The invention discloses a separation matrix for purification of biomacromolecules, comprising a plurality of particles (1) having a core region (2) and a shell region (3), wherein:
a) said shell region is accessible to a target biomacromolecule;
b) said core region is less accessible to the target biomacromolecule than the shell region; and
c) the core region comprises a grafted polymer comprising residues of at least one polymerizable monomer.