Chemical sensors enzyme-based biosensors with

A review of chemical sensors and arrays [6] focuses on conducting polymers as inherent receptors, the modification of conducting polymers with receptors, the use of conducting polymers as transducers as well as some applications in combinatorial and high-throughput assays. Fundamental aspects of redox-related conductivity and pH-sensitive conductivity are included, and applications to chemical- and enzyme-based biosensors are summarized based on analyte. A variety of detection methods (electrical, electrochemical, and optical) are surveyed. 

HPLC with UV-based diode array detection (DAD-UV) or electrochemical detection is normally used to determine ascorbic acid. Many types of electrochemical determinations of ascorbic acid have been proposed. Although the electrochemical determinations using enzyme-based biosensors exhibited high specificity and sensitivity, these methods suffer in the fabrication of the electrodes and in automatic analysis. Recently, chemically modified screen-printed electrodes have been constructed for the determination of ascorbic acid. This is one of the most promising routes for mass production of inexpensive, reproducible, and reliable electrochemical sensors. 

A MEMS-based biosensor is a biosensor which is realized by microfabrication technology and takes advantage of the small size. It incorporates a biological component with a physiochemical transducer such as a microsystem. It is a special class of chemical sensor that takes advantage of the high selectivity and sensitivity of biologically active materials. It involves immuno, enzyme and microorganism sensors. 

A sensor array for monitoring indicators of mannnalian cell metabolic status has been reported by Pemberton et al. [33], and is based on both enzyme-modified elements and chemical sensors for temperature, pH, and dissolved oxygen. The array, fabricated in a silicon platform using MEMS technology, consists of five-well sensor strips with a multipotentiostat to switch between potentiometric and amperometric measurement modes. Screen-printed biosensors for glucose and lactate were grafted onto two of the weUs. The authors envision applications to cell culture and cytotoxicity studies. 

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