Oxidative Stress Markers and Histopathological Changes in Selected Organs of Mice Infected with Murine Norovirus 1 (MNV-1).

This paper describes the effects of murine norovirus (MNV) infection on oxidative stress and histopathological changes in mice. This study uses histopathological assays, enzymatic and non-enzymatic antioxidant markers, and total oxidative status and capacity (TOS, TAC). The results suggest that MNV infection can lead to significant changes with respect to the above-mentioned parameters in various organs. Specifically, reduced superoxide dismutase (SOD), Mn superoxide dismutase (MnSOD), catalase (CAT), and glutathione reductase (GR) activities were observed in liver tissues, while higher MnSOD activity was observed in kidney tissues of MNV-infected mice when compared to the control. GR activity was lower in all tissues of MNV-infected mice tested, with the exception of lung tissue. This study also showed that norovirus infection led to increased TOS levels in the brain and liver and TAC levels in the brain, while TOS levels were significantly reduced in the kidneys. These changes may be due to the production of reactive oxygen species (ROS) caused by the viral infection. ROS can damage cells and contribute to oxidative stress. These studies help us to understand the pathogenesis of MNV infection and its potential effects on oxidative stress and histopathological changes in mice, and pave the way for further studies of the long-term effects of MNV infection.

Sensitive electrochemical gold nanoparticle-based immunosensor for norovirus detection in food samples.

Norovirus (NoV) infection is one of the most common non-bacterial causes of gastroenteritis among the population worldwide. From the point of view of medical diagnostics, it is important to develop a system that would sensitively and selectively detect norovirus from a patient's sample in order to control and limit its spread. In this paper, we present a stable and sensitive NoV (mouse model) detection matrix in infected food samples. The bio-platform was made of a modified gold electrode with a self-assembled l-cysteine monolayer, covered with gold nanoparticles, a linker and an antibody specific to the VP1 surface protein of the virus. Binding of the VP1 protein to the antibody caused a decrease in the current strength confirmed by electrochemical techniques - cyclic voltammetry (CV) and differential pulse voltammetry. The reduction of the current was proportional to the concentration of NoV sample. The biosensors showed high sensitivity and linearity in a range from 1 × 10-9 to 1 × 10-18 TCID50, with the detection limit of 1 × 10-18 TCID50. CV showed a diffusion-controlled process. In addition, each modification step was confirmed by scanning electron microscopy, electrochemical impedance spectroscopy, and CV. The described immunosensor showed excellent recovery values, good linearity and long-term stability, crucial parameters for biosensor construction.

A Novel Strategy for Selective Thyroid Hormone Determination Based on an Electrochemical Biosensor with Graphene Nanocomposite.

This article presents a novel and selective electrochemical bioassay with antibody and laccase for the determination of free thyroid hormone (free triiodothyronine, fT3). The biosensor was based on a glassy carbon electrode modified with a Fe3O4@graphene nanocomposite with semiconducting properties, an antibody (anti-PDIA3) with high affinity for fT3, and laccase, which was responsible for catalyzing the redox reaction of fT3. The electrode modification procedure was investigated using a cyclic voltammetry technique, based on the response of the peak current after modifications. All characteristic working parameters of the developed biosensor were analyzed using differential pulse voltammetry. Obtained experimental results showed that the biosensor revealed a sensitive response to fT3 in a concentration range of 10-200 µM, a detection limit equal to 27 nM, and a limit of quantification equal to 45.9 nM. Additionally, the constructed biosensor was selective towards fT3, even in the presence of interference substances: ascorbic acid, tyrosine, and levothyroxine, and was applied for the analysis of fT3 in synthetic serum samples with excellent recovery results. The designed biosensor also exhibited good stability and can find application in future medical diagnostics.

An Ultrasensitive Biosensor for Detection of Femtogram Levels of the Cancer Antigen AGR2 Using Monoclonal Antibody Modified Screen-Printed Gold Electrodes.

The detection of cancer antigens is a major aim of cancer research in order to develop better patient management through early disease detection. Many cancers including prostate, lung, and ovarian secrete a protein disulfide isomerase protein named AGR2 that has been previously detected in urine and plasma using mass spectrometry. Here we determine whether a previously developed monoclonal antibody targeting AGR2 can be adapted from an indirect two-site ELISA format into a direct detector using solid-phase printed gold electrodes. The screen-printed gold electrode was surface functionalized with the anti-AGR2 specific monoclonal antibody. The interaction of the recombinant AGR2 protein and the anti-AGR2 monoclonal antibody functionalized electrode changed its electrochemical impedance spectra. Nyquist diagrams were obtained after incubation in an increasing concentration of purified AGR2 protein with a range of concentrations from 0.01 fg/mL to 10 fg/mL. In addition, detection of the AGR2 antigen can be achieved from cell lysates in medium or artificial buffer. These data highlight the utility of an AGR2-specific monoclonal antibody that can be functionalized onto a gold printed electrode for a one-step capture and quantitation of the target antigen. These platforms have the potential for supporting methodologies using more complex bodily fluids including plasma and urine for improved cancer diagnostics.

Electrochemical Immunosensors Based on Screen-Printed Gold and Glassy Carbon Electrodes: Comparison of Performance for Respiratory Syncytial Virus Detection.

This paper presents the development and comparison of label-free electrochemical immunosensors based on screen-printed gold and glassy carbon (GC) disc electrodes for efficient and rapid detection of respiratory syncytial virus (RSV). Briefly, the antibody specific to the F protein of RSV was successfully immobilized on modified electrodes. Antibody coupling on the Au surface was conducted via 4-aminothiophenol (4-ATP) and glutaraldehyde (GA). The GC surface was modified with poly-L-lysine (PLL) for direct anti-RSV conjugation after EDC/NHS (1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-Hydroxysuccinimide) activation. Electrochemical characterizations of the immunosensors were carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). GC-based immunosensors show a dynamic range of antigen detection from 1.0 × 105 PFU/mL to 1.5×107 PFU/mL, more than 1.0 × 105 PFU/mL to 1.0 × 107 PFU/mL for the Au-based sensor. However, the GC platform is less sensitive and shows a higher detection limit (LOD) for RSV. The limit of detection of the Au immunosensor is 1.1 × 103 PFU/mL, three orders of magnitude lower than 2.85 × 106 PFU/mL for GC. Thus, the Au-based immunosensor has better analytical performance for virus detection than a carbon-based platform due to high sensitivity and very low RSV detection, obtained with good reproducibility.

Antibody Modified Gold Electrode as an Impedimetric Biosensor for the Detection of Streptococcus pyogenes.

Streptococcus pyogenes is a known cause of a wide spectrum of diseases, from mild and acute to severe invasive infections. This paper concerns the development of a novel impedimetric biosensor for the detection of the mentioned human pathogen. The proposed biosensor is a gold disk electrode modified with commercially available antibodies attached to the surface of the electrode by carbodiimide chemistry. The conducted tests confirmed the specificity of the antibodies used, which was also demonstrated by the results obtained during the detection of S. pyogenes using electrochemical impedance spectroscopy. The developed sensor successfully detected the presence of S. pyogenes in the sample and the detection limit was calculated as 9.3 cfu/mL. The results obtained show a wide linear range for verified concentrations of this pathogen in a sample from 4.2 × 102 to 4.2 × 106 cfu/mL. Furthermore, the optimal experimentally determined time required to perform pathogen detection in the sample was estimated as 3 min, and the test did not lead to the degradation of the sample.

Tumor-specific hyperthermia with aptamer-tagged superparamagnetic nanoparticles.

Targeted therapy is a method owing to its limited side effect profile, particularly in cancer treatment. Magnetic hyperthermia, which is induced by nanoparticles (NPs) conjugated with targeting agents, can be useful in combination with chemo- or radiotherapy. In this paper, we constructed dextran-coated ferric oxide NPs conjugated with specific anti-human epidermal growth factor receptor (HER2) aptamer and used them to induce magnetic hyperthermia in cultured cells. The specificity of the tagged NPs was determined by studying their effect relative to that of non-tagged NPs against two cell lines: human adenocarcinoma SK-BR3, overexpressing the HER2 receptor; and U-87 MG, a human glioblastoma epithelial cell line, not expressing HER2. In order to confirm the interaction of the tagged NPs with the cells we used, fluorescence microscopy and fluorescence-activated cell sorting analysis were performed. All of these experiments showed that the aptamer-tagged NPs were highly specific toward the HER2-expressing cells. In addition, a ninetyfold lower dose of the tagged NPs relative to that of the non-tagged NPs was needed to achieve ~50% cell killing by hyperthermia of the SK-BR3 cell line, while for the U-87 MG cells the viability level was close to 100%. These results show that targeted NPs can be applied at substantially lower doses than non-targeted ones to achieve similar effects of hyperthermia, which should greatly limit the side effects of treatment.

FGF1-gold nanoparticle conjugates targeting FGFR efficiently decrease cell viability upon NIR irradiation.

Fibroblast growth factor receptors (FGFRs) are overexpressed in a wide variety of tumors, such as breast, bladder, and prostate cancer, and therefore they are attractive targets for different types of anticancer therapies. In this study, we designed, constructed, and characterized FGFR-targeted gold nanoconjugates suitable for infrared-induced thermal ablation (localized heating leading to cancer cell death) based on gold nanoparticles (AuNPs). We showed that a recombinant ligand of all FGFRs, human fibroblast growth factor 1 (FGF1), can be used as an agent targeting covalently bound AuNPs to cancer cells overexpressing FGFRs. To assure thermal stability, protease resistance, and prolonged half-life of the targeting protein, we employed highly stable FGF1 variant that retains the biological activities of the wild type FGF1. Novel FGF1 variant, AuNP conjugates are specifically internalized only by the cells expressing FGFRs, and they significantly reduce their viability after irradiation with near-infrared light (down to 40% of control cell viability), whereas the proliferation potential of cells lacking FGFRs is not affected. These results demonstrate the feasibility of FGF1-coated AuNPs for targeted cancer therapy.