Biochips are squares of glass, smaller than smallest postage stamp, covered with millions of DNA strand. Biochip is a tool allowing rapid screening of gene profile to detect genes. They are called gene microarrays. A biochip contains all known human genes.

Biochips are squares of glass, smaller than smallest postage stamp, covered with millions of DNA strand.

The type of transducer used in the sensors are 

Amperometric transducers detect change in current as a result of electrochemical oxidation or reduction. 

Glucose oxidase is widely used for the determination of free glucose in body fluids and in the food industry. It also has many applications and typically enzyme assays for biochemistry including biosensors. 

Bioreceptor interacts with the specific analyte of interest to produce an effect which is measured by the transducer. The main reasons for the common use of enzymes in biosensors are:

A- Electrochemical biosensors are simple tools which are utilized to determine the measurement of electronic current or conductance changes done by the bio-electrodes. The electrochemical sensor converts the electrochemical information into an analytical signal. This type of biosensor is generally made up of two basic parts - a biological component & an electronic component.

DNA biosensors have various applications, commonly used for medical diagnostics, forensic science, agriculture, or even environmental clean-up efforts. It function as the two strands of DNA stick to each other by virtue of chemical attractive forces and that is, two strands that match up at every nucleotide position gives rise to a fluorescent signal that is then transmitted to a signal generator.

Electrochemical biosensors are those biosensors that are mostly based on enzymes and catalyses the reaction that produces or consumes electrons. The reactions are redox types and the enzymes that catalyze these oxidations are called dehydrogenases.

In molecular biology, biochips are essentially miniaturized laboratories that can perform hundreds or thousands of simultaneous biochemical reactions. Biochips enable researchers to quickly screen large numbers of biological analytes for a variety of purposes, from disease diagnosis to detection of bioterrorism agents.