Biosensor enzyme-free

The determination of H202 is very important in many different fields, such as in clinical, food, pharmaceutical, and environmental analyses [202], Many techniques such as spectrophotometry, chemiluminesence, fluorimetry, acoustic emission, and electrochemistry methods have been employed to determine H202. Electrochemical methods are often used because of their advantages. Among these electrochemical methods, the construction of the mediator-free enzyme-based biosensors based on the direct electrochemistry of redox proteins has been reported over the past decade [203— 204], The enzyme-based biosensors, which use cyt c as biocatalyzer to catalyze H202, were widely studied. 

J. Sefconicova, J. Kahlik, V. Stefuca, et al, A filtration probe-free on-line monitoring of glycerol during fermentation by a biosensor device. Enzyme Microb. Technol, 42, 434 39 (2009). 

One of the promising potentials of SECM for biosensor research is the possibility to investigate immobilized enzymes independent of the communication to the electrode onto which they are immobilized. In fact, not too seldom, the immobilization of proteins onto electrode surfaces inhibits fast electron transfer reactions. SECM can be used to probe the enzymatic activity from the solution side of an immobilized enzyme film with a UME that is free of any cover layer. When designing an SECM experiment for the investigation of immobilized enzymes, one should consider the following guidelines. 

The second reaction gives a colored product that can be detected in a spectrophotometer at 555 nm. The free-enzyme FIA system used an enzyme-reagent solution as described in a previous work (4). The immobilized AOD (0.1 mL of AOD with 4.5 mL of phosphate buffer, pH 7.0) integrating the biosensor-FIA system worked with phosphate buffer (pH 7.0), HRP (0.5 mg/mL), and reagent solution consisting of 0.875 g/L of phenol and 0.305 g/L of 4-aminophenazone was added. 

---