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Scaffolds are devices with interconnected pores that favor cell interaction and proliferation. They play a significant role in tissue engineering, as they mimic the conditions of tissue production in vivo. The aim of this study was to synthesize scaffolds of chitosan, collagen, and Jatropha mollissima by lyophilization and characterize their chemical/biodegradability and morphological properties. For that, techniques of optical microscopy, infrared spectrometry, biodegradation test, and degree of swelling were performed. A 2% (m/v) chitosan/collagen (1:9) in lactic acid solution was produced. Then, Jatropha mollissima crude extract was added to this solution in different proportions of mass (5, 10, and 15%). Optical microscope images indicated the three-dimensional network formation with interconnected pores and predominantly lamellar shape. Through infrared spectrometry, characteristic bands indicated a physical mixture. Also, the swelling degree of all samples was proportional to the amount of Jatropha mollissima extract with the highest percentage of 1852%. Biodegradation test also revealed a proportional ratio between the amount of sap used and the degraded percentage with the lowest value of around 35% in 28 days. In conclusion, it can be inferred that the scaffolds produced show potential to be used in tissue engineering as dressings.

Due to the physical, thermal, and biological properties of silver nanoparticles (AgNPs), as well as the biocompatibility and environmental safety of the naturally occurring polymeric component, polysaccharide-based composites containing AgNPs are a promising choice for the development of biomaterials. Starch is a low-cost, non-toxic, biocompatible, and tissue-healing natural polymer. The application of starch in various forms and its combination with metallic nanoparticles have contributed to the advancement of biomaterials. Few investigations into jackfruit starch with silver nanoparticle biocomposites exist. This research intends to explore the physicochemical, morphological, and cytotoxic properties of a Brazilian jackfruit starch-based scaffold loaded with AgNPs. The AgNPs were synthesized by chemical reduction and the scaffold was produced by gelatinization. X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), and Fourier-transform infrared spectroscopy (FTIR) were used to study the scaffold. The findings supported the development of stable, monodispersed, and triangular AgNPs. XRD and EDS analyses demonstrated the incorporation of silver nanoparticles. AgNPs could alter the scaffold’s crystallinity, roughness, and thermal stability without affecting its chemistry or physics. Triangular anisotropic AgNPs exhibited no toxicity against L929 cells at concentrations ranging from 6.25 × 10−5 to 1 × 10−3 mol·L−1, implying that the scaffolds might have had no adverse effects on the cells. The scaffolds prepared with jackfruit starch showed greater crystallinity and thermal stability, and absence of toxicity after the incorporation of triangular AgNPs. These findings indicate that jackfruit is a promising starch source for developing biomaterials.

This study aimed to achieve bioactivity on the PEEK surface using piranha solution through a lower functionalization time. For this purpose, the functionalization occurred with piranha solution and 98% sulfuric acid in the proportions of 1:2, 1:1, and 2:1 at periods of 30, 60, and 90 s. The samples treated for longer times at higher concentrations registered the characteristic spectroscopy band associated with sulfonation. Additionally, both chemical treatments allowed the opening of the aromatic ring, increasing the number of functional groups available and making the surface more hydrophilic. The piranha solution treatments with higher concentrations and longer times promoted greater heterogeneity in the surface pores, which affected the roughness of untreated PEEK. Furthermore, the treatments induced calcium deposition on the surface during immersion in SBF fluid. In conclusion, the proposed chemical modifications using sulfuric acid SPEEK 90 and, especially, the piranha solution PEEK-PS 2:1-90, were demonstrated to be promising in promoting the rapid bioactivation of PEEK-based implants.

This work aimed to develop and evaluate the influence of processing variables on the morphology and swelling of sulfonated poly(ether ether ketone) (SPEEK) spheres for possible applications as a biomaterial. We used the drip method to obtain spheres with the polymer starting solutions SPEEK-6 (w/v: 6%) and SPEEK-10 (w/v: 10%), drip rates (20 and 30 mL/h), and drip heights (5 and 10 cm) in experimental planning. The samples were characterized by Fourier-transform infrared spectroscopy (FTIR), optical microscopy (OM), the absorption capacity of phosphate-buffered saline (PBS) by swelling (%), and statistical analysis of data through Design of Experiments (DOE). The obtained results evidenced that the processing variables influenced the morphology and swelling. Spheres with a bigger concentration of the polymer solution presented a greater degree of sulfonation (DS). We verified that the diameter of the spheres was directly related to the variable height and the sphericity was associated with the speed and viscosity of the solution. Bigger and more pores in a greater amount were observed in the spheres with a greater DS, influencing the behavior of the swelling in PBS. The better variable combinations with a high DS, regular sphericity, a smaller diameter, and greater swelling were the samples S2-10-20-5 e S10-10-20-5. The cytotoxicity indicated that the best samples obtained in the experimental planning (S2-10-20-5 and S10-10-20-5) were not toxic. In that regard, the evaluated spheres presented cell viability and swelling capacity, suggesting their possible applications as biomaterials.

Abstract The aim of this study was to evaluate the degree of conversion (DC) and the thermal stability of bulk-fill and conventional composite resins. Eleven composite resin samples were prepared to evaluate the DC, Vickers microhardness (VMH), mass and residue/particle loss, glass transition temperature (Tg), enthalpy, and linear coefficient of thermal expansion (CTE) using infrared spectroscopy (FTIR), microdurometer analyses, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dilatometry (DIL). The data were subjected to statistical analysis, with a significance level of 95%. DC and VMH were not influenced by the polymerized side of the sample, and statistical differences were recorded only among the materials. Decomposition temperature, melting, and mass and residue loss were dependent on the material and on the evaluation condition (polymerized and non-polymerized). Tg values were similar between the composites, without statistically significant difference, and CTE ranged from 10.5 to 37.1 (10-6/°C), with no statistical difference between the materials. There was a moderate negative correlation between CTE and the % of load particles, by weight. Most resins had a DC above that which is reported in the literature. TGA, Tg, and CTE analyses showed the thermal behavior of the evaluated composites, providing data for future research, assisting with the choice of material for direct or semidirect restorations, and helping choose the appropriate temperature for increasing the DC of such materials.

Abstract Poly(ether ether ketone) (PEEK) has excellent properties, such as high biocompatibility and an elastic modulus similar to bone, which makes it a suitable biomaterial. When modified with sulfuric acid (H2SO4) and hydroxyapatite (HA), its workability and bioactivity is enhanced, and this makes it of great importance in medicine. This study investigates a better combination of process parameters to manufacture sulfonated PEEK/HA (SPEEK/HA) membranes for biomaterials. Chemical, thermal, and biological analyses were carried out on all samples. The sulfonated structure was observed to enhance wettability, adhesion, and cell viability. Furthermore, an increase in the degree of sulfonation facilitated their workability as required for biomaterials; making them suitable for osseointegration. Besides, the SPEEK/HA membranes presented cell adhesion, confirming the viability to use as biomaterial. This study presents a cheap alternative method to easily process biomaterials of improved workability.

Carbonated hydroxyapatite (CHAp) and β-tricalcium phosphate (β-TCP) have been employed for decades as constituents of scaffolds for bone regeneration because they chemically resemble bone mineral. In this study, the feasibility to manufacture CHAp/β-TCP scaffolds by pseudomorphic transformation of casted blocks of gypsum was investigated. The transformation was carried out by immersing the precursor gypsum block in 1 M (NH4)2HPO4/1.33 M NH4OH solution with liquid/solid ratio of 10 mL/g and autoclaving at 120 °C and 203 kPa (2 atm) for 3 h at least. Neither shape nor dimensions significantly changed during transformation. The composition of scaffolds treated for 3 h was 70 wt.% CHAp and 30 wt.% β-TCP, and their compressive and diametral compressive strengths were 6.5 ± 0.7 and 5.3 ± 0.7 MPa, respectively. By increasing the time of treatment to 6 h, the composition of the scaffold enriched in β-TCP (60 wt.% CHAp and 40 wt.% β-TCP) but its compressive and diametral compressive strengths were not significantly affected (6.7 ± 0.9 and 5.4 ± 0.6 MPa, respectively). On the basis of the results obtained, it was concluded that this route is a good approach to the manufacturing of biphasic (CHAp/β-TCP) scaffolds from previously shaped pieces of gypsum.

Nanoparticles of zinc oxide (ZnO) were added to poly( ε -caprolactone) (PCL), and PCL/ZnO casting films were produced, afterwards films were characterized using Fourier Transform Infrared Spectroscopy (FTIR), x-ray Diffraction (XRD), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Additionally, antimicrobial and cytotoxic parameters were determined using microbial adhesion testing according to JIS Z 2801: 2000 (E) and agar diffusion method according to ISO 10993-5 2009 , respectively. From collected data, the chemical identity of individual components was kept and the surface control could be achieved changing the composition. According to FTIR spectra and using the Lambert-Beer law higher interaction ratios were met for higher ZnO content which is linked to antimicrobial action. As revealed by AFM analysis, at 5% of ZnO, nanoparticles were well dispersed in PCL matrix with uniform surface film. Analyses from antibacterial activity and cytotoxicity suggested pathogenic Staphylococcus aureus growth was hindered in ZnO films; specifically for PCL/ZnO 5% optimal antibacterial activity and toxicity absent were reached. Summing up, PCL/ZnO5% nanocomposites films offer great potential for commercial applications as active food packaging.

Abstract The aim of this study was to evaluate the cytotoxic effect, degree of conversion (% DC), Vickers hardness (VH), and surface morphology of composite resins. Eleven resins, nine bulk-fill resins, and two conventional resins were evaluated. Each material was sampled to evaluate DC (using FTIR), VH, cytotoxicity (using MTT and Neutral Red - NR test), surface morphology (using SEM and AFM), and organic filler (using EDS). All statistical tests were performed with SPSS and the level of significance was set at 0.05. MTT revealed that the materials presented low or no cytotoxic potential in relation to the control. Opus was the resin with the lowest cell viability at a 1:2 concentration at 72 h (32%) and at 7 days (43%), but that significantly increased when the NR test was applied at a 1:2 concentration after 7 days. Thickness and surface subjected to polymerization had no influence on DC, and differences were observed only between the materials. In the microhardness test, statistical differences were observed between the evaluated thicknesses. The bulk-fill resins analyzed in this study exhibited low and/or no cytotoxicity to L929 cells, except for Opus, which showed moderate cytotoxicity according to the MTT assay. When the NR test was used, results were not satisfactory for all composites, indicating the need for different methodologies to evaluate the properties of these materials. The assessed resins demonstrated acceptable physicomechanical properties.

The aim of this work was to perform an analysis of the influence of Sodium Fluoride (NaF) on chitosan particles size and morphology produced via ionotropic gelation with higher rotational stirring speed. Samples were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS), Zeta Potential (ζ), Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM/EDS). Chitosan/TPP particles diameter obtained was in the order of 3.8 µm. When NaF was added in different concentration (0.05%, 0.2% and 2%), the particle size diameter values, Zeta Potential and Poly Dispersive Index measures consequently decreased. Even so, no further modification in morphology was found. An exception was made for the samples with higher NaF concentration. After 21 days, occurred an increase in the particle size diameter. In the future, the proposed methodology could provide a dentistry application, especially on delivering particles of NaF.

Several studies have established an association between diabetes and alterations in bone metabolism; however, the underlying mechanism is not well established. Although zinc is recognized as a potential preventive agent against diabetes-induced bone loss, there is no evidence demonstrating its effect in chronic diabetic conditions. This study evaluated the effects of zinc supplementation in a chronic (90 days) type 1 diabetes-induced bone-loss model. Male Wistar rats were distributed in three groups: control, type 1 diabetes mellitus (T1DM), and T1DM plus zinc supplementation (T1DMS). Serum biochemical analysis; tibia histomorphometric, biomechanical, and collagen-content analyses; and femur mRNA expression were evaluated. Relative to T1DM, the zinc-supplemented group showed increased histomorphometric parameters such as TbWi and BAr and decreased TbSp, increased biomechanical parameters (maximum load, stiffness, ultimate strain, and Young's modulus), and increased type I collagen content. Interestingly, similar values for these parameters were observed between the T1DMS and control groups. These results demonstrate the protective effect of zinc on the maintenance of bone strength and flexibility. In addition, downregulation of OPG, COL1A, and MMP-9 genes was observed in T1DMS, and the anabolic effects of zinc were evidenced by increased OC expression and serum ALP activity, both related to osteoblastogenesis, demonstrating a positive effect on bone formation. In contrast, T1DM showed excessive bone loss, observed through reduced histomorphometric and biomechanical parameters, characterizing diabetes-associated bone loss. The bone loss was also observed through upregulation of OPG, COL1A, and MMP-9 genes. In conclusion, zinc showed a positive effect on the maintenance of bone architecture and biomechanical parameters. Indeed, OC upregulation and control of expression of OPG, COL1A, and MMP-9 mRNAs, even in chronic hyperglycemia, support an anabolic and protective effect of zinc under chronic diabetic conditions. Furthermore, these results indicate that zinc supplementation could act as a complementary therapy in chronic T1DM.

Photoprotective cosmetic emulsions have gained significant attention in the cosmetic industry due to their ability to protect against harmful ultraviolet radiation (UV). In this work, photoprotective cosmetic emulsions were prepared by adding 5% natural (Branca and Verde Inferior) and commercial (Brasgel and Cloisite) Brazilian clays to different photoprotective emulsions with and without UVA and UVB chemical filters (EB, EB1 and EB2). All clays were benefited (crushed, milled and sieved) and characterized (X ray fluorescence and X ray diffraction). Additionally, a thermal treatment (120 °C by 24 h) was accomplished in the natural clays, aimed at decontamination. The emulsions were characterized for their organoleptic properties, centrifugation test, viscous behavior, pH values and in vitro sun protection factor (SPF). The cosmetic emulsions prepared without any addition of UV chemical filters presented the lowest in vitro and UVB absorption values because the clays used (Cloisite and Branca) did not have the potential to absorb UV radiation. Although some of the cosmetic emulsions prepared from EB1 and EB2 photoprotective emulsions presented phase separation, all of them presented in vitro SPF values according to the Brazilian standard (above 6), indicating that they have the potential to be used in the cosmetic industry. [ABSTRACT FROM AUTHOR]

Background: It is known that some sectors of hospitals have high bacteria and virus loads that can remain as aerosols in the air and represent a significant health threat for patients and mainly professionals that work in the place daily. Therefore, the need for a respirator able to improve the filtration barrier of N95 masks and even inactivating airborne virus and bacteria becomes apparent. Such a fact motivated the creation of a new N95 respirator which employs chitosan nanoparticles on its intermediate layer (SN95 + CNP). Results: The average chitosan nanoparticle size obtained was 165.20 ± 35.00 nm, with a polydispersity index of 0.36 ± 0.03 and a zeta potential of 47.50 ± 1.70 mV. Mechanical tests demonstrate that the SN95 + CNP respirator is more resistant and meets the safety requisites of aerosol penetration, resistance to breath and flammability, presenting higher potential to filtrate microbial and viral particles when compared to conventional SN95 respirators. Furthermore, biological in vitro tests on bacteria, fungi and mammalian cell lines (HaCat, Vero E6 and CCL-81) corroborate the hypothesis that our SN95 + CNP respirator presents strong antimicrobial activity and is safe for human use. There was a reduction of 96.83% of the alphacoronavirus virus and 99% of H1N1 virus and MHV-3 betacoronavirus after 120 min of contact compared to the conventional respirator (SN95), demonstrating that SN95 + CNP have a relevant potential as personal protection equipment. Conclusions: Due to chitosan nanotechnology, our novel N95 respirator presents improved mechanical, antimicrobial and antiviral characteristics. [ABSTRACT FROM AUTHOR]

Due to the physical, thermal, and biological properties of silver nanoparticles (AgNPs), as well as the biocompatibility and environmental safety of the naturally occurring polymeric component, polysaccharide-based composites containing AgNPs are a promising choice for the development of biomaterials. Starch is a low-cost, non-toxic, biocompatible, and tissue-healing natural polymer. The application of starch in various forms and its combination with metallic nanoparticles have contributed to the advancement of biomaterials. Few investigations into jackfruit starch with silver nanoparticle biocomposites exist. This research intends to explore the physicochemical, morphological, and cytotoxic properties of a Brazilian jackfruit starch-based scaffold loaded with AgNPs. The AgNPs were synthesized by chemical reduction and the scaffold was produced by gelatinization. X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), and Fourier-transform infrared spectroscopy (FTIR) were used to study the scaffold. The findings supported the development of stable, monodispersed, and triangular AgNPs. XRD and EDS analyses demonstrated the incorporation of silver nanoparticles. AgNPs could alter the scaffold's crystallinity, roughness, and thermal stability without affecting its chemistry or physics. Triangular anisotropic AgNPs exhibited no toxicity against L929 cells at concentrations ranging from 6.25 × 10−5 to 1 × 10−3 mol·L−1, implying that the scaffolds might have had no adverse effects on the cells. The scaffolds prepared with jackfruit starch showed greater crystallinity and thermal stability, and absence of toxicity after the incorporation of triangular AgNPs. These findings indicate that jackfruit is a promising starch source for developing biomaterials. [ABSTRACT FROM AUTHOR]

This study aimed to achieve bioactivity on the PEEK surface using piranha solution through a lower functionalization time. For this purpose, the functionalization occurred with piranha solution and 98% sulfuric acid in the proportions of 1:2, 1:1, and 2:1 at periods of 30, 60, and 90 s. The samples treated for longer times at higher concentrations registered the characteristic spectroscopy band associated with sulfonation. Additionally, both chemical treatments allowed the opening of the aromatic ring, increasing the number of functional groups available and making the surface more hydrophilic. The piranha solution treatments with higher concentrations and longer times promoted greater heterogeneity in the surface pores, which affected the roughness of untreated PEEK. Furthermore, the treatments induced calcium deposition on the surface during immersion in SBF fluid. In conclusion, the proposed chemical modifications using sulfuric acid SPEEK 90 and, especially, the piranha solution PEEK-PS 2:1-90, were demonstrated to be promising in promoting the rapid bioactivation of PEEK-based implants. [ABSTRACT FROM AUTHOR]

There is an ongoing profound shift in using glass as a primarily passive material to one that instills active properties. We believe and demonstrate that bioactive glasses (BGs) and glass–ceramics (BGCs) as functional biomaterials for cancer therapy can transform the world of healthcare in the 21st century. Melt/gel‐derived BGs and BGCs can carry many exotic elements, including less common rare‐earth, and trigger highly efficient anticancer properties via the combination of radiotherapy, photothermal therapy, magnetic hyperthermia, along with drug or therapeutic ions delivery. The addition of these dopants modifies the bioactivity, imparts novel functionalities, and induces specific biological effects that are not achievable using other classes of biomaterials. In this paper, we have briefly reviewed and discussed the current knowledge on promising compositions, processing parameters, and applications of BGs and BGCs in treating cancer. We also envisage the need for further research on this particular, unique class of BGs and BGCs. [ABSTRACT FROM AUTHOR]

Bacterial resistance refers to the ability of bacteria to resist the action of some antibiotics due to the development of adaptation and resistance mechanisms. It is a serious public health problem, especially for diseases caused by opportunistic bacteria. In this context, the search for new drugs, used alone or in combination, appears as an alternative for the treatment of microbial infections, and natural products, such as essential oils, are important in this process due to their structural diversity, which increases the probability for antimicrobial action. The objective of this study was to extract and identify the chemical components of the essential oil from Croton conduplicatus (EOCC), to evaluate the antimicrobial activity, to investigate the effect of the interaction between the EOCC and different antibiotics and to evaluate its antibiofilm potential. The EOCC was obtained by hydrodistillation. Based on chemical characterisation, 70 compounds were identified, with 1.8 cineole (13.15%), p-cymene (10.68%), caryophyllene (9.73%) and spathulenol (6.36%) being the major constituents. The minimum inhibitory concentration (MIC) values of EOCC were 256 and 512 µg mL−1 for methicillin-sensitive and -resistant Staphylococcus aureus strains (MSSA and MRSA), respectively. The combinations of EOCC with the antibiotics oxacillin and ampicillin were synergistic (OXA/EOCC and AMP/EOCC combined decreased the OXA MIC and AMP MIC to 0.5 and 0.25 for MSSA, respectively, and OXA/EOCC and AMP/EOCC combined decreased the OXA MIC and the AMP MIC to 1 and 0.5 for MRSA, respectively) and could modify the resistance profile of MSSA and MRSA strains. The results indicated that EOCC was also able to partially inhibit biofilm formation. Our study presents important information about the chemical composition of EOCC and its antimicrobial potential and provides a reference to determine the mechanisms of action of EOCC and its use in pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bone cements aid in bone regeneration; however, if the handling time is not well established for the material to harden, complications may arise. OBJECTIVE: This work investigates the effect of using polyethylene glycol (PEG) and characterize it in brushite bone cement in order to obtain desirable handling times as well as its regeneration in vivo to analyse if addition of this polymer may significantly modify its properties. METHODS: PEG 4000 was synthesised with wollastonite by phosphorization reaction in order to form brushite which was further cured by oven drying. They were further characterised and tested in vivo as tibial bone defect model using rabbits. RESULTS: Addition of PEG exhibited handling times of 60 min with a low increase in temperature when curing. Brushite phase of ∼71% was obtained after cement hardening with good compressive strength (25 MPa) and decent values of porosity (33%). In vivo presented that, at 40 days postoperatively, accelerated bone neoformation with partial consolidation at 30 days and total after 60 days when using bone cement. CONCLUSIONS: Addition of PEG does not disrupt the beneficial properties of the bone cement and can be a potential alternative to control the time-temperature profile of hardening these materials. [ABSTRACT FROM AUTHOR]

This work aimed to develop and evaluate the influence of processing variables on the morphology and swelling of sulfonated poly(ether ether ketone) (SPEEK) spheres for possible applications as a biomaterial. We used the drip method to obtain spheres with the polymer starting solutions SPEEK-6 (w/v: 6%) and SPEEK-10 (w/v: 10%), drip rates (20 and 30 mL/h), and drip heights (5 and 10 cm) in experimental planning. The samples were characterized by Fourier-transform infrared spectroscopy (FTIR), optical microscopy (OM), the absorption capacity of phosphate-buffered saline (PBS) by swelling (%), and statistical analysis of data through Design of Experiments (DOE). The obtained results evidenced that the processing variables influenced the morphology and swelling. Spheres with a bigger concentration of the polymer solution presented a greater degree of sulfonation (DS). We verified that the diameter of the spheres was directly related to the variable height and the sphericity was associated with the speed and viscosity of the solution. Bigger and more pores in a greater amount were observed in the spheres with a greater DS, influencing the behavior of the swelling in PBS. The better variable combinations with a high DS, regular sphericity, a smaller diameter, and greater swelling were the samples S2-10-20-5 e S10-10-20-5. The cytotoxicity indicated that the best samples obtained in the experimental planning (S2-10-20-5 and S10-10-20-5) were not toxic. In that regard, the evaluated spheres presented cell viability and swelling capacity, suggesting their possible applications as biomaterials. [ABSTRACT FROM AUTHOR]

This paper approaches the synthesis and characterization of pure (45S5) and Ag-doped (45S5-Ag) bioglasses obtained through the sol–gel method and the development of chitosan/45S5-Ag biocomposites, followed by their performance evaluation as biomaterial candidates. The bioglasses were made from the precursors of tetraethyl orthosilicate (TEOS), triethyl phosphate (TEP), calcium nitrate tetrahydrate, and sodium carbonate. Silver nitrate at the concentrations of 5 and 10% was used as the doping agent. The gel production was followed by a drying process at 60 °C for 24 h, and then, heat treatment at 700 °C was carried out for 2 h. Next, the bioglass powders were added to a chitosan solution at the concentration of 80% ww−1. The solutions were lyophilized before and after neutralization. The samples were characterized via TG, DTA, DSC, DRX, FTIR, SEM, OM, biodegradation, cytotoxicity, and antibacterial activity. Through TG, the increase in silver percentage in the bioglass resulted in lower mass loss of biocomposites, while for DSC higher thermal stability of the polymeric phase was observed for the doped samples. The biological assays demonstrate that CB5 and CB10 samples present inhibition activity against gram-positive and gram-negative bacteria. Both CB5 and CB10 can be almost entirely degraded by phosphate-buffered saline in 28 days and are not cytotoxic, which lays bare that these samples can be used for tissue regeneration. [ABSTRACT FROM AUTHOR]

Chitosan has been widely studied for use in different biomaterial applications. The aim of our study was to produce biodegradable threads of chitosan mono- and multifilaments for possible use as sutures by using the wet spinning technique. We obtained the wires by using a chitosan solution at 4%, and aqueous solution of NaOH 1 M as coagulating bath. Optical microscopy and scanning electron microscopy were used. We also compared the mechanical properties of wires with and without the presence of a knot. Our results show that the chitosan wires have a cylindrical morphology and that the multifilament wires are 74.4% larger in diameter compared to monofilament wires. We also show that multifilament wires have a higher tensile strength Finally, we show that chitosan wires hold promise for use as surgical sutures because their mechanical properties are compatible with the U.S. Pharmacopeia specifications for surgical sutures. [ABSTRACT FROM AUTHOR]

Sulfonated poly(ether ether ketone)/hydroxyapatite (SPEEK/HA) composites were fabricated using the proton exchange membrane fuel cell (PEMFC) method, and evaluated as biomaterials. All membranes were characterised by chemical and morphological methods to prove the successful sulfonation and deposition of HA. A porous structure that allows adhesion and cell viability was observed. Thus, the results of the study indicate an alternative method to process biomaterials, with lower cost and easy workability and preparation. [ABSTRACT FROM AUTHOR]

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The objective of this work was to investigate the thermal, morphological, spectroscopic and cytotoxicity of hydroxyapatite-wollastonite powders obtained via sol-gel synthesis and of biocomposites chitosan-hydroxyapatite-wollastonite. A mixture of wollastonite, calcium nitrate tetrahydrate and ammonium dihydrogen phosphate with a ratio of 1:2:1.2 or 2:2:1.2, respectively, was produced following drying and heat treatment where the final composite was macerated. These powders were added to a chitosan solution where it was further dried and neutralized. The ceramic loads were used in various ratios. The materials were characterized by TG, DSC, DRX, MEV, FTIR and cytotoxicity. Based on the studied properties, it can be said that the sol-gel process proved to be effective in obtaining hydroxyapatite-wollastonite powders. By TG, it was verified that the thermal stability of the powders increased when a greater percentage of wollastonite was used. For biocomposites with higher percentages of load, there was increase in thermal stability, probably attributed to the higher compaction of the biocomposites when compared to the pure. By DSC, there was a tendency of displacement of the endothermic and exothermic peaks, suggesting that the biocomposite with higher load has greater capacity of retention and interaction stronger with molecules of water, but also has greater thermal stability. The samples present biomaterial potential with prospects of endodontic use, which showed cell viability in L929 fibroblast cell culture above 70.00%. [ABSTRACT FROM AUTHOR]

The aim of this work was to develop silico-aluminous vitreous monoliths pure and doped with neodymium and erbium ions using the sol-gel method. Molar proportions of tetraethylorthosilicate:etanol:deionized water:aluminum acetate:nitric acid were 1:2:2:0.03:0.05 mol, respectively. The molar ratio of lanthanide in vitreous monoliths was 0.01, 0.02 and 0.04 mol. The mixture was stirred on a heated plate at 60 °C for 2 h, after being poured into cylindrical acrylic molds. The monoliths were dried at 25 °C for 20 days. The samples were characterized by TG, DTA, XRD, FTIR, UV-Vis and luminescence spectroscopy. Based on the verified properties, the obtained monoliths have great potential for applications in photonic devices, such as solid-state lasers used in optical spectroscopy and medical-surgical and dental procedures. [ABSTRACT FROM AUTHOR]

We analyzed the numerical values of half-lifes of excited electronic states of the H, He and Li atom, as well as the [Li.sup.+] ion. By means of a fractal scaling model originally published by Muller in this journal, we interprete these half-lifes as proton resonance periods. On the logarithmic scale, the half-lifes were expressed by short continued fractions, where all numerators are Euler's number. From this representation it was concluded that the half-lifes are heavily located in nodes or sub-nodes of the spectrum of proton resonance periods., 1 Introduction The model of a chain of similar harmonic oscillators was proposed by Muller [1-3] as a phenomenological theory describing physical quantities as proton resonance oscillation modes. In the [...]

A numerical analysis revealed that masses, radii, distances from the sun, orbital periods and rotation periods of celestial bodies can be expressed on the logarithmic scale though a systematic set of numbers: 4e, 2e, e, |, | and 16. We analyzed these data with a fractal scaling model originally published by Muller in this journal, interpreting physical quantities as proton resonances. The data were expressed in continued fraction form, where all numerators are Euler's number. From these continued fractions, we explain the volcanic activity on Venus, the absence of infrared emission of Uranus and why Jupiter and Saturn emit more infrared radiation than they receive as total radiation energy from the Sun. We also claim that the Kuiper cliff was not caused by a still unknown planet. It can be understood why some planets have an atmosphere and others not, as well as why the ice on dwarf planet Ceres does not evaporate into space through solar radiation. The results also suggest that Jupiter and Saturn have the principal function to capture asteroids and comets, thus protecting the Earth, a fact which is well-reflected in the high number of their irregular satellites., 1 Introduction Recently in three papers of this journal, Muller [1-3] suggested a chain of similar harmonic oscillators as a general model to describe physical quantities as proton resonance oscillation [...]