The invention provides a tissue engineering scaffold for application to a wound, the tissue engineering scaffold comprising a tissue regeneration matrix layer (1) for contacting the wound and a protective backing element (2) bonded to the tissue regeneration matrix layer, the tissue regeneration matrix layer (1) being formed from a porous biodegradable material capable of taking up cellular material from the wound and supporting tissue generation from the cellular material, and the protective backing element (2) being formed from a water-impermeable material wherein the protective backing element is provided with at least one cavity (4) therein containing an aqueous medium, the channel or cavity (4) being in fluid communication with the tissue regeneration matrix layer so that one or more biomarker substances from the tissue regeneration matrix layer can diffuse into the aqueous medium the cavityand wherein the protective backing element (2) is configured to allow aqueous medium to be withdrawn from the cavity for analysis.
