- Bio-Medical Sensors are used in 3 major areas:
- For identification and measurements, biological substances bio sensor are used.
- Bio-Instruments are surgical tools.
- Bio- Analytical system for testing and diagnosis.
- The Bio Medical Sensor consists of input signals, micro sensing element, transduction unit and output signals.
- Input Signal: The biological sample for e.g. Blood Sample or Body Fluid sample which is typically in micro- liters or nano-litre.
- Micro Sensing Element:: It is a chemical that react with the sample.
- Transduction Unit: The product of chemical reaction between sample and sensing element will be converted into electrical signal (mV or mA)
- Output Signal: It is an electric signal usually in mV.
Examples of Bio-Medical Sensor:
The following figure shows a simple glucometer used of measuring the glucose concentration of patient.
- The Glucose in the patient’s blood sample reacts with the O2 in the polyvinyl alcohol solution and produces H2O2.
- The H2 in H2O migrates towards Pt.Film (Platinum) in an electrolysis process and builds up layer at that electrode.
- The difference of potential between the 2 electrode due to the built up of H2 in the Pt. electrode relates to the amount of the glucose in the blood sample.