Tham khảo tài liệu 'new perspectives in biosensors technology and applications part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 382 New Perspectives in Biosensors Technology and Applications etc. Then such signal must me amplified and then processed. This amplifier module is the detector stage c . Thinking in electrical signals an amplifier stage is used to amplify the biological signal which is generally very low. Then d is the electronics module which has the role to process such measurements. Finally e the results are presented thanks to a user-friendly interface to visualize the data. Fig. 6. Generic components of a biosensor. Electrochemical biosensors Electrochemical biosensors are the largest group of chemical sensors. All of them are based on fixing some variables of the electrochemical cell and check how the other variables change with the fluctuations of the controlled variables. These biosensors are normally based on enzymatic catalysis of a reaction that produces or consumes electrons such as enzymes are rightly called redox enzymes . The sensor substrate usually contains three electrodes a reference an active or working and a counter or auxiliary electrode. Electrochemical sensors allow three main different configurations voltammetric potentiometric and conductrometric measurements. Voltammetric biosensors are those based on the measurement of the current-voltage variations. Voltammetric measurements typically consist of a three-electrode arrangement. Measurement of current occurs at the redox electrode as a function of the electrode potential. The solution must contain electro active species that can undergo electrode reaction. Amperometric biosensors are a particular case of them where is determined electrical currents associated with a redox process where a fixed voltage in the sensor is applied. In potentiometric biosensors the electrode and solution are in chemical equilibrium the current flow is near zero and a voltage is measured relative to a reference electrode. Conductometric biosensors are based on the measurement of the variations of the conductance with the .
