyte, [L0] and the initial concentration of the unlabeled analyte, [L′0] and the number of binding agents per bead, [R0];
• where
• [
• LR
• ]
• 1
• [
• LR
• ]
• 2
• =
• 1
• +
• K
• ⁡
• [
• L
• 0
• ]
• +
• K
• ′
• ⁡
• [
• L
• 0
• ′
• ]
• (
• 1
• +
• K
• ⁡
• [
• L
• 0
• ]
• )
• .