Pokročilé biomateriály

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Biomimetic pHEMA Hydrogels as an Alternative Cartilage-like Model Material for Biotribological Evaluations
(2025-09-20) Kadlecová, Zuzana; Chamradová, Ivana; Tušlová, Klára; Rebenda, David; Čípek, Pavel; Gregora, Jan; Menčík, Přemysl; Vrbka, Martin; Vojtová, Lucy
Poly(vinyl alcohol) (PVA) has been widely explored as a model material for articular cartilage (AC) in biotribological evaluations. However, PVA hydrogels prepared by freeze-thawing or cast-drying methods have limitations in precisely controlling their elasticity parameters and may require reinforcement to enhance their mechanical performance and change their transparency, required in some tribological measurement setups by using fluorescence methods. To overcome these issues, poly(hydroxyethyl methacrylate) (pHEMA) hydrogels have been introduced as alternatives. In our study, pHEMA hydrogels synthesized using free-radical polymerization with blue light under two different atmospheres (nitrogen N2 and air) were compared with natural samples of articular bovine cartilage. The optical, mechanical, swelling, and tribological properties demonstrate the superior properties of pHEMA, which may result in the replacement of the currently used PVA-based model in future studies. Synthesis under a nitrogen atmosphere (pHEMA N 2) resulted in the formation of smooth-surfaced hydrogels, whereas synthesis under a laboratory atmosphere (pHEMA air) resulted in the formation of wrinkled-surfaced hydrogels. The swelling of both the hydrogels and AC followed first-order kinetics. Pin-on-plate biotribology measurements showed that the coefficient of friction of the wrinkled-surface hydrogels resembled that of AC. Our results showed that pHEMA-based hydrogels are suitable biotribological AC models for a better understanding of the biological functions of bovine AC. This knowledge brings new insights into cartilage complex mechanisms and might be applied in both biomedical and engineering applications.
Glycerol-Enhanced Gum Karaya Hydrogel Films with a Sandwich-like Structure Enriched with Octenidine for Antibacterial Action against Multidrug-Resistant Bacteria
(2025-07-02) Černá, Eva; Neděla, Vilém; Tihlaříková, Eva; Brtníková, Jana; Fohlerová, Zdenka; Lipový, Břetislav; Vacek, Lukáš; Růžička, Filip; Matulová, Jana; Vojtová, Lucy
This study explores the innovative approach in the development of freeze-dried hydrogel films, leveraging the unique properties of gum Karaya (GK), poly(vinyl alcohol) (PVA), poly(ethylene glycol) (PEG), and glycerol with a coating of octenidine dihydrochloride (OCT). These innovative hydrogel films exhibit at a certain glycerol concentration a sandwich-like structure, achieved through a tailored freeze-drying process, which enhances transparency and mechanical stability. OCT provides superior antibacterial performance, effectively combating multidrug-resistant bacteria with a controlled and gradual release mechanism, surpassing conventional OCT solutions that require frequent reapplication for infected wound treatment without the creation of bacterial resistance. Advanced environmental scanning electron microscopy (A-ESEM) reveals the complex microstructure of the hydrogel, highlighting the dense surface layer and interconnected porous bulk. Variations in glycerol concentrations proved to significantly impact hydrogels' properties. Increasing the glycerol concentration decreases the pore size (around 4.5 mu m) while enhancing the polymer network density and flexibility. However, low concentration increases the pore size (7.8-15.6 mu m), impacting enhanced swelling behavior and hydrolytic stability. OCT's rapid antibacterial action, releasing over 30% within the first hour and maintaining prolonged activity for up to 2 weeks, emphasizes the material's potential for diverse applications. Hydrogels' remarkable transparency, porosity, structural stability, and antibacterial efficacy against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli strains suggest promising uses as transparent dressings, biomedical devices, and infection-resistant surfaces.
Femoral bone defect healing using two novel biocompatible degradable materials
(Acta Veterinaria Brno, 2020-05-26) Srnec, Robert; Nečasová, Andrea; Proks, Pavel; Skoric, Misa; Filipejová, Zita; Vojtová, Lucy; Nečas, Alois
This study was conducted as an in vivo experiment in adult miniature pigs with the aim to test two new biomaterials. An iatrogenic defect was made into the central femoral diaphysis in the experimental animals and subsequently fixated by bridging plate osteosynthesis. Into the defect we implanted a cancellous autograft (control group), a pasty injectable scaffold (EXP A), anda porous 3D cylinder (EXP B). Radiological examination was performed in all animals at 0, 10, 20, 30 weeks after surgical procedure and histological assessment was performed. In the newly formed bone the osteoblastic activity was monitored. In terms of radiology, the most effective method was observed in the control group (completely healed 100%) compared to experimental groups EXP A (70.0%) and EXP B (62.5%).
In vitro culture of leukemic cells in collagen scaffolds and carboxymethyl cellulose-polyethylene glycol gel
(PeerJ, 2024-12-06) Svozilova, Hana; Vojtová, Lucy; Matulová, Jana; Bruknerova, Jana; Poláková, Veronika; Radová, Lenka; Doubek, Michael; Plevová, Karla; Pospíšilová, Šárka
Background: Chronic lymphocytic leukemia (CLL) is a common adult leukemia characterized by the accumulation of neoplastic mature B cells in blood, bone marrow, lymph nodes, and spleen. The disease biology remains unresolved in many aspects, including the processes underlying the disease progression and relapses. However, studying CLL in vitro poses a considerable challenge due to its complexity and dependency on the microenvironment. Several approaches are utilized to overcome this issue, such as co-culture of CLL cells with other cell types, supplementing culture media with growth factors, or setting up a three-dimensional (3D) culture. Previous studies have shown that 3D cultures, compared to conventional ones, can lead to enhanced cell survival and altered gene expression. 3D cultures can also give valuable information while testing treatment response in vitro since they mimic the cell spatial organization more accurately than conventional culture. Methods: In our study, we investigated the behavior of CLL cells in two types of material: (i) solid porous collagen scaffolds and (ii) gel composed of carboxymethyl cellulose and polyethylene glycol (CMC-PEG). We studied CLL cells' distribution, morphology, and viability in these materials by a transmitted-light and confocal microscopy. We also measured the metabolic activity of cultured cells. Additionally, the expression levels of MYC, VCAM1, MCL1, CXCR4, and CCL4 genes in CLL cells were studied by qPCR to observe whether our novel culture approaches lead to increased adhesion, lower apoptotic rates, or activation of cell signaling in relation to the enhanced contact with co-cultured cells. Results: Both materials were biocompatible, translucent, and permeable, as assessed by metabolic assays, cell staining, and microscopy. While collagen scaffolds featured easy manipulation, washability, transferability, and biodegradability, CMC-PEG was advantageous for its easy preparation process and low variability in the number of accommodated cells. Both materials promoted cell-to-cell and cell-to-matrix interactions due to the scaffold structure and generation of cell aggregates. The metabolic activity of CLL cells cultured in CMC-PEG gel was similar to or higher than in conventional culture. Compared to the conventional culture, there was (i) a lower expression of VCAM1 in both materials, (ii) a higher expression of CCL4 in collagen scaffolds, and (iii) a lower expression of CXCR4 and MCL1 (transcript variant 2) in collagen scaffolds, while it was higher in a CMC-PEG gel. Hence, culture in the material can suppress the expression of a pro-apoptotic gene ( MCL1 in collagen scaffolds) or replicate certain gene expression patterns attributed to CLL cells in lymphoid organs (low CXCR4, high CCL4 in collagen scaffolds) or blood (high CXCR4 in CMC-PEG).
Robust acute myeloid leukemia engraftment in humanized scaffolds using injectable biomaterials and intravenous xenotransplantation
(2025-05-22) Buša, Daniel; Herůdková, Zdenka; Hýl, Jan; Vlažný, Jakub; Sokol, Filip; Matulová, Květoslava; Folta, Adam; Hynšt, Jakub; Vojtová, Lucy; Křen, Leoš; Repko, Martin; Ráčil, Zdeněk; Mayer, Jiří; Čulen, Martin
Patient-derived xenografts (PDXs) can be improved by implantation of a humanized niche. Nevertheless, the overall complexity of the current protocols, as well as the use of specific biomaterials and procedures, limits the wider adoption of this approach. Here, we identify the essential minimum steps required to create the humanized scaffolds and achieve successful acute myeloid leukemia (AML) engraftment. We compared seven biomaterials, which included both published and custom-designed materials. The highest level of bone marrow niche was achieved with extracellular matrix gels and custom collagen fiber, both of which allowed for a simple non-surgical implantation. The biomaterial selection did not influence the following AML infiltration. Regarding xenotransplantation, standard intravenous administration produced the most robust engraftment, even for two out of four otherwise non-engrafting AML samples. In contrast, direct intra-scaffold xenotransplantation did not offer any advantage. In summary, we demonstrate that the combination of an injectable biomaterial for scaffold creation plus an intravenous route for AML xenotransplantation provide the most convenient and robust approach to produce AML PDX using a humanized niche.

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