Biosensor is the system which is generally consists of the system which recognizes the biological samples in appropriate manner. Bio receptor makes interaction with the analytic and transducer help in the amplification of the signals and measureable signals can be displayed on the screen in the form of the electrical signals. Bio-receptor is a biological molecule such as the enzyme, antibody, protein, and nucleic acid which is commonly present in the living organism which is used in the recognition of the biological molecule. Different techniques play as the key role in the technologies for the specificity, for seeking the measurement analyte make interaction with the electrode of the sensor. Biological signal based Biosensor can be categorized as Immuno-biosensor, Enzyme Based biosensor, Nucleic acid /DNA based biosensor and Cellular based biosensor. In the body with the high specificity and the sensitivity the ability of to detect the physiological and the pathogenic related molecules offers a opportunity which is very powerful and helpful in the treatment of the disease with the early diagnosis. The metals such nickel, cobalt which play essential role and act as the catalyst and also stabilize the structure of biological molecule such as the bacterial cell wall and the proteins. The metals in the high concentration cause the toxicity in the blood.