Patent ID: 7964415

Claim:
A method of conjugating a polyethylenimine polymer having a charge to one or more active moieties, comprising: (a) altering the charge on the polyethylenimine polymer with a charge modifying agent to form a charge-modified polyethylenimine; (b) chemically activating the charge-modified polyethylenimine with an activating agent to form a chemically-activated polyethylenimine; and (c) conjugating the chemically-activated polyethylenimine to one or more active moieties selected from the group consisting of streptavidin, polystreptavidin, avidin, glycoproteins, lectins, hormones, antigens, drugs, antibodies, antibody antigen binding fragments, RNA, DNA, oligonucleotides, photoproteins, enzymes, fluorophores, and combinations thereof; wherein the charge modifying agent has an anhydride functionality and alters the charge on the polyethylenimine polymer by grafting a functional group to the polyethylenimine polymer, said functional group not participating in steps (b) and (c), and wherein the activating agent is glutaraldehyde.