Stimulus responsive polymers for the purification of biomolecules

1. A soluble stimulus responsive polymer selected from the group consisting of allylamine containing polymers and copolymers and allylamine containing polymers and copolymers modified with a benzyl group, wherein the polymer is capable of binding and precipitating a biomolecule of interest in a sample upon addition of a stimulus.

2. The stimulus responsive polymer of claim 1 , wherein the biomolecule of interest is a therapeutic polypeptide.

3. The stimulus responsive polymer of claim 1 , wherein the biomolecule of interest is an impurity present in a sample along with a therapeutic polypeptide.

4. The stimulus responsive polymer of claim 3 , wherein the impurity is selected from the group consisting of host cell protein, endotoxin, DNA, RNA, viruses, lipids, whole cells and cellular debris.

5. The stimulus responsive polymer of claim 1 ., wherein the stimulus is a multivalent ion.

6. The stimulus responsive polymer of claim 5 , wherein the multivalent ion is phosphate or citrate.

7. The stimulus responsive polymer of claim 3 , wherein the therapeutic polypeptide is an antibody.

8. The stimulus responsive polymer of claim 7 , wherein the antibody is a monoclonal antibody.

9. A method of separating a target molecule from o le or more impurities in a sample, wherein the method comprises the steps of:

(a) providing a sample comprising a target molecule and one or more impurities;

(b) contacting the sample with a soluble stimulus responsive polymer according to claim 1 , thereby to form a complex of polymer and the one or more impurities; and

(c) adding a stimulus to the sample, thereby to precipitate the complex out of solution,

thereby to separate the target molecule from one or more impurities.

10. The method of claim 9 , herein the method further comprises one or more filtration steps.

11. The method of claim 9 , wherein the method further comprises one or more chromatography step.

12. The method of claim 9 , wherein the stimulus is a multivalent ion.

13. The method of claim 12 , wherein the multivalent ion is phosphate or citrate.