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

Cholesterol plays a vital role in a human body. It is known as one of the most important sterols, because it forms cell walls and participates in signal transduction. Moreover, cholesterol was recognized as biomarker of cardiovascular diseases and of some metabolic disorders. As a result, cholesterol blood levels should be controlled in a variety of diseases such as ischemic heart disease, cerebrovascular ischemia, stroke, hypertension, type II diabetes, and many others. Hence, the accurate cholesterol quantification plays an important role in diagnosis and treatment of these diseases. Modern voltammetric and amperometric methods are increasingly used for cholesterol monitoring. Consequently, the problem of electrode fabrication for cholesterol detection has high importance for clinical tests. Novel electrode materials initiated the fast growth of electrochemical biosensors. Biomaterials are still the most frequently used modifiers for cholesterol sensors due to their high selectivity. However, biomaterials have low stability complicating their practical applications. This fact is crucial for analytical parameters such as limit of detection (LOD) and sensitivity. Therefore, nanomaterials are used to eliminate disadvantages of biomaterials and to improve sensors performance by increasing the electrode surface, conductivity and sensitivity. This review is focused on the use of non-enzymatic electrodes for cholesterol quantification and on different approaches to their fabrication. Firstly, the necessity and role of modifier is discussed. Afterwards, the advantages and disadvantages of currently used modifiers are critically compared together with all aspects and approaches to sensors fabrication. Finally, the prospects of non-enzymatic electrodes application for cholesterol sensors engineering are summarised.

• MeSH
• biosenzitivní techniky * MeSH
• cholesterol MeSH
• diabetes mellitus 2. typu * MeSH
• elektrochemické techniky MeSH
• elektrody MeSH
• lidé MeSH
• limita detekce 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

The method for assessing the level of nitric oxide (II) (NO) by voltammetric monitoring of nitrite ions was carried out on models M1 and M2 of polarized macrophages induced from monocytes of human peripheral blood with the addition of lipopolysaccharide (LPS) and interleukin-4 (IL-4), respectively. The model of induction of M1 and M2 macrophages was used in the work to achieve the corresponding shifts in the functional status of studied cells. Ethyl nitrite (EtONO) was used as a standard compound of nitrite ions for electrochemical measurements. Electrochemical determination of nitrite ions was performed by anodic linear sweep voltammetry in the first-order derivative mode (ALSV FOD) in Britton-Robinson (BR) buffer with pH 4.02 on carbon ink modified graphite electrode. EtONO calibrations were linear over a concentration range from 2 to 9 μmol L-1 with corresponding regression equation y = 0.768c - 0.048. Limit of detection (LOD) (S/N = 3) was 0.38 μmol L-1. The results of the study showed the fundamental possibility of using voltammetry to assess indirectly the production of nitric oxide by cells in supernatants of the monocytic macrophage lineage. The level of nitric oxide metabolites (nitrite ions) in supernatants was associated with the functional state of macrophages.

• MeSH
• dospělí MeSH
• dusitany krev   MeSH
• elektrochemické techniky metody   MeSH
• imunofenotypizace MeSH
• kultivační média MeSH
• lidé středního věku MeSH
• lidé MeSH
• limita detekce MeSH
• makrofágy cytologie   imunologie   metabolismus   MeSH
• mladý dospělý MeSH
• polarita buněk MeSH
• průtoková cytometrie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý 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.

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

The treatment of some inborn metabolism errors requires cholesterol substitution therapy. Cholesterol plays a vital role in the human body. Therefore, the majority of cholesterol determination techniques are targeted to blood and blood serum. Nevertheless, cholesterol determination in food is important as well. In this paper, cholesterol determination using differential pulse voltammetry (DPV) in dairy products (e.g., milk, clotted cream, yogurt, butter, etc.) is reported with a novel nonenzymatic sensor based on diphosphonic acid of 1,4-diacetylglycoluril (DPADGU) as an electrode surface modifier. Stable anodic response was obtained from cholesterol on the modified carbon-based electrode. The sensor has high stability, sensitivity (20 μA mol L-1 cm-2), and a wide linear range from 1 up to 200 μM. The LOD and LOQ values are 1.5 and 5.1 μM, respectively. The developed methods were successfully applied to the above mentioned dairy products. Graphical abstract ᅟ.

• MeSH
• analýza potravin přístrojové vybavení   MeSH
• biosenzitivní techniky MeSH
• cholesterol analýza   normy   MeSH
• elektrochemické techniky přístrojové vybavení   MeSH
• kalibrace MeSH
• katalýza MeSH
• koncentrace vodíkových iontů MeSH
• referenční standardy MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• Publikační typ
• časopisecké články MeSH