American Scientific Publishers, Sensor Letters, 5(7), p. 731-738
DOI: 10.1166/sl.2009.1140
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The development of a new urea biosensor is obtained by covalent binding of urease and ferrocene ethyl amine as redox marker on electropolymerized copolypyrrole matrix formed by poly(N-hydroxyphtalimide-pyrrole-co-pyrrole). The biosensor was characterized by cyclic voltammetry and impedance measurements. The voltammogram shows a well redox signal with an anodic peak at 0.2 V and cathodic peak at 0.15 V attributed to the ferrocenyl group. The Nyquist diagram shows a large modification after enzyme and ethyl amine ferrocene link on the copolymer film. The ferrocenyl group shows high sensitivity of its electrochemical signal to pH change and it can be used as redox marker for urea detection. Amperometric and impedimetric response were measured as a function of urea concentration in PBS solution pH 7.0. It has been found that the amperometric and impedimetric biosensors show a linear response range from 0.01 to 0.30 mM of urea. The biosensor exhibited a response time of 40-60 s and was stable for about 28 days.