Journal of Materials Science: Materials in Medicine最新文献

Pyrophyllite is the least studied natural clay in terms of its potential in biomedical applications, although there are many deposits of this aluminosilicate around the world. Genotoxicity study was performed in vitro for this mineral. Subsequently, Wister rats were exposed to the pyrophyllite micronized to below 100 µm. After the exposure period, histology of the lung, liver, kidney and gastric tissues were performed, followed by the stereological and hematological analysis. The physicochemical analyses revealed typical XRD characteristics of pyrophyllite clay with particle-size distribution ranging 50 nm–100 μm with stable mineral composition and unique buffering property to pH around 8. The results showed that there were no cytotoxic effects on to THP-1 cells, or genotoxicity of pyrophyllite measured by the Comet assay. In vivo studies are accompanied by the thorough physicochemical characterization of the micronized pyrophyllite. Histology of the lung tissue proved presence of an inflammatory reaction. On the other hand, gastric tissue has shown the selective accumulation of nanoparticles in enterocytes of the stomach only, as supported by ultrastructural analysis. Liver and kidney tissues have shown tolerability for pyrophyllite particles. The results give directions for further comprehensive studies of potential biomedical applications of the pyrophyllite.

Aim: This study aimed to comprehensively assess the biocompatibility and toxicity profiles of poly(methyl methacrylate) (PMMA) and its monomeric unit, methyl methacrylate (MMA), crucial components in dental materials for interim prosthetic restorations. Methodology: Molecular docking was employed to predict the binding affinities, energetics, and steric features of MMA and PMMA with selected receptors involved in bone metabolism and tissue development, including RANKL, Fibronectin, BMP9, NOTCH2, and other related receptors. The HADDOCK standalone version was utilized for docking calculations, employing a Lamarckian genetic algorithm to explore the conformational space of ligand-receptor interactions. Furthermore, molecular dynamics (MD) simulations over 100 nanoseconds were conducted using the GROMACS package to evaluate dynamic actions and structural stability. The LigandScout was utilized for pharmacophore modeling, which employs a shape-based screening approach to identify potential ligand binding sites on protein targets. Results: The molecular docking studies elucidated promising interactions between PMMA and MMA with key biomolecular targets relevant to dental applications. MD simulation results provided strong evidence supporting the structural stability of PMMA complexes over time. Pharmacophore modeling highlighted the significance of carbonyl and hydroxyl groups as pharmacophoric features, indicating compounds with favorable biocompatibility profiles. Conclusion: This study underscores the potential of PMMA in dental applications, emphasizing its structural stability, molecular interactions, and safety considerations. These findings lay a foundation for future advancements in dental biomaterials, guiding the design and optimization of materials for enhanced biocompatibility. Future directions include experimental validation of computational findings and the development of PMMA-based dental materials with improved biocompatibility and clinical performance.

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Objective: Aortic valve neocuspidization (AVNeo) using autologous pericardium is a promising technique. Expected advantages are reduced immune response, appropriate biomechanics and lower treatment expenses. Nevertheless, autologous pericardium can be affected by patient’s age and comorbidities. Usually, glutaraldehyde (GA) - fixed bovine pericardium is the basic material for aortic valve prostheses, easy available and carefully pre-examined in a standardized fabrication process. Aim of the study is the verification of autologous pericardial tissue homogeneity by analysing tissue thickness, biomechanics and extracellular matrix (ECM) composition. Methods: Segments of human GA-fixed pericardium selected by the surgeon based on visual criteria for cusp pre-cut and remaining after surgical AV replacement were investigated in comparison to bovine standard tissue treated equivalently. Pericardium sampling was performed at up to three positions of each sutured cusp for histological or biomechanical analysis, according to tissue availability. Results and Conclusions: Human pericardia exhibited a higher heterogeneity in collagen content, density of vessel structures and elastic moduli. Thickness, vessel density and collagen and elastin content differed significantly between the species. In contrast, significant interindividual differences were detected in most properties investigated for human pericardial samples but only for tissue thickness in bovine tissues. Higher heterogeneity of human pericardium, differing vessel and collagen content compared to bovine state-of-the-art material might be detrimental for long term AV functionality or deterioration and have to be intensely investigated in patients follow up after autologous cusp replacement.

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Bioactive, nanoporous TiO₂-coating has been shown to enhance cell attachment on titanium implant surface. The aim of this study was to evaluate, whether the saliva proteins affect the epithelial cell adhesion on TiO₂-coated and non-coated titanium. Grade V titanium discs were polished. Half of the discs were provided with TiO₂-coating produced in sol with polycondensation method. Half of the TiO₂-coated and non-coated discs were treated with pasteurized saliva for 30 min. After saliva treatment, the total protein amounts on surfaces were measured. Next, the hydrophilicity of discs were measured with water contact angle measurements. Further, the gingival keratinocyte adhesion strength was measured after 2 and 6 h of cultivation using serial trypsinization. In addition, cell growth and proliferation were measured after 1, 3, and 7 days of cell culture. Finally, cell morphology, spreading and adhesion protein signals were detected with high resolution confocal microscopy. As a result, in sol coated TiO₂-surface had significantly higher hydrophilicity when compared to non-coated titanium, meanwhile both non-coated and TiO₂-coated surfaces with saliva treatment had a significant increase in hydrophilicity. Importantly, the amounts of adhered saliva proteins were equal between TiO₂-coated and non-coated surfaces. Adhesion strength against enzymatic detachment was weakest on non-coated titanium after saliva exposure. Cell proliferation and cell spreading were highest on TiO₂-coated titanium, but saliva exposure significantly decreased cell proliferation and spreading on TiO₂-coated surface. To conclude, even though saliva exposure makes titanium surfaces more hydrophilic, it seems to neutralize the bioactive TiO₂-coating and decrease cell attachment to TiO₂-coated surface.

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Surface modification of titanium and its alloys has been seriously considered by researchers to improve their biological behaviors, in the past few decades. In present research, hydroxyapatite (HA) based composite coatings with different concentrations of 0, 2, 4, and 6 wt% of silver (Ag) nanoparticles were electrophoretically deposited (EPD) on anodized and non-anodized Ti6Al4V, using a direct current at a voltage of 30 V for 10 min at room temperature. The specimens were then characterized by means of X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). The cell adhesion images and cell viability results showed that HA-Ag composite coatings significantly promoted the biocompatibility of samples compared with the non-anodized and anodized Ti6Al4V. The viabilities of Mg-63 cells on HA-4%Ag coating and bi-layer coating (HA-4%Ag on anodized specimen) were approximately 91% and they were considered as the best coatings in term of biocompatibility. On the other hand, the antibacterial assessments demonstrated that HA-6%Ag coating had the best antibacterial performance compared with other samples. Furthermore, Tafel polarization curves indicated that corrosion resistance of the bi-layer coating was higher than those of the other specimens. The polarization resistance of this coating was about 7 times more than that of theTi6Al4V alloy.

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In the aging society, slow bone regeneration poses a serious hindrance to the quality of life. To deal with this problem, in this study, we have combined irisin with the bioglass regular beads to enhance the bone regeneration process. For this purpose, highly porous bioglass was obtained as spherical beads by using sodium alginate. The bioglass was evaluated by various analytical techniques such as SEM, EDS, XRD, and pore size distribution. The results depicted that porous bioglass was prepared correctly and SEM analysis showed a highly porous bioglass was formulated. On this bioglass, irisin was loaded with the assistance of polyvinyl alcohol (PVA) in three concentrations (50 ng/ml, 100 ng/ml, and 150 ng/ml per 1 g of bioglass). SEM analysis showed that pores are covered with PVA. The irisin release profile showed a sustained release over the time period of 7 days. In vitro, biocompatibility evaluation by the MC3T3E1 cells showed that prepared bioglass and irisin loaded bioglass (BGI50, BGI100, and BG150) are highly biocompatible. Alizarin Red staining analysis showed that after 2 weeks BGI50 samples showed highest calcium nodule formation. In vivo in the rabbit femur model was conducted for 1 and 2 months. BGI150 samples showed highest BV/TV ratio of 37.1 after 2 months. The histological data showed new bone formation surrounding the beads and with beads loaded with irisin. Immunohistochemistry using markers OPN, RUNX, COL, and ALP supported the osteogenic properties of the irisin-loaded bioglass beads. The results indicated that irisin-loaded bioglass displayed remarkable bone regeneration.

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The efficacy of stem-cell therapy depends on the ability of the transplanted cells to escape early immunological reactions and to be retained at the site of transplantation. The use of tissue engineering scaffolds or injectable biomaterials as carriers has been proposed, but they still present limitations linked to a reliable manufacturing process, surgical practice and clinical outcomes. Alginate microbeads are potential candidates for the encapsulation of mesenchymal stromal cells with the aim of providing a delivery carrier suitable for minimally-invasive and scaffold-free transplantation, tissue-adhesive properties and protection from the immune response. However, the formation of stable microbeads relies on the cross-linking of alginate with divalent calcium ions at concentrations that are toxic for the cells, making control over the beads’ size and a single-cell encapsulation unreliable. The present work demonstrates the efficiency of an innovative, high throughput, and reproducible microfluidic system to produce single-cell, calcium-free alginate coatings of human mesenchymal stromal cells. Among the various conditions tested, visible light and confocal microscopy following staining of the cell nuclei by DAPI showed that the microfluidic system yielded an optimal single-cell encapsulation of 2000 cells/min in 2% w/v alginate microcapsules of reproducible morphology and an average size of 28.2 ± 3.7 µm. The adhesive properties of the alginate microcapsules, the viability of the encapsulated cells and their ability to escape the alginate microcapsule were demonstrated by the relatively rapid adherence of the beads onto tissue culture plastic and the cells’ ability to gradually disrupt the microcapsule shell after 24 h and proliferate. To mimic the early inflammatory response upon transplantation, the encapsulated cells were exposed to proliferating macrophages at different cell seeding densities for up to 2 days and the protection effect of the microcapsule on the cells assessed by time-lapse microscopy showing a shielding effect for up to 48 h. This work underscores the potential of microfluidic systems to precisely encapsulate cells by good manufacturing practice standards while favouring cell retention on substrates, viability and proliferation upon transplantation.

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Xyloglucan is a rigid polysaccharide that belongs to the carbohydrate family. This hemicellulose compound has been widely used in biomedical research because of its pseudoplastic, mucoadhesive, mucomimetic, and biocompatibility properties. Xyloglucan is a polyose with no amino groups in its structure, which also limits its range of applications. It is still unknown whether grafting hydrophilic monomers onto xyloglucan can produce derivatives that overcome these shortcomings. This work aimed to prepare the first copolymers in which N-hydroxyethyl acrylamide is grafted onto tamarind xyloglucan by free-radical polymerization. The biocompatibility of these structures in vitro was evaluated using human dermal fibroblasts. Gamma radiation-induced graft polymerization was employed as an initiator by varying the radiation dose from 5–25 kGy. The structure of the graft copolymer, Xy-g-poly(N-hydroxyethyl acrylamide), was verified by thermal analysis, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The findings indicate that the degree of grafting and the cytotoxicity/viability of the xyloglucan-based copolymer were independent of dose. Notably, the grafted galactoxyloglucan exhibited efficient support for human dermal fibroblasts, showing heightened proliferative capacity and superior migration capabilities compared to the unmodified polymer. This copolymer might have the potential to be used in skin tissue engineering.

Biodegradable porous Mg scaffolds are a promising approach to bone repair. In this work, 3D-spherical porous Mg–1.5Zn–0.2Ca (wt.%) scaffolds were prepared by vacuum infiltration casting technology, and MgF₂ and fluorapatite coatings were designed to control the degradation behavior of Mg-based scaffolds. The results showed that the pores in Mg-based scaffolds were composed of the main spherical pores (450–600 μm) and interconnected pores (150–200 μm), and the porosity was up to 74.97%. Mg-based porous scaffolds exhibited sufficient mechanical properties with a compressive yield strength of about 4.04 MPa and elastic modulus of appropriately 0.23 GPa. Besides, both MgF₂ coating and fluorapatite coating could effectively improve the corrosion resistance of porous Mg-based scaffolds. In conclusion, this research would provide data support and theoretical guidance for the application of biodegradable porous Mg-based scaffolds in bone tissue engineering.

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