The present invention relates to branched polymer comprising a support moiety and at least three block co-polymer chains covalently coupled to and extending from the moiety, wherein: (i) each of the at least three block co-polymer chains comprise (a) a cationic polymer block that is covalently coupled to a hydrophilic polymer block, or (b) a cationic polymer block that is covalently coupled to a hydrophobic polymer block, said hydrophobic polymer block being covalently coupled to a hydrophilic polymer block and (ii) at least one of said covalent couplings associated with each of said block co-polymer chains is biodegradable.
