Patent ID: 7003184

Claim:
A body compatible fiber optic sensor probe for invasive medical use, the probe including: a fiber; a sensing location at which the fiber is configured to provide at least one detectable changeable optical property responsive to a strain within the fiber; at least one sensing element which undergoes a volumetric change in response to an in body parameter to be sensed; wherein the sensing element is coupled to the fiber in such a way that the volumetric change induces the strain within the fiber so as to vary the detectable changeable optical property; wherein said fiber has a fiber cladding and comprising at least one sensing location provided with a sensing element in the form of a reactive coating which is disposed directly or indirectly on the fiber cladding, and wherein the coating is configured to create a strain within the fiber responsive to at least one body parameter to be measured, the strain providing a change in at least one detectable optical property of the fiber; said probe further comprising a protective membrane arranged over the reactive coating, said membrane allowing measurement of a particular parameter but providing in use a barrier between said coating and a body material, wherein the membrane is arranged to allow selected target molecules to diffuse from the body side through to the coating material forming the sensing element.