Biosensors are analytical devices used to detect a biological component using a recognition element, transducer, and processing/display element. Biosensors are used in many different fields for a variety of applications, from blood glucose monitoring to the detection of airborne bacteria from a biological attack. But what actually makes up a biosensor?
The Recognition Element
This is the first major component of the biosensor. Its purpose is to ensure that the desired component of the analyte is collected for analysis by the rest of the system. Micro-organisms, DNA, enzymes, and even whole cells can be used for component recognition.
The biosensor component interfaces with the recognition element and provides for a means of converting the recognized elements into electrical signals. Electrochemical, piezoelectric, thermal, and optical are all different approaches to transduction.
The Display/Processing Element
Lastly is the display and processing element. This element connects to the output of the transducer, possibly through an amplifier depending on signal strength. The goal of this element is to take a signal and extract any useful information from it. Once processed, it is sent to the display.
Microfabrication is the process of fabricating miniature structures of micrometer scales and smaller and is used to manufacture items such as integrated circuits (ICs), microelectromechanical systems (MEMS), solar cells, etc. The major processes of microfabrication include lithography, doping, etching, bonding, and polishing.
At LeTourneau, the students use the following to produce the microfabrications:
LASI (LAyout System for Individuals) is a general purpose layout and design software originally intended for integrated circuits. It is versatile enough that it can be used for ICs, MEMS, other nanotechnologies, discrete devices, schematics, PC boards and project documentation drawings.
Photolithography is an optical method of transferring patterns onto a substrate, and it is a binary pattern transfer meaning that there is no gray-scale, color, or depth to the image. Below is the basic process used in photolithography.
Sputter deposition is the process of depositing thin layers of material such as gold, ranging from fractions of a nanometer to several micrometers in thickness, onto a substrate. It is used extensively in the manufacturing of ICs in order to deposit thin films of various metals.