Seznam abstraktů 2019: POSTEROVÁ SEKCE C

Selective tissue visualization and localized tumor regression without affecting the surrounding healthy tissues is a critical concern in cancer nanomedicine. Importantly, the complete wrapping of flimsy matrix like liposome by multifunctional graphene oxide is an interesting engineering for nanomedicine design. Moreover, designing a safe and biodegradable nanohybrid with significant theranostic ability is in current need for targeted combined therapies. Here, we report a comprehensive results of in vivo tumor diagnosis and phototriggered tumor regression using a biodegradable red emissive nanotheranostic system viz., Graphene Oxide Flakes fortified Liposome (GOF-Lipo), functionalized with Folic Acid (FA); GOF-Lipo-FA. Graphene oxide support enhances the stability of drug loaded liposomes in extracellular environment that prevent the premature release of loaded anticancer drug from liposomal cavity. Promising outcomes of tumor regression (~ 300 to 25 mm3) from organized cellular and animal studies are demonstrated in this work. These studies reveal superior biocompatibility, deep intracellular localization, 4T1 breast tumor diagnosis and long time tumor binding ability of injected emissive nanohybrid. Overall, a single dose of designed multifunctional system demonstrates best tumor regression.

Because of the strong absorption in the visible and near-infrared spectral region, Ag2S nanoparticles (NPs) can act as sensitizers of local photohyperthermia (PHT) to destroy tumors and cancer cells without affecting the surrounding normal tissue.
The aim of our work was to create stable Ag2S NPs with strong optical absorption of the visible slight and temperature-dependent photoluminescence (PL) in the near-IR (800-1200 nm) spectral region.
Samples of Ag2S NPs were prepared by using wet chemical synthesis with two precursors - silver sulfide (AgNO3) and thiourea (TIU). The size and morphology of the prepared NPs were studied by means of the scanning electron microscopy (SEM) and X-ray diffraction technique. The element composition of Ag2S NPs was determined by X-ray fluorescence analysis Raman spectroscopy and PL measurements were carried out by using a micro-Raman.
The results obtained allow us to draw the following conclusions: 1)Ag2S NPs with average size below 50 nm could be obtained.; 2)The prepared NPs absorb strongly light in the visible spectral region.; 3)The PL spectra of Ag2S NPs reveal peaks in the spectral region from 800 to 1050 nm.
The obtained results indicate that Ag2S NPs with desired structural and optical properties can be prepared by using the wet chemistry rout.

Raman spectroscopy (Raman) is an effective method of chemical analysis, studying the composition and structure of substances. It is known that the presence of plasmon particles near the object of study makes it possible to amplify the Raman signal. Noble metal nanoparticles (NPs) and their alloys are an attractive object of study due to their unique physicochemical and plasmonic properties. Various sensors and sensors have already been implemented on the basis of arrays of Au, Ag, and Cu nanoparticles, however, the effect of the giant Raman scattering observed on such structures, which makes it possible to amplify the Raman signal by at least 1 000 000 times, is of the greatest interest. The creation of the SERS structures is based on this effect of giant Raman scattering of light. The effect of giant Raman scattering can be used to detect substances of low concentration, which is promising for the diagnosis and prevention of serious diseases in the early stages. In this work, the optimization of the SERS structure will be shown and the possibility of detecting substances of low concentration, in particular trimethylamine N-oxide (TMAO), will be demonstrated. Exceeding threshold levels of TMAO is a precursor to a number of diseases leading to disability and death. Monitoring and normalizing its level in the body is one of the important stages of preventive medicine.

We developed a transdermal drug delivery system containing tetracycline as a model antibiotic for wound healing application. Our previous in vitro tests proved no cytotoxic effect nor antibacterial activity of the silica nanofiber based matrix. This study was designed to evaluate biocompatibility of our nanofiber-antibiotic system via reconstructed human skin model, and to confirm sustained release of the incorporated active compound. Further characterization showed that both moisture vapor permeability and enhanced hydrophilicity of the modified nanofibers remained consistent after functionalization. The summarized results proved that this drug delivery system is a perspective solution in potential medicated sustained release patch for wound healing.

This work demonstrates the preparation and characterization of size-controlled liposomes (LIPs) in the diameter range of 50-250 nm for encapsulation of the fluorescent Rhodamin-B (RhoB) as a model drug molecule. During the experimental work three different encapsulation techniques have been studied and the dominant effect of the size, the structure and the applied encapsulation processes on the binding as well as the dissolution of the model drug have been interpreted. The in vitro examined dissolution of fluorescent dye from the liposomal colloid system was also presented in physiological environment. According to the evaluation of release profiles beside the appropriately chosen size controlling procedure the remote loading encapsulation technique can be increase the half-life of RhoB from 0.8 hours to nearly two hours. Moreover this findings we point out the importance of application way of the chosen kinetic model. The coefficient of determination based choice of the appropriate mathematical model can be completely false if only the linearized forms are applied.

This contribution is focused on the preparation of drug delivery systems by combining stealth liposomes and trimethylchitosan (TMC). TMC is known to provide inhalation administration due to the reversible opening of tight junction in pulmonary alveoli [1]. Through the tight junction, the stealth liposomes could continue into the bloodstream. The suitable size of liposomes could support passive targeting thanks to EPR effect. Addition of polyethyleneglycole to liposomes should provide a reduction of opsonization and allow longer circulation in the bloodstream [2].
In this study, liposomes were prepared from phosphatidylcholine, phosphatidic acid and polyethyleneglycole bound to phosphatidylethanolamine. Experiments were focused to verify interaction between liposomes with negative surface covered by PEG with polycation TMC. The formation of system was checked using dynamic light scattering and electrophoretic light scattering. After the binding of TMC to stealth liposomes, particles size increased from 95 to 187 nm and the zeta potential changed from negative (-15 mV) to positive (34 mV) value. This complex, made up of combination of TMC and stealth liposomes, could be used in the area of inhalation administration. At least this complex could serve as a starting material for a thorough study of its utility.
REFERENCES: [1] MOURYA, V. & INAMDAR, N. Trimethyl chitosan and its applications in drug delivery. Journal of Materials Science: Materials in Medicine. DOI: 10.1007/s10856-008-3659-z.; [2] KRAFT, J. C. et al. Emerging Research and Clinical Development Trends of Liposome and Lipid Nanoparticle Drug Delivery Systems. Journal of Pharmaceutical Sciences. DOI: 10.1002/jps.23773.

An effective alternative for treating cancers can be target transport of drugs to tumor cells. To implement this research, it is necessary to create an universal transport system that will allow to control the process of drug delivery and visualization of in vivo applications. The main objective of the research is to form a fully biocompatible low-toxic system with magnetic luminescent properties. The creation of the specified properties of the system will be carried out by combining the magnetic properties of superparamagnetic iron oxide nanoparticles and the photoluminescent properties of semiconductor quantum dots based on elements of groups I-III-VI (core/shell AgInS2/ZnS and CuInS2/ZnS). The basis for the hybrid system will be calcium carbonate microspheres coated with a shell consisting of a controlled number of differently charged polyelectrolytes layers.
ACKNOWLEDGEMENTS: We thank the Federal Target Program for Research and Development of the Ministry of Education and Science of the Russian Federation, grant no. 14.587.21.0047 (ID RFMEFI58718X0047) for financial support.

Some types of nanoparticles such as gold and silver show interesting chemical properties. Pseudoperoxidase activity has been found in iron- or gold-based materials, but some silver nanoparticles (AgNPs) also exhibit such properties. Pseudoperoxidase activity of AgNPs prepared by green synthesis using sage leaves was studied. The AgNPs (prepared by green synthesis using sage leaves) size ranged from 20 to 50 nm and zeta potential was found to vary from -10 to 20 mV, with absorption maximum being 430 nm. The peroxidase-like activity was monitored in the presence of 5 mM 3,3',5,5'-tetramethylbenzidine (TMB) and hydrogen peroxide (30%). The nanoparticles showed about 80% activity of 1 mU horseradish peroxidase (HRP). In addition, AgNPs were applied to maize seedlings (5 days in hydroponics system) at concentrations of 1 mg/L, 50 mg/L, and 150 mg/L. Peroxidase activity in leaves after 48 hours was 59.5, 67.5, and 57.2 µg.mL-1 of HRP, respectively. Peroxidase activity of untreated plant leaves was 58.8 µg.mL-1 of HRP. Peroxidase activity in roots after 48 hours was 101.6, 109.0, and 156.7 µg.mL-1 of HRP, respectively. The peroxidase activity level of the control variant in root of treatment was 98.7 µg.mL-1 of HRP. The results indicate that the determination of peroxidase activity could be used to assess the phytotoxicity of nanoparticles in plants.

The main objective of this study is to develop a novel material which permits to controlled release the cannabidiol (CBD) and posteriorly the carbon xerogel microspheres removal the aflatoxin. The carbon xerogel microspheres were prepared by sol-gel method, which was used as support for the functionalization with phosphoric acid and melamine. The support and modified materials were characterized by scanning electronic microscopy SEM, N2 adsorption at −196◦C, X-ray photoelectron spectroscopy (XPS) and the pHpzc value. For the loading of the cannabidiol (CBD) in the porous samples at 25 °C, an adsorption experiment in batch - mode varying the concentration of CBD was used. The desorption kinetics was performed at two conditions for simulating the gastric (pH of 2.1) and intestinal (pH of 7.4) conditions at 37 °C based on in-vitro CBD release. Posteriorly, the samples obtained were evaluated as aflatoxin removal, which was evaluated in the adsorption experiment at pH of 7.4 and 37 °C. The adsorption isotherms show a behavior type I-b, being the adsorbed uptake of CBD higher for the support then for the modified materials. Meanwhile, the desorption kinetics of CBD at gastric condition releases values lower of 8 %, the remaining amount until to reach the 100% is obtained at pH of 7.4, based on the in-vitro experiment. The results of aflatoxin were successful, showing a total removal in less of 30 min for all the materials evaluated.

Cerium oxide (CeO2) nanoparticles present an interesting material for various applications in biotechnology and medicine. The mechanism of CeO2 nanoparticles biological activity is supposed to be related to the presence both Ce3+ and Ce4+ ions on the surface of the nanocrystal. We studied and compared the catalytic activity of CeO2 nanoparticles synthesized by chemical and physical methods. The cerium oxide was found to demonstrate catalase-like and peroxidase activity. CeO2 nanoparticles obtained by a chemical method showed more pronounced catalytic properties. In addition, this material catalyzed the decomposition of hydrogen peroxide by the enzyme horseradish peroxidase.

We report the optimal conditions for the separation of spermidine from different types of samples, for example blood or cancer cells and its subsequent determination by ion-exchange liquid chromatography (IEC) with UV-VIS detector. Here in, we synthesized paramagnetic particles able to isolate and immobilize spermidine from blood of patients with cancer or cancer cells and thus preconcentrate it for analysis. Dowex surface was covered by nanomaghemite (γ-Fe2O3) or maghemite particles surface was modified by chitosan and sulfoxyethyl cellulose. The best separation properties showed Dowex microparticles. The paramagnetic particles can be used in the future for isolation of spermidine from real samples and diagnosis of cancer.

This study investigated if a single dose of polyethylene glycol-coated Fe3O4 nanoparticles (IONs) alters gene expression of genes involved in iron homeostasis, including those involved in the acute phase response to inflammation: hepcidin (main systemic regulator of iron metabolism) and ferritin (involved in cellular iron storage) in adult Wistar-Kyoto rats. In addition, the involvement of nuclear factor erythroid 2-related factor 2 (Nrf2, redox homeostasis regulatory factor) mediated mechanism was investigated. IONs (30 nm, hydrodynamic size ~51 nm) were administered i.v. (1 mg Fe/kg in saline) during 10-min infusion and the effects were investigated 90 min post-infusion. Saline was administered to control rats. The presence of IONs in the liver was confirmed by SQUID magnetometry. mRNA expression was investigated by the real-time qRT-PCR. Nitric oxide synthase (NOS) activity was investigated by conversion of 3H-L-arginin. IONs had no effect on NOS activity while inducible iNOS (nos2) mRNA was significantly elevated. Hepcidin (encoded by Hamp), ferritin heavy chain-1 (fth1) and nrf2 mRNAs expression was significantly elevated after IONs application vs. control. No effects of IONs on ferroportin (fpn1), divalent metal transporter-1, transferrin (iron transporting, negative acute phase protein) and transferrin receptor-1 (tfR1) mRNAs were found. In addition, expression of nrf2 mRNA positively correlated with all nos2, fpn1, fth1 and tfR1 mRNAs, respectively. In conclusion, single i.v. administration of IONs induced expression of mRNAs of genes of acute phase proteins (iNOS, hepcidin, ferritin) without changes in other genes involved in iron metabolism in rats. ACKNOWLEDGEMENTS: This study was supported by APVV-16-0263, VEGA-2/0160/17, VEGA-2/164/17 and SAV-BAV-18-11.

Diagnostics play a central role in the early detection and control of outbreaks and can enable a more nuanced understanding of the disease kinetics and risk factors. The Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by a novel coronavirus (Middle East respiratory syndrome coronavirus (MERS‐CoV) that was first identified in Saudi Arabia in 2012. Approximately 35% of reported patients with MERS-CoV infection have died, thus this virus is one of the high-priority pathogens identified by the WHO. Diagnostic testing of this virus is still a major concern in most of diagnostic laboratories. To date the quantitative Real-time Polymerase Chain reaction (qRT-PCR) is the mainstay for diagnosis of MERS-CoV. This technique has many limitations, including a long turnaround time and lack of common measurements and correlations with Viral Load, moreover no FDA-approved/cleared tests that identify the existence of MERS-CoV in clinical specimens are available. In this study we developed a nanoparticle-based technology constituted of a combination of nanoparticle-based immuno-capture of viral particles followed by flow-virometry-based detection. Optimization and proof of concept of our methodology was performed using MERS-CoV mimicking nanoparticles and MERS-CoV pseudo-viruses. We used the new developed technology for MERS-CoV diagnosis in camel and human samples. By comparison to qRT-PCR our methodology showed a comparable sensitivity and specificity with a limit of detection of less than 150 viral particle/ml of specimen.

The radiotherapy is an ever-evolving cancer treatment technique that destroys a tumor with ionizing radiation. The most recent techniques use particles of relatively high mass (protons, carbon, etc.) because of the very precise location of their energy deposition (Bragg peak) and their specific biological effects. These techniques are very promising but require very heavy equipment and still not widespread. The vast majority of treatments are performed, with high-energy photons or electrons. For these particles, very great progress has been made on the delivery of the dose to the tumor and the protection of healthy tissue, thanks to recent irradiation techniques: IMRT (Conformational Radiotherapy with Intensity Modulation) or tomotherapy. The prescription of these treatments requires for their applications an accuracy of 3% of the total dose administered; this requirement leads to the obligation to perform dosimetry checks, in order to verify the compliance of the dose delivered with that prescribed. For this purpose, a certain number of dosimeters are used; such as ionization chambers, dosimetric films or portal imaging to control dose distributions in one of the soft tissues (water, polystyrene, etc.). Nevertheless, these techniques have a number of disadvantages that make their use laborious or long, in a context where time is an important parameter. So, it has become an absolute necessity to look for other materials that meet the demands of radiation therapy. Currently around the world, the most popular materials are plastic or inorganic scintillators. Among these new materials, we have OTC "transparent conductive oxide", among which is zinc oxide (ZnO), studies have shown that it has potential in the field of scintillation and that it allows acquire a simple and rapid dose distribution.
The ZnO crystalline and polycrystalline, has found applications in various fields (industry, electronics or photovoltaic cell), it has an energy gap of 3.3 ev and display a luminescence signal centered on 550 nm, which corresponds to 2, 6 ev.
Very little work has been under taken on the study of its thermoluminescence (TL) properties, when it is subjected to radiation irradiations (β and n). In this study, the ZnO powders were obtained by Sol-Gel chemical treatment using a striker (dihydrated zinc acetate), a solvent (ethanol, methanol, propan-2-ol and DMF), a stabilizer (MEA) and a dopant (Cl Li). All of these elements are dissolved at 30 ° C for 1 hour. Sol solutions of clear and transparent appearances obtained are stored for at least 72 hours.Thin films of ZnO were made from Spin coating on glass substrates and the powders were prepared from SOL solutions. To evaluate the response of ZnO to neutron irradiations. We synthesized ZnO powder doped with lithium (6Li). The ZnO response comes from deposited charges of particles (3H and alpha) resulting from the nuclear reaction of the neutron with lithium 6Li according to the reaction: [6Li (n, α) 3H]. The study of the thermoluminescence properties was carried out starting from 0.25 mm thick pellets made of ZnO powder, they were sintered at 500 ° C-550 ° C-600 ° C-700 ° C-800 ° C and 900 ° C, for 24h in an oven (? Thermolyne 4000) under an atmosphere of air. The pellets were irradiated with a dose rate of 5 Gy / min at room temperature with a Sr / Y90 beta source for a 0.1-20 Gy dose range in a TL / OSL reader (Model / OSL-DA-20 ).
The set of ZnO samples synthesized by Sol-Gel were characterized by; MEB and DRX (Stuctural); EDX, EDXRF and FTIR (chemical composition and stoichiometry); UV-Visible and PL (Optical); and four points (electric). Characterization by TL was performed, with the operating conditions obtained from Mc Keever experiments

Prostate cancer is the most common malignant tumor in men, whose incidence is significantly different geographically and increases with age. For rapid diagnostics, new tumor markers with higher prognostic relevance are still being sought. A very promising candidate molecule is the amino acid sarcosine. The aim of this work was to design a highly sensitive photometric detection system for the sarcosine determination. An original methodology for determining the amino acid sarcosine using Trinder's reaction with sarcosine oxidase and Amplex Red fluorophore has been proposed. To improve the enzymatic reaction sarcosine oxidase and horseradish peroxidase were immobilised on superparamagnetic irone oxide nanoparticles (SPIONs). Absorbance dependence on sarcosine concentration read off at the wavelength of 572 nm was linear over a total range of 0 - 1000 μM (r ≥ 0.99) with limit of detection (LOD) of 2 μM and limit of quantification (LOQ) of 6 μM. The suggested procedure allows to analyze the content of sarcosine in real urine specimens. The proposed method is capable of detecting sarcosine at micromolar concentrations.

In the poster a novel approach of a single nanoparticle binding event detection is presented, allowing detection of gold nanoparticles down to 40 nm diameter. The system is based on a surface plasmon resonance excited on an optical grating combined with a supercontinuum laser and a tuneable filter allowing a use of an optimal spectral region. A large visual field enables a detection of binding events at low concentrations, with a possible application in the field of biochemical analysis.

Photothermal therapy (PTT) is gaining tremendous interest in localized cancer therapy, and gold is one such material which is widely studied. Herein, we report the synthesis of chitosan-g-PNVCL nanoparticles, and the surface decoration with gold nanoshells (Au PNVCL NS), which possessed λmax in near-infrared (NIR) region. The in vitro studies revealed that Au PNVCL NS possesses excellent photothermal transduction potential and biocompatibility. The single dose toxicity testing in small animals revealed no abnormalities, indicated the biocompatibility of Au PNVCL NS. Further, a thorough photothermal efficacy testing in 4T1 xenograft model using 750 nm laser proved the excellent efficacy Au PNVCL NS, prolonging the survival. The fate of Au PNVCL NS was evaluated post PTT at the tumor site as well as in the urine and kidney, and it was observed that a portion of nanoparticles disintegrated. The disintegrated particles were found in urine, kidney and a surge in gold content in urine was observed post PTT.

In this work, composite layers of hexamethyldisilazane (HMDSN) and lactic acid (LA) were prepared using chemical vapor deposition process by a nitrogen atmospheric pressure plasma jet source. The HMDSN vapours were introduced into the plasma jet. Varying LA admixture was added into the jet in the form of aerosol.
The chemical composition, morphology and wettability of resulting films were studied. Infrared spectra and XPS analysis show both Si O like and hydrocarbon structures. With increasing amount of LA admixture, the oxidation of the layers increases. The morphology of the films was measured with SEM. The films prepared with no LA have a foam-like structure. With increasing amount of LA the structure changes into more fractal-like. The X ray diffraction analysis suggests the presence of amorphous SiO2 domains in the films. The films exhibited superhydrophobic properties that can be modified by the post treatment of the samples in DBD discharge.

In this paper, we report the optimal conditions for the isolation and preconcentration of branched chain amino acids (BCAAs) - leucine, valine and arginine from different types of matrix, such as tissue, plasma, blood, bacteria or cells. Herein, we focused on the synthesis of paramagnetic particles able to isolate and immobilize amino acids and thus preconcentrate it for subsequent analysis on ion-exchange liquid chromatography with VIS detector. We modified nanomaghemite (γ-Fe2O3) by multi walled carbon nanotubes (MWCNT) and hyaluronic acid as the functional carriers providing excellent affinity properties. Our paramagnetic particles have potential for better isolation of BCAAs mainly from plasma or bacteria and in the future they can also be applied as a platform of delivery system.

This contribution if focused on formulation of novel ion pair amphiphile (catanionic) system, a colloidal system based on combination of positively and negatively charged surfactants, suitable for interactions with charged biopolymers. Like so more complex double chained phospholipids these systems can form vesicles in aqueous environment and serve like a potential carrier for water soluble as well as water insoluble substances. The zeta potential of these systems can be influenced by adjusting the composition or adding charged amphiphile component to enable formulating a system suitable to interact with selected, oppositely charged, polymer.
For this work we select system suitable for interaction with polyanions. The well-known system is based on combination of hexadecyltrimethylammonium bromide (HTMAB) and sodium dodecylsulfate (SDS) with removed counterions - HTMA-DS ion-pair amphiphile. To this system a double chained positively charged surfactant is usually added to adjust zeta potential value and improved stability of formulated vesicles. We replaced anionic partner with branched analogue of sodium myristyl sulfate and determine size, zeta potential and stability of vesicles prepared from this system compared to standard HTMA-DS formulation.
This work was supported by the Czech Science Foundation, project No. 19-14024J (GACR), and Ministry of Science and Technology, Taiwan, project No. MOST108-2923-E-006-006-MY3.

In this contribution, we present the new approach for plasmon assisted grafting of anisotropic gold nanorods (AuNRs) with spatial selectivity, which was used for creation of nanoparticles with amphiphilic surface. The surface modification was carried out in two stages with implementation of: (I) the plasmon-activated iodonium salt (IS), and (II) the aryl diazonium salt (ADT). The plasmon assisted activation of IS was performed under the illumination of AuNRs with wavelength corresponded to the longitudinal plasmon resonance of AuNRs and resulted in grafting of organic moieties (Ar-(CF3)2) to AuNRs edges. The AuNRs lateral sides remains ungrafted and were further decorated with ADT-COOH. As result of varying substituents in the chemical structures of iodonium and diazonium salts the amphiphilic NPs with spatially divided hydrophobic (grafted to AuNRs edges) and hydrophilic (grafted to AuNRs lateral sides) chemical groups were obtained. Corresponded UV-Vis and Raman measurements confirm the success of AuNRs chemical grafting. As result, the AuNRs with spatially separated chemical moieties were created in very simple way, primarily in solution and without the need of sophisticated technique of NPs mobilization or their surface screening.

This work describes the methodology to produce magnesium oxide and hydroxide nanoparticles by the traditional sol-gel methodology and a new methodology using a nanoprecipitation system previously developed by the Systems Biology Research Group to produce polymeric nanoparticles (Colmenares-Roldan et al. 2018; Colmenares Roldán et al. 2018). The nanoparticles obtained were characterized by TEM, FTIR, and XRD. This paper also shows the evaluation of the nanoparticles developed in the reinforcement of PLGA 85:15 (Resomer LG 857S), were used three levels of nanoparticles and the samples were characterized by AFM to determine the variations in the Young modulus and the hardness using the Oliver-Pharr model. The magnesium hydroxide particles at 1%, 2% and 5% increased the modulus of the material by 37.8%, 26.7% and 14.4% respectively with respect to the non-reinforcing polymer and the magnesium oxide particles at the 1%, 2% and 5% significantly increased the material module by 36.8%, 36.8% and 55.8% respectively. Additionally, biological safety evaluations were carried out on the materials obtained, determining their cytotoxicity, genotoxicity, and mutagenicity to define future biomedical applications.

Apoferritin is nowadays intensively studied mainly for its unique properties and hollow structure. On the one hand apoferritin is a cells-own protein and could be naturally adopted by them. On the other hand empty cavity with 8 nm in diameter could be filled by various metals or chemical composition in nanosize and therefore can figure as nanoreactor. Combination of these two phenomena leads to potential broad field of applications.
Our main goal was to apply filled apoferritin as contrast agent in cryo-electron microscopy (cryo-EM) characterization. In the first step apoferritin was synthetized, isolated, purified and characterized. In the second step apoferritin was mixed with solution of various metal precursors and subsequently metals in excess were removed by gel filtration and metal atoms inside of cavities were reduced by NaBH4. This composite was analyzed by cryo-EM and nature of metal nanoparticles was confirmed by energy-dispersive X-ray spectroscopy.
In the next step filled apoferritin was incubated with cells and its position in cell was located by cryo-EM.
ACKNOWLEDGEMENT: CIISB research infrastructure project LM2015043 funded by MEYS CR is gratefully acknowledged for the financial support of the measurements at the CF Cryo-electron Microscopy and Tomography. This work is financially supported by TA ČR (project TN01000008).

Nowadays, cancer is one of the most outrageous diseases affecting millions of people throughout the world. In this study, the sensitive biosensor for miRNA-21 detection was developed. Through a facile sulfonamide coupling reaction a miRNA-21 specific DNA hybridization probe was immobilized onto a glassy carbon electrode (GCE) modified with electrochemical reduced graphene oxide (erGO). miRNA is a small non coding RNA molecule which plays an important role in gene expression. The level of miRNA in extracellular fluids varying in the presence of cancer and it can serve as potential biomarker for early detection of cancer. An elevated level of miRNA-21 represents a common feature of pathological cell growth or cell stress and is connected with almost all types of cancer and with cardiovascular diseases, as well.
The aim of this study was improve the electrochemical properties by using erGO as a modification for better sensitivity of the developed biosensor. After the modification with erGO, 1-amino-2-naphthol-4-sulfonic acid (AN-SO3-) was electrodeposited on the GCE surface. --Finally, the amino terminated capture probe was immobilized on the GCE via the sulfonamide coupling reaction. The developed biosensor for the detection of specific miRNA sequence was optimized and modified for using in further experiments.

DNA methylation is one of the most studied and basic epigenetic process related to several diseases such as diabetes, neurodegenerative or cardiovascular diseases and even cancer. Methylated DNA presents a new generation of biomarkers which can be used for point-of-care detection. Electrochemical biosensors provide simple, fast, cost-effective, easy-to-use, reliable and efficient detection in contrast with conventional diagnostic methods. These biosensors can be used for early diagnosis of mentioned diseases and increase patient recovery by early clinical interventions. In this study, methylated DNA was detected electrochemically by the developed biosensor. The bare gold electrode was modified by drop-casting reduced graphene oxide with silver nanoparticles which enhance electrochemical signal due to their strong affinity to thiol modified DNA probe via a disulfide bridge. Afterwards, the sensitivity and selectivity of the nanocomposite were examined. The faradic electrochemical impedance spectroscopy was used for determination of the hybridization of the DNA probe with a methylated DNA sequence. The fabricated biosensor shows promising analytical features with a wide detection of the linear range.

A biosensor was developed for monitoring H2O2 based on reduced Graphene Oxide-Cerium Oxide (rGO-CeO2) nanocomposite (NC). The NC shows catalytic effect on the electrochemical reduction of H2O2 at −0.3 V. The effect of the NC on the electrochemical reduction of H2O2 was studied by cyclic voltammetry and compared with bare glassy carbon (GC) and GC/r-GO. Moreover, to improve the signal a complex containing copper was incorporated in the dispersion of the nanocomposite which acts as a mediator. It was found that the electrochemical reduction of H2O2 takes place at less negative potential with increased peak current attitude at GC/r-GO-mediator. The developed sensor GC/r-GO-mediator, was applied for the continuous monitoring of H2O2 by chronoamperometry. The applied potential was −0.3 V which results in the enhanced sensitivity of the developed biosensor. The developed biosensor shows good stability, and reproducibility. The reproducibility of the developed electrode was evaluated by calculation of relative standard deviation value 6.77%. The linear range was found to be 3.4 - 23.48 µg/ml. Furthermore, limit of detection and limit of quantification were 0.68 µg/ml and 2.27 µg/ml respectively.

Generally, the identifications of biomarkers play a key role in the diagnosis of various disorders. However, most of the developed methods require tedious sample preparation, expensive analytical instrumentation. Importantly, they exhibited moderate sensitive, which lacks their use for Point-of-Care (PoC) testing. Further, sensitive, portable, rapid, and low-cost devices are essentially needed for clinical PoC applications. Thus, we report on the use of gold-platinum (Au-Pt) nanohybrids based electrodes as a PoC device for highly sensitive detection of parathyroid hormone (PTH) in human serum samples. The method involves the immobilization of 3-mercaptopropionic acid (3-MPA) into Au surface and subsequent attachment of anti-PTH on the surface of 3-MPA-Au substrate. Serum PTH was detected by monitoring the changes in electrochemical properties (ΔRct and Δi) of the sensor using electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) against a standard hexacyanoferrate (II/III) probe. EIS and DPV electrochemical results revealed that the relative response percentage (RR%) is progressively increased with increasing concentration of PTH in the range of 1 to 100,000 pg. mL−1, with a detection limit of 0.36 pg. mL−1 (EIS) and 0.59, pg. mL−1 (DPV) in serum. Further, to validate the accuracy of the proposed method, PTH was successfully examined in clinical samples (n= 20) by EIS method, exhibiting good agreement with the traditional method/ commercial test.

Cancer is one of the most common causes of death in developing countries and in the developed world. The function of the p53 protein plays an important role in the development of cancer. The protein p53 regulates the expression of genes that are responsible for the control of cell growth, apoptosis or for repair of damaged DNA. It t is encoded by the tumor suppressor gene TP53. If this gene mutates, its product will be damaged. It was found that mutations in the TP53 gene is present in more than 50% of cancer cases. Electrochemical biosensors have proved to be a suitable method for the detection of TP53 and also its mutations. Electrochemical deposition of gold nanoparticles on the surface of working electrode increases the active surface area of the sensor, this leads to a more sensitive detection of the TP53 gene and its mutations. By developing an electrochemical biosensor based on gold nanoparticles modified screen printed electrodes, an efficient platform for detecting the TP53 gene in biological samples is obtained.

Metalloproteins (MTs) are one of the most diverse classes of proteins, with the intrinsic metal atoms providing a catalytic, regulatory and structural role crucial to protein functioning. When stored under aerobic conditions, MTs might form dimers (as well as higher oligomers) that play an essential role as mediators in oxidoreduction signalling pathways. In this work, we explore the non-oxidative dimerization process characterized by metal (Cd) bridging of MT monomers by Förster resonance energy transfer. The formation of MT dimers/oligomers was investigated by applying capillary electrophoresis and matrix-assisted laser desorption/ionization with mass spectrometric detection.

In recent years, scientific research has been associated with diminishment the size of analytical tools with simultaneous improving their characteristics. In this regard, one of the most perspective areas is the microfluidic-based analytical platform. The utilization of microfluidic approach enables the analysis of small volumes of fluids (micro- and nanoliters). In addition, the microfluidic makes it possible to develop a new class of equipment - the so-called complex laboratory (Lab-on-a-chip) devices that allow analyzing complex analytes in various mixtures. In present work, the microfluidic-based micromixer with incorporated AuMs (gold multibranched NPs) nanoparticles with surface grafted oleophilic chemical moieties for detection of pharmaceutics with low solubility in water (ibuprofen has been used as a model compound due to the fact that this is a common pharmaceutics contaminant) was demonstrated. The proposed microfluidic device utilizes the unique advantages of microfluidic, which explores the unusual behavior of liquids limited by microscale and Surface-Enhanced Raman (SERS), capable of recognizing one molecule of the target analyte. The proposed approach is especially relevant in medical diagnostics to determine the drug digestibility and environment monitoring and protection areas.

Virus-induced haemorrhagic fevers often show a rapid, dramatic course. Infectivity and mortality are very high. Such viruses are known to attack primates as well as other animal species. Fast, sensitive, selective diagnostics can be very beneficial for early anti-epidemic measures right in the outbreak. Quantum dots (QDs) have excellent features that make them useful as detection labels. Their use increases the sensitivity of the analytical assay. The use of biologically active components in QDs synthesis brings new properties. Quantum dots are nanocrystals that due to their high stability, ease of preparation and biocompatibility are suitable for labeling biomolecules. CdTe QDs modified with mercaptosuccinic acid (MSA), reduced glutathione (GSH), and plant extracts were prepared. Green synthesized CdTe QDs showed emission depending on the amount of extract applied. Thus, QDs were prepared in full-color scale from blue to red. The modified biomolecules of QDs are applicable for the labeling of nucleic acids. Their long-term stability, including their application onto paper, was tested. CdTe QDs exhibit very good electrochemical detection with the limit of detection (LOD) in nanomolar concentration.

Separating the useful luminescence signal from the nano-agent from the background of the intrinsic biological tissue fluorescence, i.e. autofluorescence, is one of the most serious problems one involved in the development of luminescent biomedical nano-agents will have to face. A new implementation of optical imaging of luminescent carbon multi-functional medical nano-agents in biomaterial using various artificial neural networks (ANN) architectures is proposed as an alternative to classic methods of controlling autofluorescence. In this study, nGO + copolymer PEG-PEI (Cop) + folic acid (FA) nanocomposites and their components were used as the objects of the study. The database consisting of 1459 fluorescence spectra of carbon nanomaterials suspensions with 8 combinations of classes {nGO+Cop+FA}, {nGO+Cop}, {FA}, {nGO+Cop+FA, nGO+Cop}, {nGO+Cop+FA, FA}, {nGO+Cop, FA}, {nGO+Cop+FA, nGO+Cop, FA}, {urine without nanoparticles} was obtained. ANNs of three types - perceptron, wavelet and Kohonen self-organizing maps - were trained and applied to the obtained database. It is demonstrated that this approach allows simultaneous detection of the nanocomposites and their components against the autofluorescence background of human urine with a sufficiently low detection threshold by concentration. The advantages and disadvantages of ANNs application are discussed in the report.
ACKNOWLEDGEMENTS: This study has been performed at the expense of the grant of Russian Science Foundation (project No 17-12-01481) and of the grant of Russian Foundation for Basic Research (project No. 18-32-00779_mol_a).

During the last decades, it was demonstrated that polymerase chain reaction (PCR) is powerful tool of molecular biology to amplified and detect target genes and can be used for various applications such as medicine, agriculture, forensics, archaeology. The recent state-of-the-art in nanotechnology and microfabrication processes employed devices for point-of-care assays which utilize detecting of nucleic acids from ultra-low volume of sample and inexpensive screening at low cost. We demonstrate a new concept of real-time PCR and digital PCR (dPCR) in one device. For droplet real-time detection, the amplification is conducted in 0.3 µL master mixture droplet containing target gene encapsulated with 2 µL of mineral oil. For digital detection was developed chip-based system with microwell sample dispersion. The 3 µL of master mix solution with DNA is pipetted on the silicone chip and covered with a hydrophobically treated glass. We introducing the device which has the experimental setup for droplet PCR and dPCR the same, except for the detectors. This makes the system more economical with use of recyclable microchip, less consumption of components, lower detection time and potential affordable for the point-of-care applications.

The functional plasmon active surfaces was designed and constructed for advanced Raman spectroscopy purposes. There is a huge demand in biochemistry and medicine for on-line observation of microorganism’s behavior, including the biofilms formation. For this goal the Raman spectroscopy measurements can be used. The obstacle we face is that the (bio)liquid may contain a lot of different sized biomolecules. To cut-off unnecessary molecules we propose the utilization of molecular sieve - mesoporous silica thin film (MSTF) deposited on plasmon active surface (periodical gold grating). Our biosensors detect trace amounts of cytotoxic ions and molecules, released from biomaterials. The plasmonic surface was functionalized with MSTF with the aim to provide the selective interaction/entrapping of the targeted objects of interest. Proposed approach also allows to directly monitor cell behavior on the variously modified surfaces and, moreover, surfaces with different morphologies. Development of proposed ideas and concepts introduces an innovative approach in the analysis of complex (bio)molecules system, get new information about the microorganism behavior as well as shed light on previously unknown phenomena in the microbiology field.

Statement of the Problem: Thyroxine (3,5,3’,5′-tetraiodothyronine) or T4 is a crucial hormone produced and released by thyroid gland. It plays a vital role in different body functions like as normal growth and cell differentiation, protein synthesis, carbohydrate metabolism and alteration of body sensitivity to other hormones. It is well-known that unbalanced concentration of T4 leads to serious metabolic disorders (i.e. hyperthyroidism and hypothyroidism). Hence, detection of T4 is clinically important to diagnose metabolic diseases. Although various methods have been developed for analysis of T4, most of them suffer from high cost and require complicated pretreatment. In this regard, electrochemical biosensing systems offer a simple, fast, and high sensitive alternative for detection of T4. Methodology & Theoretical Orientation: In the present study a nanomaterial-based electrochemical aptasensing platform (NEAP) was introduced for highly sensitive, selective and rapid detection of T4. To construct the aptasensor, MoS2 nano-sheets casted onto the surface of screen-printed carbon electrode. Then, this electrode was applied for electrodeposition of gold nanostructures. Afterward, anti-T4 RNA aptamer was immobilized onto the gold nanostructured electrode via thiol chemistry, and another terminus of the aptamer was labeled with ferrocene (Fc) as a redox probe. Upon the specific interaction between T4 and its aptamer, the configuration of aptamer is changed. Conformational changes lead to a change in electron transfer efficiency between Fc conjugated to immobilized aptamer and electron surface. This phenomenon enables signal calibration versus T4 concentration. Conclusion & Significance: The presented electrochemical aptasensor quickly responded to T4 within few minutes. The aptasensor delivered a wide linear dynamic range over 7×10-12 to 1×10-6 M, with a limit of detection 4×10-13 M. Moreover, the ability of the developed aptasensing system was evaluated in human plasma samples in the presence of interferences. The sensor specifically responded to T4 and no structurally related interference was detected. The availability of nanomaterials with superior properties and the ease of its application in biosensing system makes electrochemical biosensor a promising alternative to troublesome assays in clinical application.

Electrospun polycaprolactone nanofibrous mats were used as substrates for the immobilization of biomolecules with the aim to improve cell proliferation on the mats and prepare efficient material for tissue engineering. Additionally, immobilization of antibiotics was tested to obtain antimicrobial properties. Thin films of plasma polymers with amine or carboxyl functional groups prepared by plasma enhanced chemical vapor deposition on the electrospun mats proved to be a reliable platform for the immobilization.

This work studies the properties of modified biopolymers for potential use in targeted drug delivery. Various samples of hydrophobically modified hyaluronan with different degree of substitution were selected. The critical aggregation concentration (CAC) of these samples was measured using fluorescence spectroscopy, wherein it was found that micelle formation occurs over a wide concentration region. Environment of 0.15 M NaCl causes the decrease of CAC only slightly or not at all. The results were confirmed by measuring the dynamic light scattering, which also showed an increase in the size of aggregates with an increasing concentration. One of the samples exhibited a double size distribution. Zeta potential measurements provide information about stability of the samples. The results of this study confirm that the studied samples seem to be a suitable candidates for the post of drug carrier for targeted delivery.

The work was focused on preparing and optimising the preparation of nanofibrous and non-fibrous wound dressings from materials containing bioactive components and testing interaction of prepared materials with human cells. Nanofibrous dressings were based on poly(3-hydroxybutyrate) and non-fibrous dressings were made from alginate and chitosan. Both types of dressings were functionalized by selected antimicrobial drugs, proteolytic enzymes and extracts of plant species. Prepared wound dressings were tested for their cytotoxicity effect, antimicrobial and antioxidant activity.
Prepared materials were characterized by spectrophotometric methods. Determination of antioxidant activity, content of phenolics components, short-term and long-term stability and proteolytic activity were specified. PHB nanofibers were prepared by two techniques, electrospinning and forcespinning. For detailed characterization of nanofibers were used FLIM and FTIR-ATR methods. The wound dressings were tested for determination of antimicrobial effect against selected strains of Gram negative (Serratia marcescens, Escherichia coli) and Gram positive (Micrococcus luteus, Staphylococcus epidermidis) bacteria. The results showed high antioxidant and potentially good antimicrobial effect of tested functionalized dressings.
For potential application in medicine successfully prepared functionalized dressings with antioxidant and antimicrobial effect were tested for safety on human cells. Determination of cytotoxicity was performed by MTT assay using human keratinocytes (HaCat). The results showed no cytotoxicity effect, therefore prepared materials are promising for medical applications. For example, as a skin wound dressing for opened and closed wounds. Another possible application can be in cosmetics. Functionalized materials with antioxidant activity are suitable as a component of anti-aging face masks.

The aim of this work is the development of highly functionalized nanofiber material for wound dressing. A precondition for successful chronic wounds treatment is to reduce contamination by microorganisms. The main idea is to prepare the wound cover for topical application and to release the drug sufficiently long. Prevent frequent rewinding and other material consumption. The cover combines the properties of the barrier against contamination, the carrier of active therapeutic substance with gradual release also the breathable nanofibrous biocompatible material. The dressing material consists of a nanofibrous layer made by electrospinning. The surface of the nanofibrous is covered with an active substance (e.g. antibiotics) enclosed in liposomes or solid lipid microparticles which provide a gradual release at 37 ° C. The thus produced dressing material is tested and verified by scanning electron microscopy (SEM), dynamic light scattering (DLS), release kinetics, antimicrobial tests and cytotoxicity assays.

The polycaprolactone (PCL) nanofiber and collagen were used to design planar scaffold. The scaffold in the form of 2x2 cm was tested on dermal wound of rat. The scaffold was tested in three variants: (a) pure scaffold, (b) after addition of stromal cells to the underside of planar gel structure, (c) or with addition of stromal cells and stimulation by electromagnetic pulses 90 min per day. The collagen gel structure on the nanofiber was upgraded by original carbon quantum dots(CQDs). The quantum dots were prepared in the form of 5 nm red fluorescence particles, the application of particles to the collagen solution (before plymerysation) were tested for variant 150-500 ug/ml. The QCD did not diffuse inside the cells. The main aim of the QCD addition was highlighting of collagen layer for tomographic and histological analysis in different time after application to the wound.
Results of tests show high biocompatibility of PCL nanofiber on dermis. The hisotogical evaluation show variant (c) as the best variant for wound closure. Collagen layer on underside nanofiber was stable for 48h. Analysis of QCD stability in collagen and also no toxicity to surrounding tissue and healing approve very good biocompatibility of this nanoparticles for future in vivo use.
Supported by FV20422 „Development of nanofibrous scaffolds ensuring application of cellular products, including physical stimulation effect, with the intended purpose of the treatment of chronic wounds“, project support provider is Ministry of Industry and Trade Czech Republic.

Contaminated wounds management have been a hot topic over last decade in the material research and many approaches have been evaluated. Applications of nanomaterial-based wound dressings have been tested and most of the tested approaches - including doped nanofibres and antimicrobial nanoparticles have approved their applicability, yet with certain limitations. In case of nanoparticles, their applicability in the wound site can be limited by their instability, as the unbounded nanoparticles can be washed away or form clusters with decreased antibacterial activity in presence of wound exudate and bacterial metabolism products. In the case of nanofibres with antibacterial compounds, the limitations are possible low availability of the compound leading to final concentration bellow the MIC value in the wound site. Some of these limitations may be overcome be combining both these approaches. In this study we present up to date results of the development and evaluation of silver nanoparticles (AgNPs) doped inorganic silica-based nanofibres. We studied impact of the AgNPs concentration and post-treatment of the nanofibres on their morphology, the antibacterial activity and biocompatibility as critical assumptions for their application in wound healing.
ACKNOWLEDGEMENTS: This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic and the European Union - European Structural and Investment Funds in the frames of Operational Programme Research, Development and Education - project Hybrid Materials for Hierarchical Structures (HyHi, Reg. No. CZ.02.1.01/0.0/0.0/16_019/0000843).

Surface-enhanced Raman spectrometry (SERS) represents a powerful method for analysis of a broad spectrum of analytes ranging from inorganic ions to biomolecules of high complexity. It combines the potential of Raman spectrometry for a definite identification of an analyte with remarkable sensitivity achieved by the surface enhancement effect occurring on metal nanoparticles. While low ionic strength influences positively the sensitivity of the SERS measurement, a higher level of inorganic salts leads to fast ruining of colloidal character, which completely devastates the effect of the surface enhancement. The common stabilization of nanoparticles by a layer of polymers has a negative impact on the SERS sensitivity since it shields the nanoparticle surface from the analytes. In this work, we aim at the development of the bi-ligand system of nanoparticles surface modification for improved stability of colloid in saline solution at sustaining the potential for sensitive SERS analyses. The proposed system relies on the binding of 3-mercaptopropionic acid and thiolated polyethylene glycol in a suitable ratio onto the nanoparticle surfaces. While the short chains of the acid sustain the accessibility of the surface for analytes, the polymeric structures act as a steric barrier preventing colloid aggregation.

In the modern world, we are confronted with antibiotic resistance to bacteria and the associated risks for human and animal lives. This phenomenon is widespread causing the greatest problems especially in healthcare facilities. Antibiotic resistant bacteria can be spread also during food production, and food processing by cross-contamination from various food contact surfaces. These bacteria are often found on surfaces in persistent form - bacterial biofilm, often accompanied by additional resistance to sanitizers and disinfectants. Due to the high resistance to current strategies for the prevention of bacterial infections, new active compounds and materials are being sought, which would successfully and permanently allow the control of harmful bacteria. With such a potential, different nanoparticles are being researched. We synthesized molybdenum oxide nanoparticles in orthorhombic crystal structure, which have different size, shape, specific surface area and stoichiometry. We will present chemical and physical characterization (UV-Vis spectroscopy, SEM, BET, zeta potential, pH) of molybdenum oxide nanoparticles, and their antibacterial activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Pseudomonas aeruginosa tested in aqueous solution and complex medium. We will show that the antibacterial activity in complex medium is strain-specific and also dependent on the used nanoparticles. However, the antibacterial function is the most effective in aqueous solution, where the particles are dissolved and form acidic environment, but it is substantial also in growth medium, where another mechanism of antimicrobial function is indicated. A high antimicrobial activity of these nanoparticles presents many possibilities for development of new antimicrobial materials and further applications.

Metal nanoparticles proved to be effective signaling tags in combination with laser ablation followed by inductively coupled plasma mass spectrometric detection. The surface may be suitably modified by various biorecognition elements such as antibodies or aptamers. Moreover, molecularly imprinted polymers can be prepared on their surface. In this study, the biorecognition capabilities of nanoparticles functionalized by antibodies and molecularly imprinted polymers were compared.

3D printing is a modern and widely used technology that has reached virtually all sectors of human activity, from the automotive industry to medical fields. Silver nanoparticles (AgNPs) have considerable industrial potential and are intensively studied regarding their antibacterial capability. Using green synthesis, the nanoparticle surface can be coated with molecules that exhibit biologically significant properties. By combining 3D printing technology and antibacterial activity of AgNPs, a unique antibacterial material can be prepared. The aim of this work was to modify the printing filament with AgNPs, to prepare the antibacterial material by 3D printing and to test the antibacterial activity of the prepared material using the JIS (Japanese industrial standards) L 1902 method. Such material can be used in hospital facilities to adjust various devices to prevent nosocomial infections.

The contact surfaces are frequently colonized by various microorganisms, because they have a good environment for colonization and further growth on them and therefore also represent a site for the transmission of infections. They can form biofilms for their sheltering against disinfection. Coatings with antimicrobial function represent a promising approach to avoid adhesion of bacteria and their growth on the different surfaces used in public environments (e.g. food packaging industry, healthcare and hygienic products, textiles, filters, membranes for cooling devices,…).
The antimicrobial surfaces with a long-term activity can be achieved by the modification of various materials (e.g. polymers, metals) with molybdenum trioxide (MoO3) nanoparticles. Nanocomposites composed of inert poly(vinylidene fluoride-co-hexafluoropropylene), biocompatible, bioinert and water soluble polyvinylpyrrolidone-PVP and molybdenum oxide-MoO3 nanowires synthesized from Mo6S2I8 nanowires have been prepared. We will present chemical, physical and microbiological characterization of these nanocomposites. Results of structural characterization (X-ray diffraction, scanning electron microscopy-SEM), optical absorbance (UV-Vis spectroscopy), vibrational analysis (Raman spectroscopy), surface topography (atomic force microscopy-AFM), wetting angle, and solubility in water decreasing its pH value, will be presented. The proportion of surviving bacteria Staphylococcus aureus and Escherichia coli on the contact surface at different time periods after exposure will be disclosed. Finally, we will present the possibilities of using this nanocomposite as a part of contact surface coatings or membranes in industry.

Nucleobases are the main building blocks in DNA and RNA playing very important roles in cell metabolism. Changes of bases in DNA sequence may affect function of products of gene expression - proteins, and this can lead to inherited diseases and most human cancer types. Pharmacological studies, clinical diagnosis and others areas need a quick, inexpensive and exact method for determination of nucleobases. In this work, we explore the possibility of improving detection of nucleobases by using capillary electrophoresis in combination with isolation by magnetic particles modified by molecularly imprinted polymer.

A quantitative comparison was made of the efficiency of conjugation of immunoglobulins G and gold nanoparticles obtained by the Turkevich-Frens method. The conjugates were synthesized by physical adsorption and covalent immobilization using orthopyridyl disulfide polyethylene glycol succinimidyl ester (OPSS-PEG-NHS). The study is conducted using an original method of determining the composition of protein nanoconjugates based on measuring the intrinsic fluorescence of tryptophan in the protein. The percentage of bound immunoglobulins was higher when using OPSS-PEG-NHS: 43% versus 22% for adsorption conjugation at an added IgG concentration of 2.3 μg/ml. After increasing the IgG concentration to 4.6 μg/ml, the percentage of binding immunoglobulins was close for the two methods of the conjugation: 26% and 22%, respectively, which may indicate the filling of the surface of the particles.

Hierarchical structures found in nature exhibit specific properties such as low wettability or low reflectance. The aim of this initial study is to present the behaviour of a synthetic hierarchical structure prepared by the replication of plant surfaces, such as from the pansy flower. Natural materials serve their purpose for the necessary time. Synthetic hierarchical structures should be used in technical practice in the long term, for precisely required purposes. However, they do not have self-repairing capabilities, since they are not dynamic but static systems. The polyethylene used to replicate the selected natural structure shows very good results and the prepared replicas match the natural patterns very well. In addition, polyethylene is a commercially available, easy-to-process material with satisfactory mechanical properties. Its disadvantage is easy scratching of the surface. Depending on the material used and the specific nature of the surface structure, different pH environments (pH 5, pH 9) were selected for the evaluation of degradation. Circulating water with quartz sand particles of 20 to 60 microns were selected for surface abrasion simulation. Furthermore, the degradation test of samples in an outdoor environment and evaluation of selected substances adsorption on the sample surface was performed. The degradation processes were monitored and evaluated for 1 month in this initial study. Scanning electron microscopy was used as a basic method for characterization of polymer replicas surface changes.

The AgNPs have considerable industrial potential and are intensively studied with regard to their antibacterial properties. Using green synthesis, the nanoparticle surface can be coated with molecules that exhibit biologically significant properties. Increased use of nanoparticles enhances the risk of their release into the environment. However, there is still little known about the behaviour of AgNPs in the eco-environment. In this study, the effect of AgNPs prepared by green synthesis on germinated plants of maize was investigated. The effects on germination, basic growth and physiological parameters of the plant were monitored. AgNPs and silver nitrate were applied to maize seedlings (5 days in hydroponics system) at concentrations of 1 mg/L, 50 mg/L, and 150 mg/L. Chlorophyll a and b content was determined. We found that the growth inhibition of the above-ground parts of plants was about 40 % and AgNPs and silver nitrate had a significant effect on photosynthetic pigments. Chlorophyll a and b content changed with time and concentration.

Silver nanoparticles (AgNPs) exhibit excellent antibacterial effects against both Gram-positive and Gram-negative bacteria. They represent a possible way to combat bacteria resistant to conventional antibiotic treatment. Over time, bacteria also become resistant to AgNPs. One solution is to modify the AgNP surface with various simple or more complex biomolecules with antibacterial activity. Such modifications can be achieved using so-called green synthesis. The green synthesis of AgNPs is based, for example, on the use of plant extracts as reducing agents. The AgNPs obtained have biomolecules derived from the extract bound to their surface. The aim of this work was to identify other plant species with a high content of secondary metabolites with the potential antibacterial activity that would make them suitable for green synthesis. A large number of plants occurring in tropical areas of Vietnam contain a lot of hitherto unspecified substances with the potential antibacterial effect. Nanoparticles prepared using extracts of harvested plants were characterized by physical and biochemical methods. Silver nanoparticles with the modified surface can be used to combat resistant bacteria.

In this work, we focused on the green synthesis of silver nanoparticles (AgNPs). In the green synthesis, plant extracts are used as reducing agents. AgNPs contain surface-bound biomolecules from the used plant extract. We used an aqueous extract from sage (Salvia officinalis). This plant is known for its high content of secondary metabolites with excellent antibacterial activity. Antibacterial activity of AgNPs prepared by green synthesis was investigated. Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli were selected for testing. Methods such as agar diffusion assay and inhibition of bacterial growth curves were used. Minimum inhibitory concentrations (MICE. coli = 250 µg/mL; MICS. aureus = 50 µg/mL) were determined. The radiuses of inhibition zones were about 1.5 cm in both bacterial strains. AgNPs prepared by this method can play an important role in dealing with the problem of bacterial resistance. Bacteria develop resistance not only to typical antibiotics. Bacterial cells are also able to eliminate the effect of AgNPs. By modifying their surface with antibacterial molecules, resistance can be effectively combatted.

Suitable molecular or biochemical markers are sought for rapid diagnostics of cancer. A very promising candidate is the sarcosine (SAR) amino acid, which is elevated in the urine of the patients with prostate cancer. The aim of this work was to develop a simple, fast and reliable method for SAR detection in human urine. Sarcosine oxidase hydrolyses sarcosine and the resulting peroxide is converted to a colored product. By colorimetric analysis, sarcosine could be detected at low concentrations, limit of detection (LOD) was 1 µM and limit of quantification (LOQ) was 6 µM in artificial urine. As a quick test for the presence of sarcosine in urine, a visual assessment of color change has been proposed. Visual results were evaluated as RGB signal densities. The obtained results show that the average RGB variability between test samples was about 10 %. From these values, the ROC curve of the individual experiments was determined. Sensitivity (from 0.59 to 0.83) and specificity (1.00) were calculated using ROC curves according to the type of artificial urine. ROC curves were more than 25 % rated as excellent, 65 % as very good from 5% as good and none as unsatisfactory. Conclusion: Colorimetric detection of sarcosine in urine was sensitive. Visual evaluation of the test showed 100% success in identifying the presence of sarcosine in artificial urine. The obtained data show the potential of the method for the visual evaluation of the presence of sarcosine in the urine and its possible use in the diagnostics of prostate cancer.

We propose a novel black gold-like structure on the base of plasmonic nanostructures incorporated in the MOFs cavities for potential application in solar energy and photochemistry. Mean hybrid structure was prepared by sputtering of gold on the MOFs decorated substrates. Since the size of gold nanostructures, created during the deposition procedure is smaller than the size of pores in MOFs, the gold atoms filled the 3D MOFs structure and formed the nanostructures with wide distribution of sizes and shapes. The surface and bulk properties of created hybrid materials were carefully characterized. In particular, the presence and distribution of gold nanoparticles was confirmed by SEM-EDX and TEM measurements. Plasmonic properties were characterized by UV-Vis spectroscopy and SERS measurements using R6G as model analyte. Our results suggest that created hybrid material is a potential candidate for application in the field of black gold utilization, for example affective light absorber and convertor.