| CPC G01N 33/54326 (2013.01) [G01N 33/54346 (2013.01); G01N 33/551 (2013.01); G01N 33/6848 (2013.01)] | 28 Claims |

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1. A high-throughput method of preparing to identify proteins in a biological sample, the method comprising:
(a) incubating magnetic microparticles with the biological sample to form protein coronas comprising proteins, the magnetic microparticles comprising: (i) silica, (ii) carboxylate functional groups, (iii) negative surface charges from −30 mV to −10 mV in zeta potential, wherein the zeta potential is measurable with a concentration of 0.02 wt % in a solution in 5% pH 7.4 PBS at about 25° C. with an about 1 minute equilibration time on a Zetasizer Nano ZS (Malvern Instruments) in the absence of biological sample, and (iv) a heterogeneous distribution of sizes including from about 1 μm to about 10 μm in diameter, wherein the magnetic microparticles are configured to form protein coronas having at least 200 unique protein groups that can be identified using mass spectrometry;
(b) magnetically isolating the magnetic microparticles, by applying an external magnetic field, from unbound protein in the biological sample to enrich the proteins in the protein coronas;
(c) washing the enriched proteins and the magnetic microparticles after magnetically isolating the magnetic microparticles;
(d) incubating the enriched proteins in the protein coronas by adding a denaturing reagent to the protein coronas and the magnetic microparticles;
(e) digesting the enriched proteins in the protein coronas to generate digested peptides by adding a digestion reagent to the protein coronas and the magnetic microparticles; and
(f) purifying the digested peptides.
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