Development of a Bacterial Enzyme‐Based Biosensor for the Detection and Quantification of Selenate

Abstract

An enzymatic biosensor has been developed for the determination of selenate (SeO 4 2À ), in which selenate reductase (SeR) is chemically attached to a gold disk electrode by lipoic acid N-hydroxysuccinimide ester as linker, allowing the catalytic reduction of the SeO 4 2À to SeO 3 2À . Modification of the gold electrode was characterized by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), and electrochemistry. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements were performed in different buffers for selenate determination. Under optimum conditions, the calibration curve was linear over the range 7.0-3900.0 μg L À 1 with limits of detection and quantification of 4.97 and 15.56 μg L À 1 , respectively. The possible interference of the relevant oxyanions SO 4 2À , NO 3 À , NO 2 À , PO 4 3À and AsO 4 3À in the determination of SeO 4 2À was studied. Finally, the proposed biosensor was used to determine SeO 4 2À with recovery between 95.2 and 102.4 % in different real water samples.

Aptamer and Electrochemical Aptasensor towards Selenate Ions (SeO₄^2-)

“…Therefore, it is desirable to develop electrochemical sensors with enhanced selectivity, e.g., by designing and introducing selective bioreceptors with an affinity for selenium species. There are only a few such attempts described in the literature [29,30]. One of them is the approach proposed by Motlagh et al, who developed enzymatic gold nanodendrite biosensor.…”

“…Selenate reductase immobilized on the electrode surface reduces selenate to selenite ion, which, as an electroactive compound [31], is then detectable by CV and DPV voltammetry [29]. A similar approach is described by the same author in [30], where instead of a pure enzyme, the bacterial strains capable of selenate reduction were used. A different approach in biosensors development, instead of reaction catalyzed by specific enzymes, is the use of receptors that will express high affinity toward given analyte, selenate ion (SeO4 2-), and the same its binding in the receptor layer.…”

Aptamer and Electrochemical Aptasensor towards Selenate Ions (SeO42−)

“…Therefore, it is desirable to develop electrochemical sensors with enhanced selectivity, e.g., by designing and introducing selective bioreceptors with an affinity for selenium species. Only a few such attempts have been described in the literature [ 29 , 30 ]. One of them is the approach proposed by Motlagh et al, who developed an enzymatic gold nanodendrite biosensor.…”

“…Selenate reductase immobilized on the electrode surface reduces selenate to selenite ion, which, as an electroactive compound [ 31 ], is then detectable by CV and DPV voltammetry [ 29 ]. A similar approach is described by the same author in [ 30 ], where, instead of a pure enzyme, the bacterial strains capable of selenate reduction were used. A different approach in biosensor development, instead of reaction catalyzed by specific enzymes, is the use of receptors that express high affinity toward a given analyte, selenate ion (SeO 4 2− ), and its subsequent binding in the receptor layer.…”