This invention relates to a wound dressing comprising a modified polymer, wherein the modified polymer comprises a polymer backbone covalently coupled to a compound of Formula (I): (I). X is a covalent bond or a linker; R1 is independently at each occurrence selected from halo, C1-3 alkyl, C2-3 alkenyl, C1-3 haloalkyl, -O-C1-3 alkyl, -O-C1-3 haloalkyl and CN; and n is 0, 1, 2 or 3. Also provided are a methods of making the wound dressing and uses of such a wound dressing. The invention also relates to a method for detecting the presence of bacteria in a wound comprising applying the aforementioned wound dressing to the wound and a method of forming a modified polysaccharide, said polysaccharide allowing for the detection of bacteria in a wound when part of a wound dressing.