ABSTRACT
Any instrumentation system can be described as having three fundamental components: a sensor, a signal
processor, and a display and/or storage device. Although all these components of the instrumentation system
are important, the sensor serves a special function in that it interfaces the instrument with the system being
measured. In the case of biomedical instrumentation, a biomedical sensor (which in some cases may be referred
to as a biosensor) is the interface between the electronic instrument and the biological system. There are some
general concerns that are important for any sensor in an instrumentation system regarding its ability to
effectively carry out the interface function. These concerns are especially important for biomedical sensors
because the sensor can affect the system being measured and the system can affect the sensor. Sensors must be
designed so that they minimize their interaction with the biological host. It is important that the presence of the
sensor does not affect the variable being measured in the vicinity of the sensor via interaction between the sensor
and the biologic system. If the sensor is placed in a living organism, that organismwill probably recognize it as a
foreign body and react to it. This may change the quantity being sensed in the vicinity of the sensor so that the
measurement reflects a reaction to the foreign body rather than a central characteristic of the host.
