The interaction of genotoxic environmental pollutant 2-nitrofluorene (2-NF) with double-stranded DNA has been studied using a hanging mercury drop electrode (HMDE) as an electrochemical sensor. Two types of DNA damage were investigated and electrochemically detected using cyclic voltammetry and differential pulse voltammetry: (i) DNA damage caused by the direct interaction with 2-NF and (ii) DNA damage caused by short-lived radicals generated by the electrochemical reduction of 2-NF. For the study of the direct interaction, the HMDE was modified by DNA and the interaction of DNA with 2-NF was studied after their mutual interaction right at the HMDE surface, or DNA was preincubated with 2-NF in solution and, subsequently, the interaction was studied voltammetrically. Using both detection techniques, the formation of DNA-2-NF complex was observed and the mutual interaction was interpreted as an intercalation between DNA base pairs. On the basis of obtained results, we suppose that expected formation of 8-oxoguanosine leads to guanosine-cytidine base pair interruption and DNA double-strand break formation. The binding constants (K) of the DNA-2-NF complex formed in solution and on the HMDE surface (DNA/HMDE) were determined from the changes in the voltammetric peaks of the studied analyte.
- MeSH
- DNA * metabolismus MeSH
- elektrody MeSH
- fluoreny MeSH
- poškození DNA MeSH
- rtuť * MeSH
- Publikační typ
- časopisecké články MeSH
In this study, a mercury meniscus-modified silver solid amalgam electrode was used for the first time for the detection of UV-induced DNA damage. The integrity of the double-stranded DNA (dsDNA) layer was detected indirectly using the evaluation of the methylene blue reduction within its accumulation into dsDNA after the UV irradiation of the biosensor surface with two different wavelengths (254 nm and 365 nm), monitored by differential pulse voltammetry. Moreover, a simple electrochemical characterization of the biosensor surface was performed using cyclic voltammetry of the redox indicator hexaammineruthenium chloride (RuHex) present in the solution. Electrochemical impedance spectroscopy (EIS) was used in both cases for the verification of results. Individual electrochemical signals depend on the time of biosensor exposure to UV irradiation as well as on the selected wavelengths and are different for both used types of dsDNA (salmon sperm and calf thymus). The highest degradation degree up to 60% was observed using sensitive EIS of methylene blue after 10 min irradiation of the biosensor at 254 nm. The use of RuHex seems to be less sensitive for the detection of dsDNA structural changes, when the degradation degree up to 40% was observed, using EIS at the same conditions.
- MeSH
- biosenzitivní techniky * metody MeSH
- DNA chemie MeSH
- elektrochemické techniky metody MeSH
- elektrody MeSH
- lidé MeSH
- methylenová modř chemie MeSH
- poškození DNA MeSH
- sperma MeSH
- stříbro * MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Metronidazole (MND) is an antibiotic drug used to treat severe bacterial infections (e.g., of the central nervous system, lungs and respiratory tract, digestive tract, or female genital organs). In this work, a new voltammetric method for the determination of MND on a silver solid electrode was developed. Under optimum conditions (Britton-Robinson buffer of pH 10.0 used as a supporting electrolyte and electrochemical regeneration of the working electrode surface applied to eliminate its passivation), a linear calibration dependence of MND was recorded in the concentration range from 1 to 400 μmol L−1, with the limits of detection (LOD) and quantification (LOQ) of 0.55 μmol L−1 and 1.8 μmol L−1, respectively.
- Klíčová slova
- voltametrie,
- MeSH
- elektrochemie metody MeSH
- léčivé přípravky analýza MeSH
- lidé MeSH
- metronidazol * analýza MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
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.
A highly effective way to improve prognosis of viral infectious diseases and to determine the outcome of infection is early, fast, simple, and efficient diagnosis of viral pathogens in biological fluids. Among a wide range of viral pathogens, Flaviviruses attract a special attention. Flavivirus genus includes more than 70 viruses, the most familiar being dengue virus (DENV), Zika virus (ZIKV), and Japanese encephalitis virus (JEV). Haemorrhagic and encephalitis diseases are the most common severe consequences of flaviviral infection. Currently, increasing attention is being paid to the development of electrochemical immunological methods for the determination of Flaviviruses. This review critically compares and evaluates recent research progress in electrochemical biosensing of DENV, ZIKV, and JEV without labelling. Specific attention is paid to comparison of detection strategies, electrode materials, and analytical characteristics. The potential of so far developed biosensors is discussed together with an outlook for further development in this field.
- MeSH
- biosenzitivní techniky * MeSH
- dengue * diagnóza MeSH
- Flavivirus * MeSH
- infekce virem zika * diagnóza MeSH
- japonská encefalitida * diagnóza MeSH
- lidé MeSH
- virus zika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
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
Voltammetric determination of Tartrazine (Tz) and Brilliant Blue FCF (BB) in their mixture using novel type of carbon black-polyethylene composite electrode (CBPCE) with renewable surface modified by carbon ink (CI) was developed. Electrochemical properties of the tested dyes were investigated in 0.1 mol L-1 Britton-Robinson (BR) buffer by cyclic voltammetry (CV) and linear scan voltammetry (LSV). Simultaneous determination of the dyes is based on the application of supporting electrolytes with different pH: 2.0 for Tz and 10.0 for BB. Under the optimum experimental conditions, linear concentration dependences in the concentration ranges from 0.037 to 1.38 μmol L-1 for Tz and from 0.025 to 2.52 μmol L-1 for BB were obtained by LSV in the first-order derivative mode. Limits of detection (LODs) for Tz and BB were 0.019 and 0.011 μmol L-1, respectively. The modified electrode showed good stability and reproducibility and was successfully applied for the determination of the mixture Tz and BB in a candy and soft drink products.
- Publikační typ
- časopisecké články MeSH
A new electroanalytical methodology was developed for the sensitive and selective determination of formaldehyde in wood-based products (WBPs), featuring an extraction process using a Headspace Liquid Acceptor System (HLAS), and detection by square-wave voltammetry (SWV) on unmodified screen-printed carbon electrodes (SPCEs). HLAS, here presented for the first time, captures and derivatizes formaldehyde released from the sample by using the acetylacetone reagent as acceptor solution. The product of formaldehyde with acetylacetone, in the presence of ammonium salt, is 3,5-diacetyl-1,4-dihydrolutidine (DDL) which we have found to be electrochemically active at unmodified SPCEs, generating a selective oxidation peak at +0.4 V. Detection and quantification limits of 0.57 and 1.89 mg kg-1 were obtained, together with intra- and inter-day precisions below 10% (as relative standard deviation, RSD). The methodology was used to determine formaldehyde content in seven WBPs, with similar results being obtained by the developed HLAS-SPCE method and the European standard method EN 717-3, with a profound reduction of total analysis time. The developed HLAS-SPCE combines the use of a new sample preparation procedure for volatiles with, as far as we know, the first determination of formaldehyde (as the derivative product, DDL) on unmodified SPCEs, offering a promising alternative for the determination of formaldehyde in WBPs and other samples.
- 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.
A new simple electrochemical immunosensor approach for the determination of antibodies to tick-borne encephalitis virus (TBEV) in immunological products was developed and tested. The assay is performed by detecting the silver reduction signal in the bioconjugates with antibodies (Ab@AgNP). Here, signal is read by cathodic linear sweep voltammetry (CLSV) through the detection of silver chloride reduction on a gold-carbon composite electrode (GCCE). Covalent immobilization of the antigen on the electrode surface was performed after thiolation and glutarization of the GCCE. Specific attention has been paid to the selection of conditions for stabilizing both the silver nanoparticles and their Ab@AgNP. A simple flocculation test with NaCl was used to select the concentration of antibodies, and the additional stabilizer bovine serum albumin (BSA) was used for Ab@AgNP preparation. The antibodies to TBEV were quantified in the range from 50 IU·mL-1 to 1600 IU·mL-1, with a detection limit of 50 IU·mL-1. The coefficient of determination (r2) is 0.989. The electrochemical immunosensor was successfully applied to check the quality of immunological products containing IgG antibodies to TBEV. The present work paves the path for a novel method for monitoring TBEV in biological fluids.
- MeSH
- elektrochemické techniky metody MeSH
- elektrody MeSH
- imunoanalýza metody MeSH
- klíšťová encefalitida diagnóza imunologie MeSH
- kovové nanočástice chemie ultrastruktura MeSH
- protilátky virové imunologie MeSH
- sérový albumin hovězí MeSH
- skot MeSH
- spektrofotometrie ultrafialová MeSH
- stříbro chemie MeSH
- velikost částic MeSH
- viry klíšťové encefalitidy imunologie MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
