Wound dressing with impedance sensor

A wound dressing comprising:

• a wound sensor, and
• an external measurement device, the external measurement device being:
• coupled or configured to couple with the wound sensor, and configured to receive electrical measurement signals from the wound sensor and to determine impedance of a wound or wound fluid using the received electrical measurement signals,
• the wound sensor comprising:
• at least one electrode having a sensing surface and a signal carrying portion, the signal carrying portion being configured for carrying the electrical measurement signals from the sensing surface to the external measurement device, the signal carrying portion and the sensing surface both being disposed on an electrically insulating substrate having insulating properties of during use of the wound sensor;
• an insulating layer that covers said signal carrying portion, such that said signal carrying portion is positioned between the substrate and the insulating layer;
• and
• a non-adherent porous layer in direct contact with the sensing surface,
• wherein:
• said sensing surface is positioned between the substrate and the non-adherent porous layer that is in direct contact with the sensing surface, such that the non-adherent porous layer that is in direct contact with the sensing surface and the substrate at least partly define a bounded volume in which the sensing surface is provided;
• and
• the non-adherent porous layer directly overlies and contacts the said sensing surface, forms a wound contact surface, and collects a volume of wound fluid within the bounded volume that is measurable by the external measurement device using the at least one electrode to determine the impedance.