Chemiluminescent biosensors based on porous supports with immobilized peroxidase.

Combining a sensitive and fast chemiluminescence detection method with novel immobilization methods for horseradish peroxidase (HRP) has enabled us to develop sensitive sensors for hydrogen peroxide and the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). HRP biospecific immobilization was shown to have well-defined advantages in terms of a higher specific activity of the enzyme of the surface and a greater sensitivity in the enhanced chemiluminescence (ECL) reaction. The lower detection limit for hydrogen peroxide was 0.025 nmol with HRP immobilized on nitrocellulose membrane through avidin-biotin linkage. An immunosensor for the detection of 2,4-D provides a lower detection limit of 0.2 microgram/l with specific antibodies covalently immobilized on photoactivated nylon. The assay with chemiluminescent detection was also characterized with a wider concentration range when compared with the colorimetric assay.

[Joint immobilization of L-lysine-alpha-oxidase and peroxidase on porous membrane carriers]. / Sovmestnaia immobilizatsiia L-lizin-alpha-oksidazy i peroksidazy na proistykh membrannykh nositeliakh.

The goal of the present study was the development of the optimal method of co-immobilization of two enzymes: L-lysine alpha-oxidase from Trichoderma sp. and horseradish peroxidase. Commercial nitrocellulose, nylon and N+ nylon membranes were used as carriers. The immobilization was carried out either by absorbtion or by covalent binding with aldehyde groups. The aldehyde groups were attached to the surface of the carriers by UV-irradiation of membranes in the presence of p-azidotetrafluorobenzaldehyde. The optimal concentrations of reagents, enzymes and reaction conditions were found. The membranes with the co-immobilised L-lysine alpha-oxidase and peroxidase were shown to be useful for the determination of L-lysine concentrations.