Seznam abstraktů 2024: POSTEROVÁ SEKCE C

Nonstoichiometric molybdenum oxide (MoOx) nanomaterials are promising photothermal nano-agents capable to respond to near IR irradiation with rapid heating. Combining with active targeting elements a selective cancer eradicating platform can be built. RGD peptides (amino acid sequence Arg-Gly-Asp) are recognized by cell adhesion receptors, called integrins (specifically αvβ3, αvβ5, and α5β1), which are highly expressed on the surface of multiple cancer cell lines, but absent on epithelial and mature endothelial cells. Despite a decade of research, MoOx nanomaterials remain a significant player in the field of cancer treatment, exhibiting ongoing scientific interest. Here, we demonstrate for the first time the potential behind MoOx-RGD nanoconjugates in selective cancer treatment. Studies on cell viability, internalization rates, process of binding of nanoparticles and cell death upon photothermal treatment were conducted. Our investigations demonstrated that MoOx-RGD nanoconjugates are highly effective and selective in destroying cancer cells. These findings highlight the potential of MoOx-RGD nanoconjugates as a novel therapeutic approach for cancer treatment. ACKNOWLEDGEMENT: This work was supported by the Slovak Grant Agency for Science under contract No. VEGA 2/0117/22, the Slovak Research and Development Agency contract No. APVV-20-0485 and SK-FR-22-0012, and by DoktoGrant SAS No. APP0492.

The diagnosis of numerous illnesses relies on the sensitive detection of clinical biomarkers. It is of the utmost importance especially in the case of tumor diseases, allowing for early-stage cancer diagnosis and monitoring of treatment response. Due to the high specificity provided by antibodies, various kinds of immunochemical assays are used for this purpose. However, conventional immunoassays often provide insufficient sensitivity for the detection of low-abundance biomarkers. A common strategy to enhance immunoassay sensitivity involves replacing conventional labels with nanoparticles. Photon-upconversion nanoparticles (UCNPs) stand out among the most promising options. These lanthanide-doped nanocrystals convert near-infrared radiation into visible light, significantly reducing the optical background. Moreover, their emission spectra can be tuned by altering the dopant ions. The heterogeneous immunoassay format is typically predominant due to its high sensitivity and specificity. However, it requires immobilization and washing steps, leading to a prolonged procedure. Conversely, even though homogeneous immunoassays omit these time-consuming steps, they come at the cost of reduced specificity and sensitivity. To overcome these drawbacks, we have developed a novel artificial intelligence-aided homogeneous immunoassay format based on massively parallel spectroscopy (MPS). This single-molecule method utilizes two different UCNP-antibody labels binding to analyte molecules, detecting only sandwich immunocomplexes containing the analyte molecule and both labels with different doping. We have successfully employed this method in immunoassays for tumor biomarkers prostate-specific antigen and protein p53, proving its high potential. MPS promises to become a fast and high-throughput method for the detection of biomarkers.

The interaction between light and matter can be significantly enhanced through the excitation of surface plasmons, enabling sub-diffraction focusing of light energy. This phenomenon is especially pronounced in the case of the creation of plasmonic hotspots, which have found wide application in surface-enhanced Raman spectroscopy (SERS). This work focuses on the preparation and use of ordered chiral gold nanostructures with unique helical shapes and chirality encoded in each individual nanoparticle. An ordered layer of Au helices with a consistent gap between nanoparticles on a plasmon-active gold grating was fabricated, capable of supporting the excitation and propagation of surface plasmon-polaritons and local plasmons. Chiral molecules of the analyte(s) were placed in the space between Au helicoids (i.e., in the place of the plasmonic hot spots). The influence of the chiral dielectric „spacer“ on the intensity of the local electric field and the SERS response of the enantiomers is investigated. In particular, a significant difference in SERS enhancement was observed, depending on the interplay of helicoids chirality and analytes chirality.
ACKNOWLEDGEMENTS: This work was supported by the GACR under project 23-05197S.

Bacteria resistance to many antibiotics has emerged as a huge problem. This critical health issue necessitates a dynamic approach to produce antimicrobial surfaces to cut the transmission path of microbes from various highly touched objects. Our objective is to develop the transparent daylight triggered photoactive composite polymer. A photochemical reaction occurs when a photosensitizer, embedded in the material, is irradiated with visible light, leading to the generation of reactive oxygen species and creating an antibacterial, self-sterilizing surface.
We describe and focus on the application of the spin trap EPR (electron paramagnetic resonance) technique, using TEMP as a spin trap, for the detection of reactive oxygen species, specifically singlet oxygen, in photoactive materials, before and after incorporation into a polymer matrix. We detect and analyse the production of singlet oxygen at different wavelengths of light (colors) with the aim of developing a photosensitive material with a high quantum yield under daylight conditions and artificial indoor lighting.
The photoactive materials studied include various types of carbon-based materials such as carbon quantum dots, graphene quantum dots, chitosan, etc. Our experiments have demonstrated significant photoactivity of these materials, making suitable candidates for the development of self-sterilizing surfaces. This research contributes to the growing body of knowledge on the use of carbon materials for antibacterial applications, providing new insights into their potential and efficacy. As a results the state-of-the-art products, such as antibacterial door handles, antibacterial cell phone cases, etc have been developed.
ACKNOWLEDGMENT: This research was supported by the Science Fund of the Republic of Serbia, grant no. #7741955,
Are photoactive nanoparticles salvation the global infection threat? PHOTOGUN4MICROBES.

We recently reported the size-controlled synthesis of core-shell FeO/Fe3O4/FeOOH nanocubes (16-23 nm). The PMAO-coated NCs demonstrated the best stability in water (>one year) and good material yield. Powder XRD and Mössbauer spectroscopy identified wüstite, magnetite, and goethite phases in the NCs. XRD data collected over time showed the transformation of wüstite to magnetite. A theoretical model based on the reaction-diffusion Master equation was developed describing the diffusion of O2 into the NC, O2 dissociation accompanied by charge transfer, and the resulting local phase transformation of wüstite to magnetite. The consequent formation of magnetite shell alters the diffusion barriers for further passage of O2, and thus, long-term oxidation proceeds less rapidly. The model gives relatively accurate predictions of the NCs’ oxidation rate at elevated temperatures (annealing). Annealing methods were introduced to enhance the magnetic properties of the NCs. The highest SAR values were found in 20 nm NCs annealed in an organic solvent and 23 nm NCs annealed in water for 48 hours. The SAR values of 16-20 nm NCs were less sensitive to viscosity changes post-annealing than 23 nm NCs. For MRI and MPI applications, T2 relaxivity measurements showed an increased r2 relaxation rate with a larger magnetic domain size, peaking at 20 nm. The 20 nm NCs had an r2 relaxation rate around 300 mM-1 s-1 at 1.5 T, slightly higher than 23 nm NCs. MRI scans confirmed these results, with 20 nm NCs showing the most significant T2 contrast darkening.
(1) Sojková, T.; Rizzo, G. M. R.; Di Girolamo, A.; Avugadda, S. K.; Soni, N.; Milbrandt, N. B.; Tsai, Y. H.; Kuběna, I.; Sojka, M.; Silvestri, N.; Samia, A. C.; Gröger, R.; Pellegrino, T. From Core-Shell FeO/Fe 3 O 4 to Magnetite Nanocubes: Enhancing Magnetic Hyperthermia and Imaging Performance by Thermal Annealing. Chem. Mater. 2023, 35 (16), 6201-6219. https://doi.org/10.1021/acs.chemmater.3c00432.
(2) Sojková, T.; Gröger, R.; Poloprudský, J.; Kuběna, I.; Schneeweiss, O.; Sojka, M.; Šiška, Z.; Pongrácz, J.; Pizúrová, N. Kinetics of Spontaneous Phase Transitions from Wüstite to Magnetite in Superparamagnetic Core-Shell Nanocubes of Iron Oxides. Nanoscale 2024, 16 (11), 5551-5560. https://doi.org/10.1039/D3NR06254F.

Maghemite (γ-Fe₂O₃) is a ferrimagnetic iron oxide that crystallizes in an inverse spinel structure, notable for its biocompatibility and low cytotoxicity. It can be viewed as magnetite (Fe₃O₄) with the introduction of iron vacancies into the octahedral sublattice. While the magnetic behavior of maghemite and magnetite is similar, magnetite exhibits a higher total magnetic moment. Iron oxide nanoparticles related to maghemite have numerous applications, including advanced contrast agents for magnetic resonance imaging, carriers for targeted drug delivery, and heat sources for localized magnetic hyperthermia treatment, among many other profitable uses. These arise from the combination of their unique magnetic properties (high saturation magnetization, low coercivity) and small size.
Although their applications are well studied, a deeper understanding of the structure-property relationship is still highly desired. This motivates our study, in which we employ density functional theory (DFT) calculations to investigate the properties of iron oxide nanoparticles. Our nanoparticle models are based on bulk maghemite (γ-Fe₂O₃), where tetrahedrally and octahedrally coordinated Fe sublattices exhibit opposing magnetic moment orientations. Notably, our findings revealed that the surfaces of the nanoparticles generate significantly more intricate magnetic states compared to the magnetic arrangements observed in bulk maghemite or magnetite. These intricate magnetic states are characterized by what we term "nested" ferrimagnetism, where Fe atoms exhibit locally opposing magnetic moments even within the same (tetrahedral or octahedral) sublattice.

Point-of-care testing (POCT), also known as near-patient testing or bedside testing, is a vital aspect of medical diagnostic testing that is applied directly at the site of need. This type of testing plays a significant role in the diagnosis and subsequent treatment of patients. In the context of the COVID-19 pandemic, POCT has been developed rapidly to improve speed, sensitivity, and ease of use compared to traditional methods like nucleic acid amplification tests (NAAT) and rapid antigen tests. Golden standard laboratory test for detecting active infections reverse transcription-polymerase chain reaction (RT-PCR) requires sophisticated equipment, skilled technicians, and long turnaround times. This all doesn’t meet POCT requirements. To overcome these challenges, isothermal amplifications such as reverse transcription loop-mediated isothermal amplification (RT-LAMP) have become more popular, as they eliminate the temperature cycling step and simplify the process, making it faster, cost-effective, and energy-efficient. RT-LAMP is the most sensitive and specific of the isothermal amplification approaches, utilizing four to six primers that recognize six to eight different regions in the target nucleic acid molecule. Amplification is performed at a constant temperature between 60 °C to 65 °C, eliminating the need for thermal cycling and fluorescence monitoring, simplifying the process, and reducing dependence on complex equipment.
RT-LAMP is an appropriate method for POCT and on-site testing scenarios where immediate results are critical for informed decision-making. RT-LAMP can be monitored in real-time by highly sensitive fluorescence or colorimetry. While fluorescence-based detectors can be complicated for POCT due to the general requirement for bulky and expensive fluorescence instruments, high background, and often inhibition of the amplification process due to the increased dye concentration, colorimetry is simpler and exposed to fewer cross-contamination risks. The color-change is caused by colorimetric indicators, which change color in response to pH shifts during amplification. This option is increasingly attractive for POC applications as it does not require complex equipment and optical modules. In this work, we demonstrate two versatile approaches for POC applications, utilizing fluorescence and colorimetric RT-LAMP analysis using specifically modified magnetic nanoparticles for sample preconcentration and nucleic acid isolation. These systems are highly sensitive, specific, and effective tools with potential in human and veterinary medicine.

Carbon quantum dots (CQDs), crystalline graphitic nanoparticles, have excellent bioapplication potential, especially in bioimaging, because of their fluorescent properties, biocompatibility and water solubility. We prepared the nitrogen-doped CQDs (N-CQDs) from glucose and ethylenediamine using a one-step and fast (a few minutes) microwave-assisted hydrothermal synthesis. The average size of the particles was 3.8 nm, and high-resolution TEM confirmed their crystalline graphitic nature. The carbon structure contained 18.6 at.% of nitrogen and 12.6 at.% of oxygen. The NCQDs exhibited tunable photoluminescence (PL) emission in the entire visible spectral region, which extended to near-ultraviolet and slightly to near-infrared. We demonstrated theranostic applications of hydrothermally synthesized N-CQDs when drugs, e.g., against neurodegenerative diseases. The advantage of such coupling lies in the excellent water solubility of the complexes thanks to N-CQDs and the possibility of imaging the distribution process.

Electrochemical biosensing has shown great interest in two-dimensional (2D) transition-metal MXene-Ti3C2Tx carbide layered materials due to their outstanding conductivity and variable surface chemistry. We developed a ultrasensitive molecular complex for neurotransmitter dopamine sensing by utilizing multilayered MXene (Ti3C2Tx) nanomaterials. Additionally, its on-site application was realized by fabricating a label-free screen-printed carbon electrode (SPCE) for electro-sensing dopamine levels in buffer and serum samples at the point-of-care (POC) testing. Importantly, 4-aminophenyl boronic acid polymerization with high specificity on the MXene-Ti3C2Tx surface for SPCE is easily implemented with the most excellent electrochemical signal amplifying. In this conceptual study, the electrochemical biosensor was logically inexpensive, straightforward, label-free, quick and easy detection of dopamine in clinical samples. It could selectively measure dopamine levels with a limit of detection (LOD) of 2 nM in the human serum sample and 1.3 nM in PBS buffer (pH 7.4). It had a wide range of linear detection of dopamine concentrations of 40 to 500 nM, with a sensitivity of 0.0134 µA nM−1. This study paves a new path for 2-D MXene-Ti3C2Tx/4-APBA modification for biomedical and electrochemical sensing applications at nanomolar concentrations with high specificity.
Acknowledgement: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (RS-2023-00244250)

The green alga Haematococcus pluvialis is highly regarded as a producer of astaxanthin. Due to its antioxidant properties, astaxanthin has become a popular nutritional ingredient. Astaxanthin has demonstrated potential pharmacological effects including antidiabetic, anti-inflammatory, and antioxidant activities and cardiovascular and neurological protective properties. Nanoparticles have become integral components of microalgal technologies, serving as stimulators for the production of biologically active compounds. The stimulating effect of nanoparticles is based on the induction of oxidative stress. In this study, oxidative stress was induced by silver nanoparticles (AgNPs) and combined with stress from a nutrient-deficient cultivation medium. Citrate-stabilized AgNPs of 10 nm and 20 nm were used. They were applied to the mineral medium from the first day of the cultivation cycle in concentrations ranging from 0.01 mM to 10 mM. The microalgal culture in the red cyst phase was used as the inoculum. The results demonstrated a significant increase of 80-90% in the astaxanthin content in the biomass of the red cysts without altering the biomass content. Additionally, the lipid content in the biomass also increased significantly. The dose/effect relationship between the concentrations of 20 nm AgNPs and astaxanthin values was direct. For 10 nm AgNPs, low concentrations resulted in increased astaxanthin values. Combined stress, with the variable factor being the concentrations of silver nanoparticles, can be proposed as a strategy in the biotechnology of Haematococcus pluvialis for astaxanthin production.
ACKNOWLEDGEMENTS: This work was supported by a grant of NARD, project number 24.80012.7007.08 SE

Titrated extract of centella asiatica (TECA) has drawn attention as a functional cosmetic compound by the virtue of its anti-inflammatory, antioxidant, and wound healing activity, but its feasibility has been limited due to its low water-solubility and stability, and extensive studies have been devoted to overcoming these limitations. In this study, we suggest a bilayered micelle, or so called bicelle, as a novel nanocarrier for dermal delivery of TECAs. The physicochemical properties of TECA-loaded bicelles were investigated and their skin permeability and therapeutical efficacies were evaluated. TECA-loaded bicelles were prepared via the hydrodynamic focusing method. To visualize the penetration depth of bicelles, coumarin-6 was incorporated into the bicelles and fluorescent images of vertically cryo-sectioned samples were obtained. Anti-inflammatory activity and wound healing activity of TECA-loaded bicelles were evaluated using HaCaT and HDF cells. In conclusion, the bicelles entrap and protect the non-water-soluble molecules as with liposomes, but the small size and discoidal shape enables the deeper penetration and higher therapeutical effect.
ACKNOWLEDGMENTS: This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (RS-2024-00356054, RS-2024-00432685

Nanodiamonds (ND) exhibit specific bulk and surface properties that predispose them to a wide range of applications. For example, their positive zeta potential after hydrogenation makes them attractive e.g. for drug delivery or selective sequestration of specific cell signalling molecules. Here, we exploit the positive zeta potential of hydrogenated high pressure high temperature NDs and investigate their applicability as carriers for antibacterial silver nanoparticles (AgNPs). The preparation of the AgNP-ND nanocomposites was carried out in two steps. In the first step, the surface of hydrogenated NDs was coated with a thin chitosan layer, which acts as an anchoring element for the reduced silver nanoparticles and simultaneously improves the stability and dispersibility of the NDs in ionic environments and protect them during sterilization. In a second step, silver nanoparticles were prepared in situ by reduction from AgNO3 precursor and anchored to the surface of the nanodiamonds. The final AgNPs-ND nanocomposites retain a positive zeta potential and enhanced colloidal stability which allowed efficient attachment to the negatively-charged gram-positive and gram-negative model bacteria. We found out that while AgNPs on NDs 0 - 30 nm in size show an antibacterial effect, AgNPs attached to 0 - 250 nm NDs show no significant effect on bacterial growth. This principle can be utilized for the preparation of nanocomposites with scalable antibacterial effects while preserving the specific properties of each ND and AgNPs constituents.

The potential application of fluorescent gold nanoclusters in drug delivery monitoring is becoming more apparent. These nanoclusters have been effectively employed as fluorescent markers for imaging of cells and tissues. Furthermore, one of the main areas of research is the creation of biosensors using structure-tunable fluorescent nanoclusters. Selective identification of, for example, metal ions, tiny compounds with neuroactive or antioxidant effects, or proteins is usually the aim of these sensor applications. In general, there is not enough time during these application-focused advances to thoroughly investigate the thermodynamically-driven interactions between nanoclusters and pertinent biomolecules and proteins. Thus, the main goal of this work is to conduct several experiments in order to partially fill this scientific gap. Besides the well-known fluorescent probes, the cited interactions were investigated applying unconventional methods as surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). These two-dimensional (at the solid/liquid interface) and three-dimensional (in the bulk phase) measuring arrangements provide a unique opportunity for the thermodynamic characterization of the interaction between different gold nanoclusters containing various surface functionalizing ligands and proteins.

Bone tumors present a formidable challenge due to their mineralized extracellular matrix predominantly composed of hydroxyapatite, which hinders the effective delivery and action of anticancer agents. Herein, we present a novel bone tumor-targeting polymeric nanoparticles (NPs), named PLCSA-AD NPs, comprising alendronate-decorated chondroitin sulfate A-graft-poly(lactide-co-glycolide) and doxorubicin (DOX). These NPs demonstrated a prolonged retention within the tumor microenvironment and enhanced therapeutic efficacy by inhibiting the mevalonate pathway. The PLCSA-AD polymer was synthesized through a coupling reaction of chondroitin sulfate A (CSA) and poly(lactide-co-glycolide) diamine (PLGA-NH2), followed by subsequent coupling of alendronate (AD). PLCLA-AD NPs were then fabricated by loading DOX via a self-assembly process. PLCSA-AD NPs exhibited a 1.72-fold lower IC50 value than free DOX and displayed a higher affinity for hydroxyapatite compared to PLCSA NPs in HOS/MNNG cell-based bone tumor models. The inhibition of the mevalonate pathway by PLCSA-AD NPs in tumor cells was confirmed by examining the cytosolic fraction of unprenylated proteins. Blank PLCSA-AD NPs notably increased the expression of cytosolic Ras and RhoA without altering their total cellular levels. In a bone tumor-mimicking xenografted mouse model, PLCSA-AD NPs significantly enhanced tumor accumulation compared to PLCSA NPs, with histological analysis revealing increased adsorption to hydroxyapatites within the tumor. Collectively, bone tumor-targeting PLCSA-AD NPs achieved prolonged retention within the tumor microenvironment through ion interactions with hydroxyapatites and facilitated apoptotic process via mevalonate pathway inhibition.

Molybdenum oxide represents a material with promising photothermal activity which is able to induce apoptosis in cells after irradiation with near-infrared laser. By functionalization of MoOx nanoparticles (NP) with antibody against carbonic anhydrase 9 (CAIX) we have enabled specific targeting of cancer cells. Transmembrane protein carbonic anhydrase 9 is a biomarker associated with aggressive tumors and poor clinical outcome. We have characterized biological properties of functionalized NP, such as their binding selectivity, influence on cell rigidity, kinetics of NP binding and their membrane and intracellular localization. We confirmed their biocompatibility by viability measurements. MoOx NP functionalized with anti-CAIX antibody bind to CAIX present on the cell surface, followed by the internalization of NPs and their transport by endocytic pathways. Characterization of the functionalized nanoparticles and of their interaction with target cells represents an important step in the development of a multifunctional nanoplatform for cancer therapy.
ACKNOWLEDGEMENT: Supported by APVV-20-0485, APVV-20-0480, VEGA 2/0117/22, SK-FR-22-0012

Pharmaceuticals can be found in soil and aquatic environments as a result of human activity. They are released into the environment where they undergo soil sorption, photodegradation, and chemical transformation. It is known that their migration ability and toxicity can be significantly affected by interactions with organic matter. The interactions can result in their immobilization in humic structure and decrease in their bioavailability. Humic substances as important constituents of natural organic matter are investigated from point of view of their interactions with different pollutants (including pharmaceuticals) mainly by means of traditional batch adsorption experiments. Our approach is different. Humic substances are used in the form of hydrogel which can be considered as a model system of soil with characteristic content of organic matter. The hydrogel form is advantageous for its defined parameters which can be reflected in initial and boundary conditions necessary for mathematical description of transport in the system. Ibuprofen (sodium salt) and tetracycline are studied from point of view of their transport and immobilization in humic hydrogel by the method of instantaneous planar source. It means that small defined amount of diffusing substance is placed on the circular surface of cylinder-shaped hydrogel (placed in glass tube to achieve one-dimensional diffusion). Diffusion coefficients for both studied pharmaceuticals are determined. Their mobility in humic systems as well as the immobilization ability and their effect on the bioavailability of pharmaceuticals are discussed.

The health of the vaginal microbiota is a crucial component of an intricate system. Vaginal drug delivery systems play an integral role in women's health by offering targeted and efficient treatment options for various gynecological conditions, while aiming to minimally impact said bacterial population. We propose using nanofibrous materials based on the polymers polycaprolactone (PCL) and poly(lactic acid) (PLA) due to their favorable properties. The molecular weight of PCL can significantly influence the properties of blended nanofibers, which in turn affects their interaction with the vaginal microbiome. Higher molecular weight PCL tends to enhance the mechanical strength and stability of the nanofibers, potentially leading to a more controlled and sustained release of incorporated substances. This controlled release is crucial for maintaining a balanced microbiome, as it may help in the gradual release of antimicrobial agents or probiotics.
A healthy vaginal microbiome is dominated by various types of Lactobacilli, which produce lactic acid and antimicrobial compounds. We tested the effect of blended nanofibers with PCL of two molecular weights (Mn 45,000 and 80,000) on the growth rate of three Lactobacilli species: L. crispatus, L. gasseri, and L. jensenii. There was no distinguishable effect on the growth rates of L. crispatus and L. gasseri, but the growth rate of L. jensenii was affected by PCL of both molecular weights. This is an important finding for future use of PCL based nanofibers in vaginal drug delivery.

Creatine is synthesized primarily in the liver and kidneys from amino acids and is phosphorylated to phosphocreatine, which serves as an energy source in muscle. Creatine is non-enzymatically degraded to creatinine at a constant rate and excreted in the urine. Its formation mainly depends on the muscle mass. Changes in creatine and creatinine levels may be related to various diseases (e.g. kidney disease, rhabdomyolysis etc.). Several methods are used to determine creatinine, such as for example the Jaffe method using the reaction of creatinine with picric acid in an alkaline medium, forming a red-orange complex or the enzymatic Trinder reaction. In some cases, crystals or larger aggregates are present in the urine. Primary diagnosis of such crystals is focused on microscopic evidence of the presence of the structure and may be confirmed by FTIR. The three enzymes, creatinase, creatininase and sarcosine oxidase can also be used for qualitative assessment of creatinine. The aim of this work was to design a SPION nanobiosensor for qualitative proof of the presence of creatinine in a sample. The methodology uses the highly sensitive Red Amplex fluorophore. Absorbance dependence on creatinine concentration read off at the wavelength of 572 nm was linear over a total range of 0-1000 μM.

While electrochemical biosensors hold promise for enabling the development of multiplexed point-of-care diagnostics, their commercial viability has been hindered by challenges such as electrode biofouling and the absence of inherent redox properties. We have successfully developed a universal nanocomposite coating which is the first of its kind to not only allow the oriented conjugation of the biorecognition element but also enable specific detection directly in complex biological fluids such as urine and serum due to its inherent antifouling and redox capabilities. This multifunctional coating comprises a 3D porous matrix of cross-linked bovine serum albumin (BSA) embedded with graphene nanosheets functionalized with amino-ferrocene (Fc-GNS). The components and functions of this coating include: (i) A 3D BSA matrix that facilitates oriented covalent conjugation of the biorecognition element, eliminates biofouling, and permits analyte diffusion through its pores without hindrance. (ii) Embedded Fc-GNS for enhanced conductivity and mediator-free biosensing directly in complex biological fluids. Our developed nanocomposite coating exhibited outstanding antifouling properties even after a month-long incubation in 1% BSA, artificial urine, and untreated human serum. For proof-of-concept feasibility studies, we employed the nanocomposite coating-modified electrodes for electrochemical immunosensing of two bladder cancer protein biomarkers, namely IL-8 and VEGF. These electrochemical immunosensors achieved a remarkable limit of detection (LOD) of 41 pg/mL for IL-8 and 67 pg/mL for VEGF, a broad sensing range of 0.1 to 1000 ng/mL for both biomarkers, and a high specificity against other protein interferents such as NMP-22, FGFR3, and HSA. This universal coating holds significant potential in facilitating multiplexed electrochemical biosensing of a wide array of biomarkers found in biological fluids, thus enabling reliable point-of-care testing for various medical conditions.

This study presents a new approach to address the biofouling challenges in electrochemical biosensors, specifically for detecting estradiol (E2). The approach involved developing an antifouling nanocomposite coating interface (ANcI), which is a combination of natural polymers and advanced nanomaterials. The ANcI consisted of a hybrid hydrogel network formed by crosslinking carboxymethyl chitosan with sodium carboxymethyl cellulose, doped with highly conductive Ti3C2Tx MXene nanostructures. This innovative coating provided excellent antifouling properties and high electrical conductivity, crucial for maintaining sensor performance in complex clinical samples. The biosensor was fabricated on a screen-printed carbon electrode by drop-casting the ANcI as an antifouling layer, followed by a gold nanoparticle supporting layer modified with E2-specific aptamers as biorecognition elements. The biosensor's antifouling capabilities were evaluated in human serum and bovine serum albumin, showing promising results. This research addresses the crucial need for reliable E2 detection in clinical diagnostics, environmental monitoring, food safety, and paves the way for enhanced accuracy, sensitivity, and a clinically relevant detection range of 0.1 pg/mL to 1000 pg/mL in electrochemical biosensors.
ACKNOWLEDGEMENT: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) (RS-2023-00243390).

In this study, the reaction mechanisms of gold nanoparticles (AuNPs) synthesis using dialdehyde cellulose (DAC) and dialdehyde hyaluronate (DAH), and their covalent binding to chitosan nanofibers (CHIT), was investigated. The synthesis uses a redox reaction where dialdehyde polysaccharides are oxidized to dicarboxy polysaccharides and the gold salt precursor is reduced to elemental gold. The formation of the AuNPs-CHIT composite involves Schiff base chemistry, where reactive aldehyde groups of the polysaccharide shell around AuNPs react with chitosan's amine groups, forming pH-labile imine groups, which can be subsequently stabilized using reductive amination. FT-IR and XPS analyses were used to confirm the proposed reaction mechanisms. Next, the catalytic activity of AuNPs synthesized using DAC and DAH was evaluated for the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride. Rapid conversion rates and high turnover frequency were observed. The morphology and structure of the composites were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). These analyses confirmed the sub-10 nm size of the AuNPs and their uniform distribution on chitosan nanofibers. The findings confirm the proposed reaction mechanisms, showcase the morphology and catalytic activity of the prepared nanoparticles and highlight their potential industrial applications. The versatility of this method also opens avenues for further functionalization and broader applications of AuNPs in biomedical fields such as biosensors and drug delivery systems.

Hyaluronan (HA) or its derivatives are often considered as a suitable material for application in regenerative medicine, cosmetics, or dermatology. HA is a natural polysaccharide present in the extracellular matrix, synovial fluid, cartilage, and skin and at the same time it plays an important role, e.g. in the wound healing process. HA or its derivatives can be processed into various morphological forms to enhance their key properties. By a combination of these forms, it is possible to eliminate partial shortcomings and achieve a remarkable synergy.
Composite materials consisting of a HA nanofibrous layer containing an active substance (AS) and a thin film based on hydrophobized HA derivatives were prepared. Such a material could be used, for instance, as a wound dressing. Nanofibrous layer dissolves immediately upon contact with wound environment, releasing the AS and forming HA gel. Thin film serves as a mechanical protection controlling the moist environment. The thin film is transparent so the state of the wound could be regularly monitored.
Various composite materials were prepared by combining thin films based on different HA derivatives and nanofibrous layers containing hydrophilic or hydrophobic model AS. Different properties, primarily the adhesion between the two forms and the behavior of the AS under moist conditions were analyzed by the T-PEEL test and the confocal fluorescence microscopy, respectively. To conclude, the optimal combination of the materials and the preparation method were selected to obtain a composite material with sufficient adhesion for standard manipulation and desired behavioral properties of the AS.

The rise of antimicrobial resistance due to extensive antibiotic use has become a critical issue, necessitating the development of novel antibacterial materials. This study investigates the potential of hydrogels incorporating ionic liquids and copolymers of 2-hydroxyethyl methacrylate (HEMA) containing positively charged thiazolium groups.
Hydrogels were synthesized using 2-HEMA and MTA monomers in four distinct molar ratios through free radical polymerization in aqueous solutions. Comprehensive characterization of the hydrogels was conducted using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), rheological assessments, and swelling tests.
The results indicated that increased thiazolium content enhanced the hydrogels' swelling capacity but compromised their mechanical properties and thermal stability. However, these hydrogels demonstrated substantial antibacterial and antifungal efficacy, highlighting their potential in medical and environmental applications. This research underscores the need for advanced materials to combat antimicrobial resistance and positions hydrogel polymers as a promising avenue for further investigation.
ACKNOWLEDGEMENT: This work was created as part of the project No. CZ.02.01.01/00/22_008/0004631. Materials and technologies for sustainable development within the Jan Amos Komensky Operational Program financed by the European Union and from the state budget of the Czech Republic and with the financial support of the European Union under the REFRESH - Research Excellence For REgion Sustainability and High-tech Industries project number CZ.10.03.01/00/22_003/0000048 via the Operational Programme Just Transition.“

Nowadays, additive manufacturing in the form of three-dimensional printing is an up-and-coming technology in regenerative medicine and tissue engineering. The growing popularity of this technology in the biomedical community is due to its versatility in terms of approach to processing, choice of materials and final design. With the possibility of using a whole range of thermoplastic biodegradable polymers with various properties, the subject of current research is mainly the printing technology based on the deposition of extruded thermoplastic polymer - FDM / FFM. One of these thermoplastic polymers is polydioxanone, a biodegradable polyester with excellent mechanical properties, thanks to which it can be used in surgery as implants. In particular, the degradation profile of printed samples needs to be extended for broader application in orthopaedic chiropractic. Therefore, this research focuses on the subsequent plasma treatment of printed polydioxanone implants. The goal is to extend their degradation time by increasing hydrophobicity via forming a thin film deposited from hexamethyldisiloxane. This work compares the effect of plasmatic surface modification on the resulting biocompatibility of the material, surface texture, and change in contact angle to the unmodified sample.
ACKNOWLEDGEMENT: The research was supported by the SGS project Reg. No. ​
SGS-2024-6426 funded by the Ministry of Education, Youth and Sports (CZE) in 2024​.

Arthrospira platensis (spirulina) is known for its high biological activity, including antioxidant, anti-inflammatory, and antiviral properties. In recent years, spirulina polysaccharides have been actively researched in fields such as tissue engineering, targeted drug delivery, and wound healing. These substances also possess a high reducing capacity, making them suitable matrices for the biosynthesis of metallic nanoparticles from metal ions. For instance, silver, known for its antimicrobial properties, can be biosynthesized as AgNPs on polysaccharide matrices derived from spirulina biomass, potentially combining the effects of the nanoparticles and the matrix for developing wound coverings.
In this study, sulfated polysaccharides were extracted from spirulina biomass grown under controlled conditions to stimulate carbohydrate accumulation. AgNPs biosynthesis was carried out using polysaccharides solubilized in deionized water at 10 mg/ml and AgNO3 solutions of various concentrations, under different process parameters. The nanoparticles obtained were tested for antibacterial properties against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and antifungal properties against Candida albicans. The AgNPs demonstrated significant antimicrobial activity, with MIC and MBC values varying based on the biosynthesis conditions. These results indicate that AgNPs biosynthesized on spirulina sulfated polysaccharide matrices possess antimicrobial properties, making them promising for developing wound dressing materials.
ACKNOWLEDGEMENTS: This work was supported by a grant of the Ministry of Research, Innovation and Digitization, CNCS-UEFISCDI, project number 12ROMD/20.05.2024, project PN-IV-P8-8.3-ROMD-2023-0060, within PNCDI IV.

Polymer nanofibers have been established as effective structures in a variety of application. Nowadays, they can be found in filtration processes of both gas and liquid media, where the greatest challenge is to maintain their functionality with respect to filtration efficiency and biofouling threat brought by the filtrated substances. For this purpose, the most effective approach is a combination of nanofibrous polymeric material and antimicrobial nanomaterial; the polymeric part can be fulfilled by polyurethane (PUR) and the silver (in a nanoparticle form) can guarantee the antimicrobial action. PUR fibers are mechanically stable and silver has approved to be a reliable antimicrobial agent, which can prevent biofouling of the final composite filtration material and this way prolong the lifespan of the filter. However, the antifouling agent should be covalently immobilized on the surface of the independent fibers, where the prevention of microorganism colonization is likely to start. The functionalization agent of the fibers should be then release-resistant, which can be achieved only with the silver nanoparticles covalently bonded to a linker, which is anchored in the fiber itself. Similar approach can be used also for a safe application of polymer-nanomaterial based composite in the second major application field - in medicinal applications. In this field the poly(lactic-co-glycolic) acid (PLGA), in a form of either particles or fibers, and functionalized in its entire volume or just on the surface with silver nanoparticles, represents a composite material, which brings advantages of both counterparts. PLGA is an FDA approved material for this purpose and a composite of such a material decorated with silver nanoparticles represent a material against which bacterial resistance hasn´t been proved.
ACKNOWLEDGEMENTS: Authors gratefully acknowledge the support of Project TN02000051- Polymer Materials and Technologies of the 21st Century, which is co-financed by the Technology Agency of the Czech Republic under the National Centre of Competence Program and from European Regional Development Fund - Project Excellence in Regenerative Medicine" (No. CZ.02.01.01/00/22_008/0004562).