Seznam abstraktů 2022: SEKCE C - BIONANOTECHNOLOGIE, NANOMATERIÁLY PRO MEDICÍNU

Cellulose is a linear polymer of glucose and a structural polysaccharide of cell walls. Nanocellulose is cellulose in the form of nanostructures, i.e. features not exceeding 100 nm at least in one dimension. There are four main sources of nanocellulose: bacteria (Gluconacetobacter), plants (herbs and woody plants), algae (Cladophora) and animals (Tunicata). From these sources, nanocellulose can be isolated in two main forms: nanofibrils and nanocrystals. Nanofibrils can be prepared by biosynthesis (bacterial cellulose), mechanical disintegration and enzymatic hydrolysis of cellulose or by electrospinning of cellulose derivatives. Nanocrystals are typically prepared by acid hydrolysis of cellulose, which destroys the amorphous regions, while the crystalline segments of the cellulose remain intact. Nanocellulose has emerged for a wide range of industrial and technology and biomedical applications, e.g. for adsorption, ultrafiltration, packaging, energy extraction and storage, acoustics, sensorics, controlled drug delivery, and particularly for tissue engineering. Nanocellulose is promising for use in scaffolds for engineering of blood vessels, neural tissue, bone, cartilage, liver, adipose tissue, urethra and dura mater, for repairing connective tissue and congenital heart defects, and for constructing protective barriers and contact lenses. In our studies, cellulose nanofibers were applied for skin tissue engineering and wound healing. Anionic nanofibers promoted the adhesion and growth of dermal fibroblasts and adipose-derived stem cells (ADSCs), and were therefore suitable for construction of continuous cell sheets, while cationic nanofibers were rather repulsive for the cell adhesion and growth and supported formation of cell spheroids, i.e. structures promising for creation of organoids of skin and other tissues.

Cerium oxide nanoparticles (CeNPs) possess multiple redox enzyme mimetic activities in scavenging reactive oxygen species (ROS) as a potential biomedicine. These enzymatic activities (superoxide dismutase, catalase, peroxidase and oxidase) of CeNPs are closely related to their surface oxidation state. Here we have reported a synthetic method to modify CeNPs’ surface oxidation state by changing the conformation of the poly(acrylic acid) (PAA) polymers adsorbed onto the CeNP surface. In vitro experiments showed no cytotoxic effect of these PAA-CeNPs on the osteoblastic cell line SAOS-2 at high loadings. Microscopic images confirmed the internalization of PAA-CeNPs in the cells. All tested PAA-CeNPs can reduce the basal and hydrogen peroxide-induced intracellular ROS level in the cells, indicating their effective intracellular ROS scavenging effect and thus suggesting their use in fighting ROS in organism.

Antioxidants are capable of scavenging free radicals and preventing oxidation inside the cell. The possibility of developing an efficient antioxidant nanozyme of cerium oxide (ceria) nanoparticles has attracted much research attention. Cerium oxide nanoparticles can be used for regulating reactive oxygen species related to numerous pathological conditions. However, our understanding of applying cerium oxide as efficient nanomedicine remains in its infancy. In this work, the current progress in understanding and developing Advanced Bio Ceria for biomedical applications will be presented. The talk will cover the aspects to answer the following questions: how to stabilize cerium oxide nanoparticles in a biologically relevant environment; revisit the traditional mechanism of how cerium oxide nanoparticles work; how to design cerium oxide nanoparticles with improved catalytic efficiency; and how to design a delivery system to reach a specific target in vitro. In the end, the projected roadmap of a smart delivery system loaded with Advanced Bio Ceria will be discussed as a more efficient antioxidant nanomedicine for regulating pathologically related oxidative stresses.

The release is a transport of active compound from patch to the skin and/or human body. During the material research it is investigated as a release to the model system replacing human body such as hydrogel. The release of active compounds from materials was analyzed by numerical models, which are currently based on simple kinetics and they are used to analysis of release which already ended.
In this contribution, we propose a model, which enables to design complex multi-layered material applied before the experiments in order to design release with desired time-protocol. That approach enables us tailoring the material, where each layer has individual concentration of active compound. The programming work in model provides instructions, for the designing of the materials which are specific for certain situation. The model is connected to real material structures from nanostructured electrospun material, where the layers are pasted together with hydrogel layer. The model enables us to design functional materials which provide behavior of Donnan equilibrium i.e. electrochemical equilibrium on the semipermeable membrane. That functionality enables us to follow the process by electric signal.
The final version of the model will enable us to design the patches in the medicine where the antibiotics, healing or nutrition compounds will be programmed with certain time-protocol. It is assumed that there will be possible to synchronize release of two or more compounds each with different time-protocol.

Hyaluronan (HA) is a natural biopolymer, which commonly occurs in human body (e.g., extracellular matrix, synovial fluids, cartilage). The main specifications of HA are biocompatibility, high solubility, and ability to bind water. It is advantageous for a wide range of medical and cosmetic applications where hyaluronan finds its use. Fibrous structure mostly works as a carrier for incorporation and release of many pharmaceutically active ingredients. In our research group, we focus on the development of various hyaluronan based forms, including thin films, hydrogels, micellar carriers, microfibers and finally, nanofibers.
Hyaluronan nanofibrous layers are prepared in Contipro by electrospinning technology (4SPIN Lab) from precisely designed polymer solutions. However, the preparation of homogeneous nanofibrous layers from a natural polymer, such as hyaluronan, is not entirely straightforward. The following key parameters - proper molecular weight of HA, the choice of the synthetic fiber-forming polymer (regarding its solubility and properties), the concentration and mutual ratio of the polymers in the spinning solution and the continuous and stable spinning process - play an important role. When fulfilled, we obtain smooth nanofibers with uniform thickness and surface morphology, or more complex structures and organization.
Our research is divided into two fields - soluble and insoluble nanofibrous formulations, made of native and chemically modified hyaluronan, or its combination with another natural polymer. Soluble layers are immediately disintegrated while wetted. Insoluble layers are water-stable and preserve the fibrous structure and mechanical properties after wetting. The type of formulation also simultaneously influences the release kinetics of the incorporated additives.

Among interesting novel candidate materials for electrochemical analyses are (i) boron-doped diamond (BDD) or (ii) high surface area carbon nanowalls (B:CNW). The B:CNW and BDD biosensing surfaces are grown by microwave plasma-assisted CVD. The effect of boron incorporation not only enhances the electrical or electrochemical properties but also influences the structure of CNW by changing it from a maze-like to a heterogeneous distribution of nearly straight walls. Both BDD and B:CNW electrochemical electrodes are characterized by outstanding electrochemical properties. For these reasons, they were successfully applied for primary nucleic acid bases detection, paracetamol determination, influenza virus detection, and recently SARS-CoV-2 determination.
The mechanism of interactions of our immunoassay with pathogen protein reveals molecular recognition by impedimetric measurements supported by hybrid modeling results with both density functional theory and molecular dynamics methods. Biosensors allowed for a fast (in less than 10 minutes) detection of SARS-CoV-2 virus with a limit of detection from 0.227 ng/ml. The binding of the viral protein to the antibody sites at the electrodes leads to a change in electrochemical impedance that is transduced into a highly sensitive electrical detection signal. The platform was tested on real clinical samples received from the diagnostic laboratory and verified with RT-PCR. All clinical samples were tested simultaneously on biosensors and real-time polymerase chain reactions. Taking into consideration achieved properties, the studied electrodes could be applied in the point-of-care (PoC) diagnostic systems, which are currently one of the fast-growing areas of health care.

Non-small cell lung cancer (NSCLC) type is among the highest death incidents that can be diagnosed in early stage by quantification of miRNA-21 as a biomarker. Quantitative polymerase chain reaction (qPCR) analysis results showed that the plasma miRNA21 expression level for NSCLC diagnosed to healthy population can be estimated to 1.308, with approximate specificity of 67.7 %. Furthermore, PCR technique is prone to false positive results and the analysis time reaches up to 6 h.
Therefore, implementing an optical sensing approach based on Nanozyme-Aptamer system was developed for quick and simple determination of miRNA-21. Herein, Platinum Nanoparticles (Pt NP)s as nanozymes, with inherent oxidase activity towards TMB (3,3′,5,5′-Tetramethylbenzidine) as the substrate have been prepared. The prepared Pt NPs catalyze the oxidation of TMB to TMBox. The latter emits a blue color which is detectable spectrophotometrically. Also, the surface modification of Pt NPs with tyrosine helps better immobilization of ssDNA aptamer capture probes on the surface by providing hydrogen bonding.
However, in presence of miRNA-21 the capture probes leave the Pt NP surface due to hybridization with target probes. Thus, Pt NPs restore their oxidase catalytic activity and subsequently can oxidize TMB substrate again which is correlated with miRNA target probe concentration. The developed method shows a sufficient sensitivity for precise and accurate detection of miRNA in blood plasma with a good reproducibility. Hence, it can be used in clinical analysis for the preliminary testing of people who are suspicious to lung cancer due to working or health condition.

Two main testing strategies are commonly used to encounter the SARS-CoV-2 infection: either less sensitive, but easy, fast, and cheap lateral flow immunoassay (rapid antigen tests) or expensive and time-consuming but highly sensitive PCR tests. However, rapid yet sensitive detection of SARS-CoV-2 is required to minimize further infections caused by asymptomatic individuals, who exhibit either at the time of testing or throughout the infection a low viral load that might not be sufficient to be detected by rapid antigen tests.
In this work, we developed an upconversion-linked immunosorbent assay (ULISA) which combines the fast turnaround times, high throughput, and superior sensitivity for SARS-CoV-2 detection. Due to the unique optical properties of photon-upconversion nanoparticles (UCNPs) - anti-Stokes emission at visible wavelengths under near-infrared excitation- the ULISA readout can be performed practically without any influence of light scattering or autofluorescence, which can substantially improve the assay sensitivity. In addition, we were able to increase the sensitivity ten-fold by using a modified wide-field epiluminescence microscope to detect and count individual UCNP labels in so-called single-molecule (digital) immunoassay.
The ULISA was based on two capture and two biotinylated detection antibodies. For the label, alkyne-PEG-neridronate -coated UCNPs were modified with click-reactive streptavidin-azide via copper-catalyzed click reaction. This assay setup allowed reaching detection limits of 1.3 pg/mL for the purified N-protein and 0.8 TCID50/mL and 0.08 TCID50/mL for the whole SARS-CoV-2 virus in the analog and digital readouts, respectively.

Prostate-specific antigen (PSA) is one of the most important biomarkers of prostate cancer, the leading cause of death in the male population caused by oncologic diseases. Sensitive biomarker detection is essential for early-stage disease diagnosis, enabling more effective treatment. Immunochemical methods, such as enzyme-linked immunosorbent assay (ELISA), are considered the gold standard for PSA detection. However, there are several limitations that render ELISA insufficient regarding the sensitivity required for early-stage diagnosis.
Photon-upconversion nanoparticles (UCNPs) are nanocrystals that exhibit anti-Stokes luminescence, thus avoiding optical background interference. When conjugated with biorecognition molecules (antibodies or streptavidin), UCNPs can be used as a sensitive label in various immunoassay formats, including microtiter plate-based upconversion-linked immunosorbent assay (ULISA). However, as many biomarkers are present in extremely low levels, even ULISA may still not be sensitive enough, making it necessary to search for new, even more sensitive approaches. Magnetic microparticles represent a promising alternative for microtiter plates used in immunoassays, mainly for their superparamagnetic properties that allow for analyte preconcentration and thus higher assay sensitivity.
We have developed a sandwich immunoassay for PSA based on magnetic microparticles and UCNP-labels. The assay reached an LOD of 93 pg/mL, comparable to an ELISA using identical immunoreagents. With an addtional magnetic preconcentration step, the LOD was improved to 0.46 pg/mL, which was 31-fold better compared to the ELISA. The results demonstrate the potential of using magnetic microparticles combined with UCNPs for the sensitive detection of cancer biomarkers.

The rapid and sensitive detection of protein biomarkers is essential for the early diagnosis and prevention of different kinds of diseases. Recently, lateral flow immunoassays (LFIAs) are becoming one of the most popular forms of tests for the detection of various analytes. The high selectivity of LFIAs is given by specific antibodies. Furthermore, there is no need for laboratory equipment to perform these assays, making them suitable for point-of-care testing (PoCT). Typically, gold nanoparticles are used as a label, allowing naked-eye readout. Even though it is highly convenient for PoCT testing, the sensitivity is not high enough to enable the detection of low abundance biomarkers. Therefore, different kinds of nanomaterials are being studied for use as alternative labels.
Our work focused on the application of photon-upconversion nanoparticles (UCNPs) as a label in LFIA. UCNPs are lanthanide-doped nanocrystals exhibiting anti-Stokes luminescence (excitation by the NIR laser and emission in the Vis region), which allows for the detection without optical background interference. For biological applications, it is important to modify the UCNP surface. We have synthesized UCNPs doped with Yb3+ and Er3+ and conjugated them with specific antibodies. Such conjugates enabled the development of LFIA assays for the detection of different protein biomarkers, such as prostate-specific antigen or human serum albumin. Finally, UCNP-based LFIA was successfully used for detecting protein biomarkers in complex samples of blood and urine. The results demonstrate that UCNPs are a convenient alternative to gold nanoparticles to increase the sensitivity of LFIA tests.

In recent years, dielectric nanostructures have been widely explored for optical (bio)sensing. Dielectric (nano)structures offer numerous attractive features-they exhibit low dissipative losses and support a variety of electromagnetic modes [1, 2] (e.g. bound state in the continuum, Mie scattering, Fano-like resonances, or surface lattice resonances), the evanescent field of which can be tailored for the sensitive detection of specific molecular analytes. The performance of optical affinity biosensors based on nanostructures depends on the performance of the optical system of the biosensor as well as the transport of analyte to the sensing surface with molecular receptors.
In this work, we aim to design a nanostructure that provides high optical performance (expressed in terms of the figure of merit - FOM) and good mass transport efficiency. This is achieved by investigating all-dielectric nanostructures that exhibit pronounced resonance features even at low fill fractions. Three main types of all-dielectric nanostructures are studied, including periodic arrays of symmetric silicon nanodisks, broken-symmetry silicon nanodisks, and broken-symmetry cubes, using the COMSOL simulation software. The effect of various design parameters on the performance of the nanostructures is studied to identify the designs providing the best performance. In addition, biolayer presence is incorporated in the simulations. Our simulations show that nanostructures based on an array of symmetric nanodisks offer an attractive optical platform that provides high-quality resonances even for fill factors much smaller than 1 (i.e. 0.01). Specifically, we demonstrate that the optimized structure (the periodicity, height, and disk diameter of 300 nm, 110 nm, and 100 nm, respectively) can achieve a FOM as high as 37 RIU-1.
REFERENCES: [1] Hsu, Chia Wei, et al. "Bound states in the continuum." Nature Reviews Materials 1.9 (2016): 1-13.; [2] Castellanos et al. "Lattice resonances in dielectric metasurfaces." Journal of Applied Physics 125.21 (2019): 213105.

Fabry-Perot interferometers (FPI) belong to a group of technologically the simples sensing devices, especially when the cavity is obtained using one of the advanced thin film deposition techniques. Their spectral response depends on thickness of the cavity, as well as optical properties of the external media and the cavity. Mass fabrication capability and their sensitivity to changes in optical properties of external medium potentially makes these structures suitable for label-free biosensing applications.
In this work we report a thin-film-based modification of a standard FPI obtained on the end-face of optical fiber and enhancement of functional properties of the device. Both theoretical and experimental analysis performed for the purpose of this work make possible to specify rules for choosing material properties that support obtaining well-spectrally defined interference pattern. Moreover, we show that the pattern shift differently when properties of the interface with external medium (surface) or external medium (volume) changes. The experimental results for various tailored in properties metal and semiconductor oxides deposited on the fiber end-face using magnetron sputtering are reported and discussed from the point of view of label-free biosensing applications of the approach.

In the last few decades, significant advances have been achieved in carbon nanomaterials research. Nowadays, the nanocarbon family spans from fullerene, the first member, to carbon dots (C- Dots), the last to join. This family of materials includes graphene quantum dots (GQDs), considered quasi- spherical nanoparticles with sizes below 10 nm. They typically display excitation wavelength-dependent, excellent photostability, high-water solubility and good biocompatibility. Furthermore, they can be easily functionalized with bio and molecules. GQDs hold great potential in imaging and drug delivery applications.
In this work, the main objective was to obtain GQDs through a bottom-up approach using glucose as a molecular precursor and nitrogen as a doping agent. The as-prepared nanoparticles showed multicolour excitation-dependent in the whole spectra NUV-Vis-NIR. The GQDs proved highly biocompatible by a cell viability assay using human vascular smooth muscle cells. Together with the broad spectral range emission observed in confocal fluorescence imaging, it demonstrated the potential of the synthesized GQDs for in vitro bioimaging applications. Further, GQDs were coupled with several drugs and their activity as a drug delivery system was proved.

Thiorphan is a bioactive small molecule with many proven applications in medicine, such as being a selective inhibitor of neutral endopeptidase and metalloproteinase. In the processes of inhibition of matrix metalloproteinases, zinc, sulfur, and nitrogen atoms have a key role. In spite of its importance, thiorphan adsorption on zinc-containing surfaces such as zinc oxide (ZnO) facets was not studied yet. In this work, for the first time, the adsorption of thiorphan on various ZnO low index facets has been studied by computational methods. Generally, the interactions between ZnO and thiorphan can be affected by ZnO surface atomic structure or ZnO surface polarity. We initially study the effects of ZnO surface atomic structure on ZnO-thiorphan interfaces by employing quantum-based density functional tight binding (DFTB) method. The effects of surface polarity on the adsorption of thiorphan on ZnO surfaces has been then investigated in a larger scale for many thiorphan molecules by using classical NPT molecular dynamic (MD) simulations, to resemble a real experimental situation. Even though the covalent bonding of individual thiorphan molecules to all ZnO facets, except O-faced ZnO, was observed in DFTB simulations, MD simulations by using CO dipole arrays to mimic ZnO surface polarity, show that the surface polarity has the role key in the interactions rather than the surface chemistry. On the C-top dipole array (mimicking Zn-faced surface), the coverage of thiorphan molecules is low and scattered. On the O-top dipole array (mimicking O-faced surface), thiorphan molecules were adsorbed in separated large aggregates. On the horizontally oriented dipole (mimicking ZnO non-polar surfaces) thiorphan molecules assembled into a dense layered structure. These results are corroborated also experimentally by atomic force microscopy, showing small nanodots, large nanodots and nanoislands on Zn-faced, O-faced, and ZnO nonpolar surfaces, respectively.

Anisotropically-shaped magnetic nanoparticles have attracted great attention in the past few years especially with regard to magnetic hyperthermia (MH) and magnetic particle imaging (MPI) applications. The preference for using maghemite- and magnetite-based NPs in vivo follows from their excellent biocompatibility, magnetic properties, and chemical stability at room temperature. The shape, size, monodispersity, and the surface character are controlled by the preparation method.
In this work, we have prepared iron oxide FeO/Fe3O4 core-shell nanocubes in the diameters from 16 to 23 nm by the thermal decomposition method. As-prepared nanocubes were annealed in organic and aqueous enviroments and their resulting magnetic properties were compared. We have also investigated the influence of nanoparticle sizes on their magnetic properties, such as specific absorption rate (SAR), saturation magnetization, magnetic particle imaging properties, T1/T2 relaxation times, and heating efficiency in viscous media. The size distribution, polydispersity index and stability in water were measured by dynamical light scattering. Detailed studies of their crystal structures were made by transmission electron microscopy. The compositions of these nanoparticles were characterised by powder X-ray diffraction and by Mössbauer spectroscopy. Their magnetic properties were characterized by PPMS, MPI, MRI, and T1/T2 relaxometry. The SAR was measured by AC magnetometry in viscous environments and the calorimetric SAR measurements were performed in water.

Cancer, a global health concern when treated with conventional therapies viz. surgery, radiotherapy, and chemotherapy, imposes several adverse effects, presenting an ample need for effective localized treatments. Hyperthermia and targeted drug delivery are accepted as promising modalities in this regard, where superparamagnetic iron oxide nanoparticles (SPIONs) can target the tumor site with the aid of an external magnetic field. Here we present a multifunctional system comprised of superparamagnetic patches prepared by integrating SPIONs into the hybrid biodegradable film synthesized from carboxyl functionalized cellulose nanofiber reinforced chitosan, favoring hyperthermia and magnetic field triggered drug release at the tumor site. The reinforcement of carboxyl functionalized cellulose in chitosan films enhances the mechanical strength and regulates the hydrophilicity and matrix degradation kinetics. Further, the magnetic film samples could be tuned for magnetic, morphological, mechanical, and degradation properties by varying chitosan: SPIONs ratio. The VSM analysis authenticates superparamagnetic properties with high saturation magnetization values, while the SEM-EDX analysis demonstrates the surface texturing of biopolymer films upon the homogeneous distribution of SPIONs along the matrix. The magnetic patches exhibit high mechanical strength (>35 MPa), tumor-specific pH-responsive swelling, biocompatibility, and inherent biodegradability. Additionally, a temperature >41 ºC is acquired in <4 minutes under an alternating magnetic field. The magnetically triggered drug release was studied using Doxorubicin (a clinically used chemotherapeutic drug)-loaded magnetic films, where a 10-fold higher release was obtained in presence of a magnetic field within 1 h. The smart magnetic patches presented here are promising for localized cancer therapeutics in terms of facile preparation technique, heat-induced tumor cell death, enhanced chemotherapeutic effect of Doxorubicin, and circumventing the complications associated with conventional treatment options.

Tissue regeneration still remains a major challenge in orthopedic surgery. Mesoporous bioactive glasses (MBGs) represent a highly attractive bioactive material adaptable in shape, form and application. Moreover, the composition can be richly varied in sol-gel systems based on the specific function of the atoms/ions and their expected action to achieve a certain biological effect. In the last two decades, MBGs have received much attention motivated by achieving optimal interconnected and hierarchical porosity. From this perspective, an important requirement for a scaffold is multi-level porosity with the presence of interconnected macro-channels of tens to hundreds of microns for optimal cell interaction. In addition, the present mesoporous porosity will provide significantly high values of surface area and pore volume ensuring very fast bioactive responses, nanoscale interactions and effective drugs/biomolecules hosting. Sol-gel chemistry offers potential synthesis methods for molecular and textural tailoring which include chemical foaming, replication and templating, freeze-drying, particle/fiber bonding, rapid prototyping or combination of these. Here we summarize the parameterization of synthesis conditions and application challenges for MBGs. In the experiment, we propose the interaction of a precursors based on phosphoric acid and organic compounds. Porosity formation in silica-phosphate gels is induced by phase separation of the surfactant polyethylene glycol. Furthermore, the thermal stability (TGA, TMA) and pore size distribution (MIP, µCT, USAXS) with respect to the incorporation of titanium isopropoxide are studied.

Tissue adhesions still belong to one of the most frequent postoperative complications after pelvis, gyneacologic, peritoneal, tendon and gastrointestinal surgeries. The formation of tissue adhesions between normally disconnected organs may lead to infertility, intestine blockage, pain and reoperation in many cases. There is an urgent need to develop a functional material to prevent such complications since the commercially available products do not fulfill the requirements for successful adhesion prevention. In our study, biodegradable nanofibrous materials with hierarchical structures were introduced. The materials were produced via needleless electrospinning and electrospraying technique Nanospider, which was developed at our Department of Nonwovens and Nanofibrous Materials at the Technical University of Liberec. The nanofibrous material consists of three different parts to mimic the native hydrophobic lotus leaf. The first layer consist of planar nanofibers based on polycaprolactone (PCL), the following layer is created by electrosprayed PCL droplets which are further treated with hydrophobic hexamethyldisiloxane to enhance the hydrophobicity and anti-adhesive properties. The resulting structures were tested in vitro to ensure the cytocompatibility, the morphology and structure was evaluated during the six months period to observe the potential changes. The mechanical testing ex vivo proved the antiadhesive potential of the materials. The nanofibers layers were proven to be non-toxic, stable and were further tested in vivo by using large animal models.
ACKNOWLEDGEMENTS: The research was supported by the project MZ ČR AZV NU20J-08-00009 Prevention of intestinal anastomotic leakage and postoperative adhesions by using nanofibrous biodegradable materials.

Fibrous materials used in regenerative medicine seems to be an ideal structure in terms of tissue ingrowth into the implanted material due to their morphological similarity to extracellular matrix. There is a whole range of fibrous materials (such as PVA, PVB, PCL, TEOS, etc.) developed over the last decade. However purely organic-based as well as purely inorganic-based materials have still many limitations such as fragility or low thermal stability.
This work is focused on the preparation of hybrid organic-inorganic materials made of only N,N'- bis(3-(triethoxysilyl)propyl)oxamide (BTPO) precursor via one-pot synthesis process utilizing an acid catalysed sol gel process and subsequent electrospinning techniques, without the addition of any potentially harmful additives such as surfactants, low-molecular-weight polymeric gelators or spinnable polymers. Such prepared oxamide-based organosilane fibres showed good viability with 3T3 mice fibroblasts. Their viability is better than that of TEOS and approaching PCL nanomaterials, whereby TEOS is frequently employed in biocompatible and biomedical materials. Mentioned fibrous material display various potential applications particularly in the field of regenerative medicine and wound-care therapy due to the presence of active amide bonds which can be used for further functionalization of various types of biomolecules, drugs and/or enzymes. Latest results report the growth of stem cells into neural-like morphology, hence BTPO fibers could be considered as material suitable for neuroregenerative purposes.

Anodized TiO2 nanotube (TNT) layers have been recognized as excellent biocompatible materials owing to their low cytotoxicity, high stability, antibacterial properties, and wetting ability. A pioneering work demonstrated that TNTs with a diameter of 15 nm are the most suitable for the growth of various cells [1].
Recently, we demonstrated that an ultrathin coating on TNT by suitable oxides (e.g. TiO2) using Atomic Layer Deposition (ALD) could enhance cell growth and adhesion [2]. These properties make them excellent as final surfaces for medical and dental implants based on Ti alloys.
The present work investigates and compares the influence of ALD TiO2 and ZrO2 coatings on TNT layers and reference Ti foils for the proliferation of fibroblast cells. Ti sheets and anodized TNT layers with a distinct inner diameter of 12 nm, 15 nm, and 100 nm were used as substrates, as they appear to be the most suitable for cell growth in general [2,3,4].
A part of the TNT layers was coated with five ALD cycles of TiO2 and ZrO2. An increase in cell density for all materials coated by 5 ALD cycles was observed irrespective of the ALD-coated oxide layers. In the presented work, we investigated the shaping, adhesion, proliferation, and cell density on TNTs coated with ALD TiO2 and ZrO2 and the nanotopography. Moreover, the single-cell adhesion of the cells to the TNTs was studied by the bio-atomic force microscopy (bio-AMF) technique [4].
REFERENCES: [1] Park, J.; Bauer, S.; Schlegel, K. A.; Neukam, F. W.; von der Mark, K.; Schmuki, P. TiO2 Nanotube Surfaces: 15 Nm-An Optimal Length Scale of Surface Topography for Cell Adhesion and Differentiation. Nanoparticle growth: Small 6/2009, vintage:5 iss:6 pages:666-671.; [2] Motola, M.; Capek, J.; Zazpe, R.; Bacova, J.; Hromadko, L.; Bruckova, L.; Ng, S.; Handl, J.; Spotz, Z.; Knotek, P.; Baishya, K.; Majtnerova, P.; Prikryl, J.; Sopha, H.; Rousar, T.; Macak, J.M. Thin TiO2 Coatings by ALD Enhance the Cell Growth on TiO2 Nanotubular and Flat Substrates. ACS Appl. Bio Mater. 2020, 3, 6447−6456.; [3] Baishya, K.; Rousar, T.; Macak, J.M. et al., 2022, [Manuscript in preparation].; [4] Baishya, K.; Vrchovecká, K.; Alijani, M.; Pereira, J.R.; Thalluri, S.M.; Goldbergová, M.P.; Pribyl, J.; Macak, J.M. Bio-AFM exploits enhanced Response of Human Gingival Fibroblast (hGFs) on TiO2 Nanotubular Substrates with Thin TiO2 Coatings. 2022, [Manuscript submitted for publication].

Pathogenic microbes such as bacteria and viruses can spread quickly via contaminated surfaces. Most of these pathogenic microorganisms can survive on surfaces for a long time. Touching these surfaces can lead to the transmission of the microorganisms to the human body and cause serious illnesses. ZrN-Cu coatings containing different amounts of Cu were deposited using an industrial PVD system, and their ability to inhibit bacteria and inactivate the SARS-CoV-2 virus was tested. Microstructural studies showed the formation of two distinct ZrN and Cu phases when Cu content was sufficiently high. Hardness and elastic modulus were inversely proportional to the Cu content. The coatings showed outstanding bactericidal properties against Escherichia coli and Pseudomonas aeruginosa, especially when Cu content was more than 12 at.% and exposure time was longer than 40 min. The coatings, however, did not exhibit any significant virucidal properties. Good mechanical properties, along with excellent antibacterial effects, make these coatings suitable candidates for use as self-sanitizing surfaces on objects that people regularly touch and that are prone to bacterial contamination.

Chemical risk assessment is a systematic process integrating data on hazard, exposure, and dose-response relationships of chemical substances to provide information on health risks to exposed populations (e.g. workers, consumers) for regulatory purposes. Sound and reliable risk assessment is a prerequisite for safe and sustainable use as well as successful commercialization of new materials. Nanomaterial risk assessment represents a challenging task, since their adverse effects may be determined, in addition to their chemical composition, by a variety of other parameters (e.g. size, shape, surface charge, protein corona) that can dynamically change depending on interactions with surrounding environments. Moreover, the enormous variability of nanomaterials does not allow to perform conventional risk assessment on a case-by-case basis. Nanomaterials thus fuel the need for adopting innovative, mechanistically oriented, hypothesis-driven, and high-throughput risk assessment tools. A tiered approach is being employed to avoid unnecessary and repetitive testing, and to minimize costly, time-consuming and ethically problematic animal testing, while supporting alternative assays. Preferred methods are based on advanced in vitro biological models and focused on understanding the mode of toxic action. Grouping of nanomaterials allows for data extrapolation (read-across) between nanomaterials and supports moving away from the case-by-case-based risk assessment approach. The lecture will provide a comprehensive overview of the state-of-the-art and emerging risk assessment tools for nanomaterials that aim to improve quality, reliability, and availability of data for regulatory decision-making and safer design of nano-enabled materials and products. ACKNOWLEDGEMENTS: The authors acknowledge the assistance provided by the Research Infrastructure NanoEnviCz, supported by MEYS CZ (LM2018124).

Some metal nanoparticles (NP) are characterized by antimicrobial properties, with the potential to be used as alternative antibiotics. However, NP may negatively impact human organisms including mesenchymal stem cells (MSC), the cell population contributing to tissue growth and regeneration. We investigated the toxic response of mouse MSC treated with antimicrobial NP (Ag, ZnO and CuO) for 4h, 24h and 48h. We characterized NP using dynamic light scattering (DLS), confirmed internalization by transmission electron microscopy, assessed the production of reactive oxygen species (ROS) by a fluorescence-based assay, lipid peroxidation by a 15-F2t-isoprostane (IsoP) ELISA and DNA damage, using the Comet assay and micronuclei analysis. We further investigated sensitivity to the induction of apoptosis by the quantitative RT-PCR analysis of Bcl-2/Bax expression and analyzed cell cycle alterations by flow cytometry. While ROS generation was observed, it was mostly detected after 48h CuO NP exposure. Lipid peroxidation was consistently induced after 4h and 24h exposure, regardless of NP and/or tested dose. DNA fragmentation and oxidation induced by Ag NP, showed dose response for all the time periods. For other NP, the effects were only observed for shorter exposure times. The impact on the frequency of micronuclei was weak, mostly after 48h exposure. All the tested NP increased the sensitivity of MSC to apoptosis induction, the least pronounced response was detected for ZnO NP. The cell cycle was most affected after 24h of incubation, particularly for Ag treatment that increased the proportion of cells in the subG1 phase and decreased the percentage of G1 and S phase cells. In summary, the tested NP induced negative changes in MSC; the biological response differed by the NP type and the exposure time. These results should be taken into consideration when planning the use of NP in medical applications where MSC are involved. Supported by Czech Science Foundation (21-17720S).

The applications of low-voltage transmission electron microscopes range from nanomaterials research to imaging of tissue sections. The combination of TEM, STEM, SEM, electron diffraction and EDS in one device provides a unique variety of analytical methods for complex investigation.
The world's only benchtop transmission electron microscope, LVEM 5, operating at 5 kV, is a perfect solution especially for nanoparticle imaging, chemistry and biochemistry. LVEM 25, with an acceleration energy of 25 kV (TEM) and tailored to the needs of life sciences, is a powerful tool designed to image standard biological sections while maintaining all the advantages of low-voltage electron microscopy. Especially the extraordinary image contrast, even for the samples of the light elements, is invaluable for life science applications. These characteristics predetermine the contribution of LVEMs to nanomedicine, bionanotechnology and other related scientific fields. The lecture will focus on the applications and latest results for which we owe these instruments.