Cytochrome biosensor

Biosensors based on direct electron transfer of proteins cytochrome c... 

N. Bistolas, U. Wollenberger, C. Jung, and F.W. Scheller, Cytochrome P450 biosensors - a review. Biosens. Bioelectron. 20, 2408-2423 (2005). 

E.I. Iwuoha, S. Joseph, Z. Zhang, M.R. Smyth, U. Fuhr, and P.R. Ortiz de Montellano, Drug metabolism biosensors electrochemical reactivities of cytochrome CYP101 immobilised in synthetic vesicular systems. J. Pharm. Biom. Anal. 17, 1101-1110 (1998). 

Additives such as polyethylene glycol, cationic antibiotics, polymers, small uncharged molecules, and negatively charged proteins have been used extensively in order to avoid the denaturing of enzymes or to improve the sensitivity and operational stability of biosensors. DNA has been proposed as an additive to improve the response and stability of biosensors based on CP. The biomolecules studied, such as tyrosinase [93], peroxidase [94], cytochrome C [95], have been shown to improve its performance by using adsorbed DNA within CP as an additive. 

Ferrocenyl-based polymers are established as useful materials for the modification of electrodes, as electrochemical biosensors, and as nonlinear optical systems. The redox behavior of ferrocene can be tuned by substituent effects and novel properties can result for example, permethylation of the cyclopentadienyl rings lowers the oxidation potential, and the chaige transfer salt of decamethylfer-rocene with tetracyanocthylene, [FeCpJ]" (TCNE], is a ferromagnet below = 4.8 K, and electrode surfaces modified with a pentamethylferrocene derivative have been used as sensors for cytochrome c These diverse properties have provided an added impetus to studies on ferrocene dendrimers. 

Our research group recently approached the problem of radical determination starting from the determination of oxygen free radicals, in particular superoxide radical, and assembling several new kinds of electrochemical sensors and biosensors suitable for this purpose [21-24]. Firstly, a voltammetric system based on the detection of reduced cytochrome c this system was also applied to develop a... 

V. Shumyantseva, G. Deluca, T. Buiko, S. Carrara, C. Nicolini, S.A. Usanov and A. Archakov, Cholesterol amperometric biosensor based on cytochrome P450scc, Biosens. Bioelectron., 19 (2004) 971-976. 

A.K. Abass, J.P. Hart and D. Cowell, Development of an amperometric sulphite biosensor based on sulphite oxidase with cytochrome c, as electron acceptor, and a screen-printed transducer, Sens. Actuators B Chem., 62 (2000) 148-153. 

A practical approach for toxicity screening combines bioactivation and DNA damage detection into a single biosensor for toxicity screening. To make these types of sensors, ultrathin films (20—4-0 nm thick) containing myoglobin or cytochrome P450cam and DNA were... 

An alternative approach, adopted by Albery et al. [59-61], is to determine the mechanism giving rise to the sensor response and to use this information together with the measured data at short times to calculate the final response. This was used for an electrochemical sensor system incorporating cytochrome oxidase where the steady-state responses of the measurement system were insufficiently fast for useful measurement of respiratory inhibitors such as cyanide, hydrogen sulphide, etc. By using mechanistic information, it was possible to successfully calculate the concentration in a test sample by real-time analysis of the sensor signals at short times after exposure to the test sample. The analysis could cope with the gradual loss of enzyme activity commonly found in these biosensor devices. 

For a potential application of cytochromes P450 in bioreactors or biosensors an interesting alternative is to substitute the biological electron donators by artificial ones Hke electrochemical [73,74,77,174] or... 

Free radical biosensors may help to investigate the role of O2 and NO as cellular messengers by the direct, real-time measuring of free radical production directly as cell signal and in relation to stimuli to which the cell is exposed. Two types of biosensors have been developed. The first exploits the highly specific reaction of superoxide dismutase [69], while the other type is based on the cytochrome c reduction by O2 [53-55,143,147]. A further alternative uses protoporphyrin IX adsorbed to carbon material [263]. Here, however, peroxide is a strong interferent. 

The elucidation of the potential biological role of NO has led to intensive work on techniques which can provide a fast, sensitive and selective detection of NO. The binding of NO to heme centres of cytochrome c [43,56], myoglobin [59], and haemoglobin [57] is the basis for NO biosensors. 

The reaction of peroxide with ferrous heme iron is the basis of electrocatalytic peroxide sensors. A selection that gives a representative overview of the biomolecules and transducers is included in Table 2.5. Peroxidase, catalase, haemoglobin, cytochrome c, microperoxidase and hemin can all be explored for peroxide measurement. Most papers on DET-based biosensor are related to peroxide detection in a variety of environments with peroxidases. 

Ti02 nanotubes composite electrode has been constructed for effective immobilization of cytochrome c and successful realization of its direct electrochemistry and electrocatalysis. The immobilized Cyt c/Ti02 bioactive electrode exhibits favorable electrocatalytic activity toward the reduction of H202 with good stability and sensitivity. The linear range was obtained is 2 x 10"6 to 3.49 x 10 mol /L"1 with detection limit of 1.21 x 10 6 mol/L"1. The fabricated biosensor retains 98.7% of the initial response after 30 days [27],... 

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