Abstract: The present invention provides an indicator for the in-situ detection of the presence of a lysozyme or a microbe producing lysozyme at a location. The indicator comprises a layer (8) which is susceptible to degradation by lysozyme and a signaling layer (7) which is adapted to produce a detectable signal which indicates the presence of the lysozyme or the microbe producing lysozyme which is located at substantially the same location as the lysozyme or microbe. In use, the signaling layer is at least initially protected from contact with the lysozyme or microbe which is located at substantially the same location as the lysozyme or microbe by the degradable layer.

Abstract: The present invention provides an indicator for the in-situ detection of the presence of a substance or a microbe at a location. The indicator comprises a layer (8) which is susceptible to degradation by the substance or microbe or a first substance associated with the microbe and a signalling layer (7) which is adapted to produce a detectable signal which indicates the presence of the substance or microbe or a second substance associated with the microbe or a further substance which is located at substantially the same location as the substance or microbe. In use the signalling layer is at least initially protected from contact with the substance or microbe or the second substance associated with the microbe or the further substance which is located at substantially the same location as the substance or microbe by the degradable layer.