Biosensor potentiometric cell-based

Immimodiagnostics and enzyme biosensors are two of the leading technologies that have a greatest impact on the food industry. The use of these two systems has reduced the time for detection of pathogens such as Salmonella to 24 hr and has provided detection of biological compounds such as cholesterol or chymotrypsin [15]. Biosensors analyses Beta lactams in milk and presence of urea in milk that lead to production of synthetic milk, the biocomponent part of the urea biosensor is an immobilized urease yielding bacterial cell biomass isolated from soil and is coupled to the ammonium ions selective electrodes of a potentiometric transducer. The membrane potential of all types of potentiometric cell based probes is related to the activity of electrochemically-detected product [16]. 

Unfortunately, the catalytic direct oxidation of CySH at the above solid electrode surface is kineticaUy slow and needs an overpotential. Hassan et al. (2007) developed a new, fast, simple, and highly selective potentiometric biosensor to determine the CySH in Tricho-sporon jirovecii yeast cells. Deng et al. constructed the boron-doped CNT-modified electrode for the electrocatalytic determination of CySH using chronoamperometric method. Ardakani et al. constructed a carbon paste electrode modified with quinizarine for the measurement of cysteine in the presence of tryptophan and measured the CySH in blood samples and CySH tablets. The common biological interfering substrates perhaps interfere and reduce the sensitivity of the CySH detection. Therefore, it is important to look for the electrocatalytic oxidation that might decrease the overpotential and increase the sensitivity of CySH detection. Earher, we studied the thiol oxidase-peroxidase activities of SOD. Based on that, we have developed a novel method for the measurement of CySH. 

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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