Patent ID: 7060804

Claim:
A method for isolating at least one of proteins and protein and nucleic acid associations, from a sample, comprising: bringing said sample into contact with magnetic colloidal particles to form a mixture, said magnetic colloidal particles comprising a core and an envelope in which: the core is magnetic and is coated with at least one polymer comprising functional groups X chosen from amine, hydroxyl, thiol, aldehyde, ester, anhydride, acid chloride, carbonate, carbamate, isocyanate and isothiocyanate groups, or mixtures thereof, at least one fraction of which has reacted with other functional groups of the envelope, and the envelope comprises a polymer bearing ionizable functional groups, Z and Z′, which may be identical or different, chosen from amine, carboxylic acid, ester, anhydride, aldehyde, thiol, disulfide, α-halocarbonyl, sulfonic acid, maleimide, isocyanate and isothiocyanate groups, which have partially reacted with the functional groups X of the core; incubating said mixture under predetermined conditions, and applying a magnetic field to separate at least one of proteins and protein and nucleic acid associations complexed on said colloidal particles from the mixture.