A novel urea conductometric biosensor based on zeolite immobilized urease.

A new approach was developed for urea determination where a thin film of silicalite and zeolite Beta deposited onto gold electrodes of a conductometric biosensor was used to immobilize the enzyme. Biosensor responses, operational and storage stabilities were compared with results obtained from the standard membrane methods for the same measurements. For this purpose, different surface modification techniques, which are simply named as Zeolite Membrane Transducers (ZMTs) and Zeolite Coated Transducers (ZCTs) were compared with Standard Membrane Transducers (SMTs). Silicalite and zeolite Beta with Si/Al ratios 40, 50 and 60 were used to modify the conductometric electrodes and to study the biosensor responses as a function of changing zeolitic parameters. During the measurements using ZCT electrodes, there was no need for any cross-linker to immobilize urease, which allowed the direct evaluation of the effect of changing Si/Al ratio for the same type of zeolite on the biosensor responses for the first time. It was seen that silicalite and zeolite Beta added electrodes in all cases lead to increased responses with respect to SMTs. The responses obtained from ZCTs were always higher than ZMTs as well. The responses obtained from zeolite Beta modified ZMTs and ZCTs increased as a function of increasing Si/Al ratio, which might be due to the increased hydrophobicity and/or the acid strength of the medium.

[1]  J. Park,et al.  Microfabricated Conductometric Urea Biosensor Based on Sol‐Gel Immobilized Urease , 2000 .

[2]  Joseph Wang,et al.  Accumulation and voltammetric measurement of silver at zeolite-containing carbon-paste electrodes , 1988 .

[3]  N. Jaffrezic‐Renault,et al.  Urease-gelatin interdigitated microelectrodes for the conductometric determination of protease activity. , 2008, Biosensors & bioelectronics.

[4]  A. Walcarius.  Zeolite‐modified electrodes: Analytical applications and prospects , 1996 .

[5]  Oriented assembly and nanofabrication of zeolite A monolayers , 2009 .

[6]  J. Cabral,et al.  Probing the microenvironment of sol-gel entrapped cutinase: the role of added zeolite NaY. , 2008, Journal of biotechnology.

[7]  A. Tavolaro,et al.  Influence of zeolite PZC and pH on the immobilization of cytochrome c: a preliminary study regarding the preparation of new biomaterials. , 2009, Colloids and surfaces. B, Biointerfaces.

[8]  N. Jaffrezic‐Renault,et al.  Conductometric Microbiosensors for Environmental Monitoring , 2008, Sensors.

[9]  Asha Chaubey,et al.  Application of conducting polymers to biosensors. , 2002, Biosensors & bioelectronics.

[10]  M. Y. Arica,et al.  Immobilization of urease via adsorption onto L-histidine-Ni(II) complexed poly(HEMA-MAH) microspheres : Preparation and characterization , 2005 .

[11]  B. Akata,et al.  Preparation and characterization of zeolite beta-polyurethane composite membranes , 2007 .

[12]  D. C. Koningsberger,et al.  Influence of Si/Al Ratio on Catalytic Performance of (Co)Mo/Saponite Catalysts , 1999 .

[13]  M. Mcshane,et al.  Microcapsule biosensors using competitive binding resonance energy transfer assays based on apoenzymes. , 2005, Analytical chemistry.

[14]  Tao Yu,et al.  Controlled nanozeolite-assembled electrode: remarkable enzyme-immobilization ability and high sensitivity as biosensor. , 2006, Chemistry.

[15]  J. Cabral,et al.  Influence of the presence of NaY zeolite on the activity of horseradish peroxidase in the oxidation of phenol , 2007 .

[16]  K. B. Yoon,et al.  Micropatterning of Oriented Zeolite Monolayers on Glass by Covalent Linkage , 2000 .

[17]  S. Mintova,et al.  Nanoporous materials with enhanced hydrophilicity and high water sorption capacity , 2008 .

[18]  K. Sakaguchi,et al.  Selective adsorption of biopolymers on zeolites. , 2001, Chemistry.

[19]  A. Sayari,et al.  Adsorption of urease on PE-MCM-41 and its catalytic effect on hydrolysis of urea. , 2008, Colloids and surfaces. B, Biointerfaces.

[20]  Joseph Wang.  Carbon‐Nanotube Based Electrochemical Biosensors: A Review , 2005 .

[21]  B. Adhikari,et al.  Polymers in sensor applications , 2004 .

[22]  J. Kong,et al.  Nanozeolite-assembled interface towards sensitive biosensing , 2007 .

[23]  J. Park,et al.  Sol-gel-derived thick-film conductometric biosensor for urea determination in serum , 2000 .

[24]  G. Calzaferri,et al.  Copper-zeolite-modified electrodes: An intrazeolite ion transport mechanism , 1994 .

[25]  M. Taher,et al.  A new method for electrocatalytic oxidation of ascorbic acid at the Cu(II) zeolite-modified electrode. , 2009, Talanta.

[26]  J. Zhang,et al.  Effects of supporting electrolyte and zeolite co-cations on the electrochemical response of zeolite-modified electrodes , 1992 .