Tag: Biomedical sensors and transducers

Polarizable vs. Non-Polarizable Electrodes

We may categorize electrodes into two possible types albeit theoretically: those that are perfectly polarizable and those that are perfectly non-polarizable. This categorization is based on what happens to an electrode when a current passes between it and the electrolyte. … Read More

Principle for Measurement of Partial Pressure of Carbon Dioxide

The electrodes used for measurement of partial pressure of CO2 in blood are based on measuring the pH as demonstrated in the figure below:

Principle of carbon dioxide sensor
Figure 1.0 principle of carbon dioxide sensor

The measurement is based on the fact that … Read More

Basic Features of Intravascular Fiber Optic Blood Gas Sensor

Intra-arterial blood gas sensors usually use a single or double fiber configuration. Typically, the matrix containing the indicator is attached to the end of the optical fiber. Because the solubility of O2 and CO2 gases, as well as … Read More

Commonly used EEG Electrodes

The most commonly employed electrodes for recording electroencephalographic signals from the brain (EEG) are cup electrodes and subdermal needle electrodes. Cup electrodes are fabricated from platinum or tin approximately 5-10 mm in diameter. These cup electrodes are filled with a … Read More

The Principles of Microbial Biosensors

Introduction

The underlying basis of a microbial biosensor is the close proximity between an immobilized microorganism that serves as a specific recognition element and an electrochemical or optical sensing transducer that is used to convert the biochemical signal into an … Read More

The Operation of Fiber-optic Based Blood Gas Sensors

To perform in vivo measurements and to steadfastly analyze blood gases, a small, stable, accurate and bio-compatible sensor is needed that can be inserted in the blood flow of an artery through an arterial cannula and remain in place for … Read More

The Principle of Surface Plasmon Resonance Sensors for Detection of Antibody & Antigen Interactions

When monochromatic polarized light for instance, from a laser source impinges on a transparent medium having a conducting metallized surface (e.g. Ag or Au), there is a charge density oscillation at the interface. When a light at an appropriate wavelength … Read More

Key Properties of Bioelectrodes

To record biopotentials, an interface is required between the electron-conducting copper wires connected to signal conditioning amplifiers and the ion-conducting environment of living organisms. Electrodes form this interface.

Some of the several kinds of electrodes are better than others … Read More

Basic Features of Enzyme Based Biosensors

Enzymes are the commonly used biological sensing element in the fabrication of various biosensors. Enzymes have unique properties and ability to accelerate chemical reactions inside biological cells. Most enzymes react only with specific substrates even though they may be contained … Read More

Fleisch Pneumotachometer Operation & Biomedical Application

Fleisch Pneumotachometer is one of the most common types of airflow transducers. It consists of a straight short-tube with a fixed screen obstruction in the middle that produces a slight pressure drop as the air is passed through the … Read More