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Bone tissue engineering is a promising alternative to repair wounds caused by cellular or physical accidents that humans face daily. In this sense, the search for new graphene oxide (GO) nanofillers related to their degree of oxidation is born as an alternative bioactive component in forming new scaffolds. In the present study, three different GOs were synthesized with varying degrees of oxidation and studied chemically and tissue-wise. The oxidation degree was determined through infrared (FTIR), X-ray diffraction (XRD), X-ray photoelectron (XPS), and Raman spectroscopy (RS). The morphology of the samples was analyzed using scanning electron microscopy (SEM). The oxygen content was deeply described using the deconvolution of RS and XPS techniques. The latter represents the oxidation degree for each of the samples and the formation of new bonds promoted by the graphitization of the material. In the RS, two characteristic bands were observed according to the degree of oxidation and the degree of graphitization of the material represented in bands D and G with different relative intensities, suggesting that the samples have different crystallite sizes. This size was described using the Tuinstra-Koenig model, ranging between 18.7 and 25.1 nm. Finally, the bone neoformation observed in the cranial defects of critical size indicates that the F1 and F2 samples, besides being compatible and resorbable, acted as a bridge for bone healing through regeneration. This promoted healing by restoring bone and tissue structure without triggering a strong immune response.

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Cancer stands as one of the deadliest diseases in human history, marked by an inferior prognosis. While traditional therapeutic methods like surgery, chemotherapy, and radiation have demonstrated success in inhibiting tumor cell growth, their side effects often limit overall benefits and patient acceptance. In this regard, three different graphene oxides (GO) with variations in their degrees of oxidation were studied chemically and tissue-wise. The accuracy of the synthesis of the different GO was verified by robust techniques using X-ray photoelectron spectroscopy (XPS), as well as conventional techniques such as infrared spectroscopy (FTIR), RAMAN spectroscopy, and X-ray diffraction (XRD). The presence of oxygenated groups was of great importance. It affected the physicochemical properties of each of the different graphene oxides demonstrated in the presence of new vibrational modes related to the formation of new bonds promoted by the graphitization of the materials. The toxicity analysis in the Hep-2 cell line of graphene oxide formulations at 250 µg/mL on the viability and proliferation of these tumor cells showed low activity. GO formulations did not show high antibacterial activity against Staphylococcus aureus and Escherichia coli strains. However, the different graphene oxides showed biocompatibility in the subdermal implantation model for 30, 60, and 90 days in the biomodels. This allowed healing by restoring hair and tissue architecture without triggering an aggressive immune response.

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The increasing demand for non-invasive biocompatible materials in biomedical applications, driven by accidents and diseases like cancer, has led to the development of sustainable biomaterials. Here, we report the synthesis of four block formulations using polycaprolactone (PCL), polylactic acid (PLA), and zinc oxide nanoparticles (ZnO-NPs) for subdermal tissue regeneration. Characterization by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) confirmed the composition of the composites. Additionally, the interaction of ZnO-NPs mainly occurred with the C=O groups of PCL occurring at 1724 cm-1, which disappears for F4, as evidenced in the FT-IR analysis. Likewise, this interaction evidenced the decrease in the crystallinity of the composites as they act as crosslinking points between the polymer backbones, inducing gaps between them and weakening the strength of the intermolecular bonds. Thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyses confirmed that the ZnO-NPs bind to the carbonyl groups of the polymer, acting as weak points in the polymer backbone from where the different fragmentations occur. Scanning electron microscopy (SEM) showed that the increase in ZnO-NPs facilitated a more compact surface due to the excellent dispersion and homogeneous accumulation between the polymeric chains, facilitating this morphology. The in vivo studies using the nanocomposites demonstrated the degradation/resorption of the blocks in a ZnO-NP-dependant mode. After degradation, collagen fibers (Type I), blood vessels, and inflammatory cells continue the resorption of the implanted material. The results reported here demonstrate the relevance and potential impact of the ZnO-NP-based scaffolds in soft tissue regeneration.

RESUMO

This research focused on developing new materials for endodontic treatments to restore tissues affected by infectious or inflammatory processes. Three materials were studied, namely tricalcium phosphate ß-hydroxyapatite (ß-TCP), commercial and natural hydroxyapatite (HA), and chitosan (CS), in different proportions. The chemical characterization using infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the composition of the composite. Scanning electron microscopy (SEM) demonstrated that the design and origin of the HA, whether natural or commercial, did not affect the morphology of the composites. In vitro studies using Artemia salina (A. salina) indicated that all three experimental materials were biocompatible after 24 h, with no significant differences in mortality rate observed among the groups. The subdermal implantation of the materials in block form exhibited biocompatibility and biodegradability after 30 and 60 days, with the larger particles undergoing fragmentation and connective tissue formation consisting of collagen type III fibers, blood vessels, and inflammatory cells. The implanted material continued to undergo resorption during this process. The results obtained in this research contribute to developing endodontic technologies for tissue recovery and regeneration.

RESUMO

Tissue accidents provide numerous pathways for pathogens to invade and flourish, causing additional harm to the host tissue while impeding its natural healing and regeneration. Essential oils (EOs) exhibit rapid and effective antimicrobial properties without promoting bacterial resistance. Clove oils (CEO) demonstrate robust antimicrobial activity against different pathogens. Chitosan (CS) is a natural, partially deacetylated polyamine widely recognized for its vast antimicrobial capacity. In this study, we present the synthesis of four membrane formulations utilizing CS, polyvinyl alcohol (PVA), and glycerol (Gly) incorporated with CEO and nanobioglass (n-BGs) for applications in subdermal tissue regeneration. Our analysis of the membranes' thermal stability and chemical composition provided strong evidence for successfully blending polymers with the entrapment of the essential oil. The incorporation of the CEO in the composite was evidenced by the increase in the intensity of the band of C-O-C in the FTIR; furthermore, the increase in diffraction peaks, as well as the broadening, provide evidence that the introduction of CEO perturbed the crystal structure. The morphological examination conducted using scanning electron microscopy (SEM) revealed that the incorporation of CEO resulted in smooth surfaces, in contrast to the porous morphologies observed with the n-BGs. A histological examination of the implanted membranes demonstrated their biocompatibility and biodegradability, particularly after a 60-day implantation period. The degradation process of more extensive membranes involved connective tissue composed of type III collagen fibers, blood vessels, and inflammatory cells, which supported the reabsorption of the composite membranes, evidencing the material's biocompatibility.

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The use of biopolymers for tissue engineering has recently gained attention due to the need for safer and highly compatible materials. Starch is one of the most used biopolymers for membrane preparation. However, incorporating other polymers into starch membranes introduces improvements, such as better thermal and mechanical resistance and increased water affinity, as we reported in our previous work. There are few reports in the literature on the biocompatibility of starch/chicken gelatin composites. We assessed the in vivo biocompatibility of the five composites (T1-T5) cassava starch/gelatin membranes with subdermal implantations in biomodels at 30, 60, and 90 days. The FT-IR spectroscopy analysis demonstrated the main functional groups for starch and chicken gelatin. At the same time, the thermal study exhibited an increase in thermal resistance for T3 and T4, with a remaining mass (~15 wt.%) at 800 °C. The microstructure analysis for the T2-T4 demonstrated evident roughness changes with porosity presence due to starch and gelatin mixture. The decrease in the starch content in the composites also decreased the gelatinization heats for T3 and T4 (195.67, 196.40 J/g, respectively). Finally, the implantation results demonstrated that the formulations exhibited differences in the degradation and resorption capacities according to the starch content, which is easily degraded by amylases. However, the histological results showed that the samples demonstrated almost complete reabsorption without a severe immune response, indicating a high in vivo biocompatibility. These results show that the cassava starch/chicken gelatin composites are promising membrane materials for tissue engineering applications.

RESUMO

Scaffolds based on biopolymers and nanomaterials with appropriate mechanical properties and high biocompatibility are desirable in tissue engineering. Therefore, polylactic acid (PLA) nanocomposites were prepared with ceramic nanobioglass (PLA/n-BGs) at 5 and 10 wt.%. Bioglass nanoparticles (n-BGs) were prepared using a sol-gel methodology with a size of ca. 24.87 ± 6.26 nm. In addition, they showed the ability to inhibit bacteria such as Escherichia coli (ATCC 11775), Vibrio parahaemolyticus (ATCC 17802), Staphylococcus aureus subsp. aureus (ATCC 55804), and Bacillus cereus (ATCC 13061) at concentrations of 20 w/v%. The analysis of the nanocomposite microstructures exhibited a heterogeneous sponge-like morphology. The mechanical properties showed that the addition of 5 wt.% n-BG increased the elastic modulus of PLA by ca. 91.3% (from 1.49 ± 0.44 to 2.85 ± 0.99 MPa) and influenced the resorption capacity, as shown by histological analyses in biomodels. The incorporation of n-BGs decreased the PLA crystallinity (from 7.1% to 4.98%) and increased the glass transition temperature (Tg) from 53 °C to 63 °C. In addition, the n-BGs increased the thermal stability due to the nanoparticle's intercalation between the polymeric chains and the reduction in their movement. The histological implantation of the nanocomposites and the cell viability with HeLa cells higher than 80% demonstrated their biocompatibility character with a greater resorption capacity than PLA. These results show the potential of PLA/n-BGs nanocomposites for biomedical applications, especially for long healing processes such as bone tissue repair and avoiding microbial contamination.

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The indiscriminate use of plastic in food packaging contributes significantly to environmental pollution, promoting the search for more eco-friendly alternatives for the food industry. This work studied five formulations (T1-T5) of biodegradable cassava starch/gelatin films. The results showed the presence of the starch/gelatin functional groups by FT-IR spectroscopy. Differential scanning calorimetry (DSC) showed a thermal reinforcement after increasing the amount of gelatin in the formulations, which increased the crystallization temperature (Tc) from 190 °C for the starch-only film (T1) to 206 °C for the film with 50/50 starch/gelatin (T3). It also exhibited a homogeneous surface morphology, as evidenced by scanning electron microscopy (SEM). However, an excess of gelatin showed low compatibility with starch in the 25/75 starch/gelatin film (T4), evidenced by the low Tc definition and very rough and fractured surface morphology. Increasing gelatin ratio also significantly increased the strain (from 2.9 ± 0.5% for T1 to 285.1 ± 10.0% for T5) while decreasing the tensile strength (from 14.6 ± 0.5 MPa for T1 to 1.5 ± 0.3 MPa for T5). Water vapor permeability (WVP) increased, and water solubility (WS) also decreased with gelatin mass rising in the composites. On the other hand, opacity did not vary significantly due to the films' cassava starch and gelatin ratio. Finally, optimizing the mechanical and water barrier properties resulted in a mass ratio of 53/47 cassava starch/gelatin as the most appropriate for their application in food packaging, indicating their usefulness in the food-packaging industry.

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The search for new biocompatible materials that can replace invasive materials in biomedical applications has increased due to the great demand derived from accidents and diseases such as cancer in various tissues. In this sense, four formulations based on polycaprolactone (PCL) and polylactic acid (PLA) incorporated with zinc oxide nanoparticles (ZnO-NPs) and tea tree essential oil (TTEO) were prepared. The sol-gel method was used for zinc oxide nanoparticle synthesis with an average size of 11 ± 2 nm and spherical morphology. On the other hand, Fourier Transformed infrared spectroscopy (FTIR) showed characteristic functional groups for each composite component. The TTEO incorporation in the formulations was related to the increased intensity of the C-O-C band. The thermal properties of the materials show that the degradative properties of the ZnO-NPs decrease the thermal stability. The morphological study by scanning electron microscopy (SEM) showed that the presence of TTEO and ZnO-NPs act synergistically, obtaining smooth surfaces, whereas membranes with the presence of ZnO-NPs or TTEO only show porous morphologies. Histological implantation of the membranes showed biocompatibility and biodegradability after 60 days of implantation. This degradation occurs through the fragmentation of the larger particles with the presence of connective tissue constituted by type III collagen fibers, blood vessels, and inflammatory cells, where the process of resorption of the implanted material continues.

RESUMO

The development of scaffolds for cell regeneration has increased because they must have adequate biocompatibility and mechanical properties to be applied in tissue engineering. In this sense, incorporating nanofillers or essential oils has allowed new architectures to promote cell proliferation and regeneration of new tissue. With this goal, we prepared four membranes based on polylactic acid (PLA), polycaprolactone (PCL), titanium dioxide nanoparticles (TiO2-NPs), and orange essential oil (OEO) by the drop-casting method. The preparation of TiO2-NPs followed the sol-gel process with spherical morphology and an average size of 13.39 nm ± 2.28 nm. The results show how the TiO2-NP properties predominate over the crystallization processes, reflected in the decreasing crystallinity percentage from 5.2% to 0.6% in the membranes. On the other hand, when OEO and TiO2-NPs are introduced into a membrane, they act synergistically due to the inclusion of highly conjugated thermostable molecules and the thermal properties of TiO2-NPs. Finally, incorporating OEO and TiO2-NPs promotes tissue regeneration due to the decrease in inflammatory infiltrate and the appearance of connective tissue. These results demonstrate the great potential for biomedical applications of the membranes prepared.