Chromatography matrix

1. A separation matrix for purification of biomacromolecules, comprising a plurality of particles having a core region and a shell region, wherein:

a) said shell region is accessible to a target biomacromolecule, wherein said shell region does not comprise polymers grafted to a porous support material and does not comprise polymers grafted to said shell;

b) said core region is less accessible to said target biomacromolecule than said shell region; and

c) said core region comprises at least 50 mg/ml of a vinyl polymer grafted to the porous support material and comprising residues of at least one polymerizable monomer, wherein said vinyl polymer comprises vinyl amide monomer residues selected from the group consisting of N-vinyl pyrrolidone, N-vinyl caprolactam, N-vinyl formamide and N-vinyl acetamide.

2. The separation matrix of claim 1 , wherein said core region is substantially inaccessible to said target biomacromolecule.

3. The separation matrix of claim 1 , wherein a diffusion rate for said target biomacromolecule in the core region is less than 10% of the diffusion rate for said target biomacromolecule in the shell region.

4. The separation matrix of claim 1 , wherein said target biomacromolecule is a protein with a molecular weight of over 5 kDa.

5. The separation matrix of claim 1 , wherein said target biomacromolecule is an immunoglobulin.

6. The separation matrix of claim 1 , wherein said shell region has an average thickness (d) of 1-15 micrometers.

7. The separation matrix of claim 1 , wherein said shell region has an average thickness of 0.5 to 6% of the diameter or the sphere-equivalent diameter of said particles.

8. The separation matrix of claim 1 , wherein said core region has a molecular weight cutoff for globular proteins of 1 to 500 kDa.

9. The separation matrix of claim 1 , wherein said particles are substantially spherical.

10. The separation matrix of claim 1 , wherein said particles have a volume-weighted median diameter of 10-400 micrometers.

11. The separation matrix of claim 1 , wherein said shell region and said core region both comprise said porous support material.

12. The separation matrix of claim 11 , wherein said porous support material comprises a polysaccharide.

13. The separation matrix of claim 12 , wherein said polysaccharide comprises agarose or agar.

14. The separation matrix of claim 12 , wherein said polysaccharide is crosslinked.

15. The separation matrix of claim 1 , wherein said vinyl polymer is grafted to said support material via bonds or linkers.

16. The separation matrix of claim 1 , wherein said vinyl polymer comprises N-vinyl pyrrolidone monomer residues.

17. The separation matrix of claim 1 , wherein said shell region comprises ligands capable of binding said target biomacromolecule.

18. The separation matrix of claim 17 , wherein said ligands comprise positively or negatively charged groups.

19. The separation matrix of claim 17 , wherein said ligands comprise hydrophobic groups.

20. The separation matrix of claim 17 , comprising multimodal ligands.

21. The separation matrix of claim 17 , wherein said ligands comprise affinity groups.

22. The separation matrix of claim 17 , wherein said shell region comprises 10-20 000 micromol/ml ligands.

23. The separation matrix of claim 4 , wherein said protein has a molecular weight of over 20 kDa.

24. The separation matrix of claim 5 , wherein said target biomacromolecule is IgG.

25. The separation matrix of claim 15 , wherein said linkers have a structure selected from the group consisting of structures I, II, III, IV or V:

Sup-O-CH 2 -CH 2 -CH 2 -Pol (I)

Sup-O-CH 2 -CH(CH 3 )-Pol (II)

Sup-O-CH 2 -CHOH-CH 2 -O-CH 2 -CH 2 -CH 2 -Pol (III)

Sup-O-CH 2 -CHOH-CH 2 -O-CH 2 -CH(CH 3 )-Pol (IV)

Sup-O-Pol (V),

wherein Sup denotes the support material and Pol the vinyl polymer.

26. The separation matrix of claim 20 , wherein said multimodal ligands are selected from the group consisting of N-benzyl-N-methyl ethanolamine, N-benzoyl homocysteine, 4-mercaptoethyl pyridine, p-aminobenzamidoacetic acid, tryptophan and phenylalanine.

27. A method of manufacturing a separation matrix of claim 1 , comprising the steps of:

a) providing a plurality of particles comprising a porous support material with grafting sites;

b) inactivating said grafting sites in a shell region;

c) incubating said particles in a composition comprising a polymerizable monomer wherein said polymerizable monomer is a vinyl amide; and

d) initiating polymerization of said polymerizable monomer.

28. The method of claim 27 , further comprising, before step a), a step a′) of introducing grafting sites on a porous support material.

29. The method of claim 27 , further comprising a step f) of reacting said particles with a ligand precursor reagent to couple ligands to said shell region.

30. The method of claim 27 , wherein said porous support material comprises carbon-bound hydroxyl groups and wherein said method comprises:

in step b) reacting said particles with an allylation reagent to obtain at least 50 micromole/ml allyl groups covalently attached to the particles; and

in step c) reacting said particles with a halogen for a period of up to 30 minutes and then with an alkaline aqueous solution.

31. The method of claim 27 , wherein said vinyl amide is N-vinyl pyrrolidone.

32. A method of separating a target biomacromolecule, comprising the steps of:

a) providing a sample comprising said target biomacromolecule;

b) conveying said sample through a column packed with the separation matrix of claim 1 ;

c) optionally conveying a wash liquid through said column; and

d) conveying an eluent through said column and recovering said target biomacromolecule in an eluate.

33. The method of claim 32 , wherein a flow velocity through the column in step b) and/or d) is at least 70 cm/h.