Mumbai University > Electronics Engineering > Sem 8 > MEMS Technology

Marks: 5M

1. 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.

1. The Bio Medical Sensor consists of input signals, micro sensing element, transduction unit and output signals.
2. Input Signal: The biological sample for e.g. Blood Sample or Body Fluid sample which is typically in micro- liters or nano-litre.
3. Micro Sensing Element:: It is a chemical that react with the sample.
4. Transduction Unit: The product of chemical reaction between sample and sensing element will be converted into electrical signal (mV or mA)
5. 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.

Working:

1. The Glucose in the patient’s blood sample reacts with the O2 in the polyvinyl alcohol solution and produces H2O2.
2. The H2 in H2O migrates towards Pt.Film (Platinum) in an electrolysis process and builds up layer at that electrode.
3. 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.