Linear sweep anodic stripping voltammetry
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A hapten-protein conjugate with copper nanoparticles (Hap-Car-BSA@CuNPs) was first synthesized in the present work for the determination of carbaryl. The copper nanoparticles (CuNPs) of the conjugate were used as electrochemical labels in the direct solid-phase competitive determination of carbaryl residues in flour from different crops. The signal was read by linear sweep anodic stripping voltammetry (LSASV) of copper (through the electrochemical stripping of accumulated elemental copper) on a gold-graphite electrode (GGE). To form a recognition receptor layer of monoclonal antibodies against the carbaryl on the surface of the GGE, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and 1-hydroxy-2,5-pyrrolidinedione (NHS) were used as the best covalent cross-linkers. The concentrations of the antibodies and the Hap-Car-BSA@CuNPs conjugate were optimized for carbaryl detection by the electrochemical immunosensor. The electrochemical immunosensor can be used for highly sensitive determination of carbaryl residues in flour samples in the concentration range 0.8-32.3 μg·kg-1, with a limit of detection 0.08 μg·kg-1. The present work paves the path for a novel method for monitoring carbaryl in other food products, drinks, and soil samples.
This work reports for the first time a significantly improved and simplified electrochemical immunoassay to detect antibodies to tick-borne encephalitis virus (TBEV) using a 96-well microtiter plate as a platform for immobilization and silver nanoparticles (AgNPs) as electrochemical labels. The electrochemical assay is performed by detecting the elemental silver oxidation signal where the electroactive signalling silver species are released from the bioconjugates (Ab@AgNP, AbS@AgNP, and ProteinA@AgNP). For this purpose, AgNPs were synthesized and further tagged with biomolecules (antibodies to TBEV, cleaved antibodies to TBEV, and protein A). Signal is read by linear sweep anodic stripping voltammetry (LSASV) of silver ions (through the electrochemical stripping of accumulated elemental silver) on a graphite electrode (GE). AbS@AgNP was chosen as the best option for the new electrochemical immunoassay. The results of electrochemical measurements demonstrated that voltammetric signal increased with the increasing concentration of target antibodies to TBEV within the range from 100 to 1600 IU mL-1, with a detection limit of 90 IU mL-1. To verify the practical application of the novel electrochemical immunosensor, the quantity of immunoglobulins against TBEV in human serum was checked. The results may contribute to the development of alternative methods for monitoring TBEV in biological fluids.
- MeSH
- elektrochemické techniky metody MeSH
- imunoanalýza metody MeSH
- klíšťová encefalitida diagnóza virologie MeSH
- kovové nanočástice chemie MeSH
- lidé MeSH
- protilátky virové analýza MeSH
- stříbro chemie MeSH
- viry klíšťové encefalitidy imunologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
A highly effective way to improve the prognosis of viral infectious diseases is early detection of antibodies to various viral pathogens in biological fluids. Among a wide range of viral pathogens, tick-borne encephalitis virus (TBEV) attracts a special attention. This work reports a comparison between two bioanalytical methods (enzyme‑linked immunosorbent assay (ELISA) and voltammetric immunoassay) to determine antibodies to TBEV in a human blood serum. In these assays, the detected molecule binds to the conjugate which is labelled with enzyme (in ELISA) or silver nanoparticles (in voltammetric immunoassay). In the ELISA, the signal corresponding to a colour-producing substrate (3,3',5,5'-tetramethylbenzidine) through an enzymatic reaction is detected using a spectrophotometer at a wavelength of 450 nm. In the electrochemical immunoassay, the signal is read by the linear sweep anodic stripping voltammetry (LSASV) of silver ions (through the electrochemical stripping of accumulated elemental silver) on a graphite composite electrode. The results of both measurements demonstrated that signals increased with the increasing concentration of the target antibodies to TBEV within the range from 100 to 1600 IU mL–1. Detection limits for ELISA and voltammetric assay were 30 and 90 IU mL–1, respectively. The practical application of both immunoanalytical approaches has been verified by determining the amount of antibodies to TBEV in the human blood serum. The obtained results clearly showed an excellent agreement between the detected concentration values of antibodies to TBEV obtained by the electrochemical method and by the standard ELISA method.
