A biosensor for the detection of triazine and phenylurea herbicides designed using Photosystem II coupled to a screen‐printed electrode

Abstract

A biosensor for the detection of triazine- and phenylurea-type herbicides was constructed using isolated Photosystem II (PS II) complexes as a biosensing element. PSII isolated from the thermophilic cyanobacterium Synechococcus elongatus was immobilized on the surface of a screen-printed sensor composed of a graphite working electrode and Ag/AgCl reference electrode deposited on a polymeric substrate. The biosensor was mounted in a flow microcell with illumination. The principle of the detection was based on the fact that herbicides selectively block PSII electron transport activity in a concentration-dependent manner. Changes of the activity were registered amperometrically as the rate of photoreduction of an artificial electron acceptor. The setup resulted in a reusable herbicide biosensor with a good stability (half-life of 24 h) and limit of detection of approximately 10(-9) M for diuron, atrazine and simazine.

Structure‐based design of novel Chlamydomonas reinhardtii D1‐D2 photosynthetic proteins for herbicide monitoring

“…The minimization procedure implemented in VLifeMDS software applies an optimizer that uses Powell method till the energy gradient is >10 kcal/(mol  Å), thereafter it shifts to conjugate gradient method till it reaches 1 kcal/(mol  Å) and subsequent minimization below this gradient is done a The LOD was determined on the basis of 99% confidence intervals, which, assuming a normal distribution, corresponds to 2.6  standard error of the measurement (r). Using then the modified relationship for the Langmuir absorption isotherm, LOD can be calculated as LOD ¼ 2.6  r  I 50 /(100 À 2.6  r) as reported by Koblizek et al 29 using Broyden-Fletcher-Goldfarb-Shanno (BFGS) method to achieve the desired convergence.…”

Biosensors for environmental applications: Future development trends

“…veloped by Koblizek et al [34] exhibited, for example, selective sensitivity to phenylurea and triazine herbicides, whereas phenolic herbicides were not registered. Heavy metals were also able to inhibit the activity of the PSII biosensor, but their effect is usually found at much higher concentrations than those typical for herbicides.…”

Photosynthetic Proteins Created by Computational and Biotechnological Approaches in Biosensing Applications

“…15.12 Immobilization of thylakoids onto amino-polystyrene magnetic beads. Glutaraldehyde is the bifunctional linker that reacts with amino groups of both the beads and the thylakoids have been constructed using these particles: a Clark's oxygen electrode (Laberge et al 1999;Koblizek et al 1998) and a screen-printed carbon-silver electrode (Koblizek et al 2002) (Fig. 15.13).…”