Isolated heparin or heparan sulphate oligosaccharide fragments having a chain length of at least 10 saccharides and no more than 50 saccharides, which are capable of binding BMP2, are disclosed. Also disclosed is the use of the same heparin or heparan sulphate oligosaccharide fragments in kits and pharmaceutical compositions, and the use of the same heparan sulphate oligosaccharide fragments in the repair and/or regeneration of connective tissue and bones, and the treatment of wounds.