Zbynek Heger

Nanoscale virus biosensors: state of the art

License. The full terms of the License are available at http://creativecommons.org/licenses/by-nc/3.0/. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. Permissions beyond the scope of the License are administered by Dove Medical Press Limited. Information on how to request permission may be found at: http://www.dovepress.com/permissions.php Nanobiosensors in Disease Diagnosis 2015:4 47–66 Nanobiosensors in Disease Diagnosis Dovepress

Antiviral activity of fullerene C60 nanocrystals modified with derivatives of anionic antimicrobial peptide maximin H5

Many active antiviral substances come from natural sources. In this way, peptides, isolated from Asian toad Bombina maxima, called maximins, are very promising. Most of them have good antimicrobial activity; however, derivatives of anionic 20 amino acids-long maximin H5 show also promising antiviral activity. The effect can be enhanced by binding to suitable nanocarriers such as fullerenes. In the present study, six mutants of maximin H5 were designed where aspartic acid at position 11 was replaced by asparagine, histidine, tyrosine, alanine, glycine, or valine. The binding yield of each peptide to fullerene C60 nanocrystals was studied by derivatization with fluorescent reagent fluorescamine. The antiviral activity of these peptides and peptides bound to fullerene C60 nanocrystals was studied using bacteriophage λ as a model virus. All of the designed peptides had higher antiviral activity compared to maximin H5. The highest antiviral activity was observed in case of maximin variants H5N, H5V, or H5Y. Moreover, the antiviral activity was dependent on the amount of peptide bound on the surface of fullerene C60 nanocrystals, which was enhanced by trimesic acid (benzene-1,3,5-tricarboxylic acid) treated fullerene C60 nanocrystals.Graphical abstract

Influence of microbiome species in hard-to-heal wounds on disease severity and treatment duration

BACKGROUNDnInfections, mostly those associated with colonization of wound by different pathogenic microorganisms, are one of the most serious health complications during a medical treatment. Therefore, this study is focused on the isolation, characterization, and identification of microorganisms prevalent in superficial wounds of patients (n=50) presenting with bacterial infection.nnnMETHODSnAfter successful cultivation, bacteria were processed and analyzed. Initially the identification of the strains was performed through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry based on comparison of protein profiles (2-30kDa) with database. Subsequently, bacterial strains from infected wounds were identified by both matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and sequencing of 16S rRNA gene 108.nnnRESULTSnThe most prevalent species was Staphylococcus aureus (70%), and out of those 11% turned out to be methicillin-resistant (mecA positive). Identified strains were compared with patients diagnoses using the method of artificial neuronal network to assess the association between severity of infection and wound microbiome species composition. Artificial neuronal network was subsequently used to predict patients prognosis (n=9) with 85% success.nnnCONCLUSIONSnIn all of 50 patients tested bacterial infections were identified. Based on the proposed artificial neuronal network we were able to predict the severity of the infection and length of the treatment.

3D printed stratospheric probe as a platform for determination of DNA damage based on carbon quantum dots/DNA complex fluorescence increase

We present a utilization of carbon quantum dots (CQDs), passivated with polyethylene glycol as a fluorescent recognition probe for DNA damage. Synthesized CQDs were characterized in detail, using optical and electrochemical methods. Further, fluorescent behavior of CQDs was monitored in the presence of genomic DNA, isolated from Staphylococcus aureus. In laboratory conditions, after 30xa0min of exposure to UV irradiation (λxa0=xa0254xa0nm), the DNA/CQDs complex significantly increased its fluorescence. Further, stratospheric probe was suggested and crafted by using technology of 3D printing (acrylonitrile–butadiene–styrene as a material). CQDs were exploited to evaluate the DNA damage in stratospheric conditions (up to 20,000xa0m) by determination of fluorescence increase (λexcxa0=xa0245xa0nm, λemxa0=xa0400xa0nm), together with other parameters (temperature, humidity, altitude, pressure, UV intensity, and X-ray irradiation). The obtained data showed that the sensor utilizing the DNA/CQDs was able to identify the DNA damage, together with external conditions. It was shown the proposed concept is able to operate at temperatures lower than −70xa0°C. The proposed protocol may by applicable as a biosensor for long-term space missions, like international space station, missions to the Moon or Mars.Graphical abstract

Zinc and zinc-containing biomolecules in childhood brain tumors

Zinc ions are essential cofactors of a wide range of enzymes, transcription factors, and other regulatory proteins. Moreover, zinc is also involved in cellular signaling and enzymes inhibition. Zinc dysregulation, deficiency, over-supply, and imbalance in zinc ion transporters regulation are connected with various diseases including cancer. A zinc ion pool is maintained by two types of proteins: (i) zinc-binding proteins, which act as a buffer and intracellular donors of zinc and (ii) zinc transporters responsible for zinc fluxes into/from cells and organelles. The decreased serum zinc ion levels have been identified in patients suffering from various cancer diseases, including head and neck tumors and breast, prostate, liver, and lung cancer. On the contrary, increased zinc ion levels have been found in breast cancer and other malignant tissues. Zinc metalloproteomes of a majority of tumors including brain ones are still not yet fully understood. Current knowledge show that zinc ion levels and detection of certain zinc-containing proteins may be utilized for diagnostic and prognostic purposes. In addition, these proteins can also be promising therapeutic targets. The aim of the present work is an overview of the importance of zinc ions, zinc transporters, and zinc-containing proteins in brain tumors, which are, after leukemia, the second most common type of childhood cancer and the second leading cause of death in children after accidents.

Effect of HPV on tumor expression levels of the most commonly used markers in HNSCC

Approximately 90xa0% of head and neck cancers are squamous cell carcinomas (HNSCC), and the overall 5-year survival rate is not higher than 50xa0%. There is much evidence that human papillomavirus (HPV) infection may influence the expression of commonly studied HNSCC markers. Our study was focused on the possible HPV-specificity of molecular markers that could be key players in important steps of cancerogenesis (MKI67, EGF, EGFR, BCL-2, BAX, FOS, JUN, TP53, MT1A, MT2A, VEGFA, FLT1, MMP2, MMP9, and POU5F). qRT-PCR analysis of these selected genes was performed on 74 biopsy samples of tumors from patients with histologically verified HNSCC (22 HPV–, 52 HPV+). Kaplan-Meier analysis was done to determine the relevance of these selected markers for HNSCC prognosis. In conclusion, our study confirms the impact of HPV infection on commonly studied HNSCC markers MT2A, MMP9, FLT1, VEGFA, and POU5F that were more highly expressed in HPV-negative HNSCC patients and also shows the relevance of studied markers in HPV-positive and HPV-negative HNSCC patients.

Use of green fluorescent proteins for in vitro biosensing

Due to the considerable stability of green fluorescent proteins and their capacity to be readily permutated or mutated, they may be exploited in multiple ways to enhance the functionality of in vitro biosensors. Many possibilities, such as the formation of chimeras with other proteins or antibodies, as well as Förster resonance emission transfer performance, may be used for the highly sensitive and specific detection of the target molecules. This review considers the great potential of green fluorescent proteins as the fluorescent probing or recognition biomolecule in various in vitro biosensors applications, as well as obstacles associated with their use.