A novel methodology to create covalently linked polypeptide-siloxane hybrid materials by controlled n-carboxyanhydride ring opening polymerisation is disclosed. Poly-L-glutamic acid and poly-L-lysine conjugated products were formed that possessed excellent surface wettability. In addition, the poly-L-lysine-siloxane hybrids formed demonstrated bactericidal attributes against gram-positive Staphylococcus aureus and gram-negative Escherichia coli. It is anticipated that these materials may be of significance for the generation of hydrophilic siloxane-containing polymers that are commonly employed in contemporary medical devices.