Particle-based isolation of proteins and other analytes

A method comprising

• (a) forming a reaction mixture comprising:
• (i) a plurality of proteins, wherein individual proteins of the plurality of proteins each comprise a plurality of first reactive moieties, wherein the plurality of proteins comprises at least 100 different primary protein structures, and
• (ii) a plurality of particles, wherein individual particles of the plurality of particles each comprise a structured nucleic acid particle and a second reactive moiety, wherein the second reactive moiety of the particles is reactive with the first reactive moieties of the proteins, and wherein each of the particles is immobilized on a solid support;
• (b) reacting a first reactive moiety of a protein in the reaction mixture with a second reactive moiety of a particle in the reaction mixture to attach the protein to the particle via a bond formed between the first reactive moiety of the protein and the second reactive moiety of the particle, wherein the reacting yields no more than one protein attached to the particle, and wherein immobilization of the particles inhibits more than one of the particles in the reaction mixture from simultaneously contacting the protein, thereby forming an immobilized particle-protein conjugate on the solid support;
• and
• (c) detaching the immobilized particle-protein conjugate from the solid support in solution-phase, thereby producing a solution-phase particle-protein conjugate.