Methods of measuring hydrophobicity of chromatographic resins

A method of selecting a chromatographic resin condition for purifying a protein of interest from a mixture, wherein the protein of interest has a low or no aggregation formation during chromatography, comprising:

• (a) mixing a fluorophore with a gold nanoparticle (GNP) to form a fluorophore-conjugated gold nanoparticle;
• (b) contacting the fluorophore-conjugated gold nanoparticle with a chromatographic resin in a solution under different conditions;
• (c) removing a supernatant and washing the chromatographic resin with a washing buffer;
• (d) quantifying a level of fluorescence intensity of the chromatographic resin from different conditions in (b);
• (e) measuring a level of hydrophobicity of the chromatographic resin under different conditions, wherein the level of the fluorescence intensity from (d) is indicative of the level of hydrophobicity of a chromatographic resin;
• and
• (f) selecting the chromatographic resin condition based on the level of hydrophobicity of the chromatographic resin which leads to the low or no aggregation formation during chromatography purification of the protein of interest.

A method of selecting a chromatographic resin from a plurality of chromatographic resins for purifying a protein of interest from a mixture, wherein the protein of interest has a low or no aggregation formation during chromatography, comprising:

• (a) mixing a fluorophore with a gold nanoparticle (GNP) to form a fluorophore-conjugated gold nanoparticle;
• (b) contacting the fluorophore-conjugated gold nanoparticle with each chromatographic resin of the plurality of chromatographic resins in a solution;
• (c) removing a supernatant and washing each chromatographic resin of the plurality of chromatographic resins with a washing buffer;
• (d) quantifying a level of fluorescence intensity of each chromatographic resin of the plurality of chromatographic resins;
• (e) measuring a level of hydrophobicity of each chromatographic resin of the plurality of chromatographic resins, wherein the level of the fluorescence intensity from (d) is indicative of the level of hydrophobicity of each chromatographic resin of the plurality of chromatographic resins;
• and
• (f) selecting the chromatographic resin of the plurality of chromatographic resins having the level of hydrophobicity which leads to the low or no aggregation formation during chromatography purification of the protein of interest.