Enzyme biosensors control

Application of electrochemical enzyme biosensors for food quality control... 

Connecting an electrode with a redox enzyme and controlling the dynamics of the resulting system is an important and an actively pursued objective. It indeed allows the transduction of specific chemical events taking place at the prosthetic group of the enzyme into easy-to-use electric signals or, conversely, to trigger and control enzymatic reactions by easy-to-manipulate potential and current variables. Applications may concern biosensors and preparative-scale transformations [1-6]. 

In principle, enzyme-based biosensors have potential application in the agro-food analysis, within three main areas that are food safety, food quality, and process control. The term food safety involves the concept of the production and marketing of harmless food, monitoring the presence of contaminants, such as residues of pesticides, fertilizers, heavy metals, and other toxic organic compounds also used as additives. Food quality is related not only to safety but mainly to nutritional value and acceptability. Thus, in this context freshness, appearance, flavor, texture, and composition are food characteristics that have to be controlled. Moreover, enzyme biosensors allow the determination and quantification, on-line, of compounds of interest in process control, such as fermentation, sugar, alcohols contents, and so on. 

Serra, B., A. J. Reviejo, and J. M. Pingarron. 2007. Application of electrochemical enzyme biosensors for food quality control. Compr. Anal. Chem. 49 255-298. 

The application of FIA and biosensors in environmental analysis is attractive because enzyme biosensors operate on the principle of inhibition. The process is economical because only small quantities of substrate are required and because the incubation, reaction and reactivation times can be controlled. The process can therefore yield high reproducibility. This method has been used to measure insecticide levels in sea water [269], Finally, FIA is particularly suitable for the construction of automated systems. 

In a biocatalytic biosensor the molecular recognition component is an enzyme. Enzymes, macromolecular catalysts that are manufactured by plants and animals, affect the rates of biochemical reactions. Virtually all of the millions of chemical reactions involved in Hfe processes have associated enzymes controlling the rates. CoUectively, there are several thousand enzymes known and perhaps many thousand more yet to be discovered. 

Biosensors ai e widely used to the detection of hazardous contaminants in foodstuffs, soil and fresh waters. Due to high sensitivity, simple design, low cost and real-time measurement mode biosensors ai e considered as an alternative to conventional analytical techniques, e.g. GC or HPLC. Although the sensitivity and selectivity of contaminant detection is mainly determined by a biological component, i.e. enzyme or antibodies, the biosensor performance can be efficiently controlled by the optimization of its assembly and working conditions. In this report, the prospects to the improvement of pesticide detection with cholinesterase sensors based on modified screen-printed electrodes are summarized. The following opportunities for the controlled improvement of analytical characteristics of anticholinesterase pesticides ai e discussed ... 

---