A sensitive photosystem II-based biosensor for detection of a class of herbicides

Abstract

We have developed a biosensor for the detection of residual triazine-, urea-and phenolic-type herbicides, using isolated photosystem II (PSII) particles from the thermophilic cyanobacterium, Synechococcus elongatus, as biosensing elements. The herbicide detection was based on the fact that, in the presence of artificial electron acceptors, the light-induced electron transfer through isolated PSII particles is accompanied by the release of oxygen, which is inhibited by the herbicide in a concentration-dependent manner. The PSII particles were immobilized between dialysis membrane and the Teflon membrane of the Clark oxygen electrode mounted in a flow cell that was illuminated. Inclusion of the antibiotic chloramphenicol in the reaction mixtures prolonged, by 50%, the lifetime of the biosensor. The use of highly active PSII particles in combination with the flow system resulted in a reusable herbicide biosensor with good stability (50% of initial activity was still remaining after 35-h use at 25°C) and high sensitivity (detection limit for diuron was 5 × 10 −10 M).

Reversible immobilization of engineered molecules by Ni-NTA chelators

“…4, where the reoxidation rate of the reduced form of the electron acceptor is shown for CYS -NTA -PSII (chemically and electrochemically deposited) and crosslinked PSII (e.g using the BSA -GA matrix [5,6]). On the contrary, the lower peak could be explained with the redundant number of Ni + 2 heads that does not reflect in a significant increase of PSII molecules on the electrode surface.…”

Detection of explosive compounds using Photosystem II-based biosensor

“…At low temperature (4°C) and in the dark both BBY particles [31] and thylakoid membranes [36] can be stored for hundreds of hours. At room temperature the half-life of the immobilized BBY particles and thylakoids is reduced to tens of hours [10,11,34]. Our biosensor exhibited approximately 35% decrease of the photocurrent within 7 h. Thus, the stability of our biosensor is slightly better than that reported in [11].…”

“…The idea for such sensor is inspired by recent progress in the development of inexpensive and sensitive herbicide biosensors based on photosynthetic reaction centers (RC). Since using PS II for herbicides detection was proposed more than 20 years ago [7] this subject has been explored extensively [8][9][10][11][12][13][14][15]. It is important to note that the chemical structures of nitric explosives are fairly similar to those of the herbicides detectable by these biosensors (Fig.…”

“…Both intact thylakoids [7,8,32,34,35] and PS II-enriched BBY particles [10,11,31] have been used in electrochemical cells and herbicide biosensors. At low temperature (4°C) and in the dark both BBY particles [31] and thylakoid membranes [36] can be stored for hundreds of hours.…”

Selective real-time herbicide monitoring by an array chip biosensor employing diverse microalgae

“…These studies demonstrate the detection of these herbicides in the range of EU threshold values of 0.1 µg L −1 for individual herbicides using chlorophyll fluorescence-based techniques. Comparable detection limits were also achieved using immobilised cyanobacterial photosystem II particles in a biosensor (Koblizek et al, 1998). Although the biosensor system described here was capable of rapid detection of herbicides with a detection limit between 0.5 and 10 µg L −1 , our results would have to be 5-20 times more sensitive to meet the EU-directive for individual herbicides.…”