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Hydrogel features can be designed and optimized using different crosslinking agents to meet specific requirements. In this regard, the present work investigates the physico-chemical features of cellulose-based hydrogels, designed by using different epoxy crosslinkers from the same glycidyl family, namely epichlorohydrin (ECH), 1,4-butanediol diglycidyl ether (BDDE), and trimethylolpropane triglycidyl ether (TMPTGE). The effect of the crosslinker's structure (from simple to branched) and functionality (mono-, bi- and tri-epoxy groups) on the hydrogels' features was studied. The performances of the hydrogels were investigated through the gel fraction, as well as by ATR-FTIR, DVS, SEM, DSC, and TG analyses. Also, the swelling and rheological behaviors of the hydrogels were examined. The advantages and limitations of each approach were discussed and a strong correlation between the crosslinker structure and the hydrogel properties was established. The formation of new ether bonds was evidenced by ATR-FTIR spectroscopy. It was emphasized that the pore size is directly influenced by the crosslinker type, namely, it decreases with the increasing number of epoxy groups from the crosslinker molecule, i.e., from 46 ± 11.1 µm (hydrogel CE, with ECH) to 12.3 ± 2.5 µm (hydrogel CB, with BDDE) and 6.7 ± 1.5 µm (hydrogel CT, with TMPTGE). The rheological behavior is consistent with the swelling data and hydrogel morphology, such as CE with the highest Qmax and the largest pore size being relatively more elastic than CB and CT. Instead, the denser matrices obtained by using crosslinkers with more complex structures have better thermal stability. The experimental results highlight the possibility of using a specific crosslinking agent, with a defined structure and functionality, in order to establish the main characteristics of hydrogels and, implicitly, to design them for a certain field of application.
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Eying the increasing impact of hyaluronic acid (HA) and its multifaceted applications, this study employs a non-toxic, one-pot strategy to develop injectable, self-healing hydrogels for biomedical applications. Phytic acid (PA), a plant-derived organic acid with high biocompatibility and numerous hydroxyl groups, can act as a cross-linking agent to form hydrogen-bonded networks with the HA chains. The study examined the optimal mass ratio of HA to PA to achieve superior hydrogel performance. Fourier transform infrared spectroscopy, rheological studies, and thermal analysis confirmed the successful formation of the hydrogels, which exhibited injectability, rapid self-healing, malleability, and elasticity. The investigation of different compositions revealed a sensitive influence of PA on the self-assembly phenomena of HA during flow. SEM cross-section images of the freeze-dried gels revealed a porous surface in the form of an interconnected network of microchannels. In addition, the hydrogel exhibits good tissue adhesion properties and promotes cell proliferation in biocompatibility tests on human gingival fibroblasts. The significance of this study lies in the ability of the proposed materials to be injected, to conform to the complex 3D structure of host tissues as well as their ability to recover after damage, indicating significant potential as scaffolds for wound healing.
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Composite membranes based on a polymer mixture solution of quaternized polysulfone (PSFQ), cellulose acetate phthalate (CAP), and polyvinylidene fluoride (PVDF) for biomedical applications were successfully obtained through the electrospinning technique. To ensure the polysulfone membranes' functionality in targeted applications, the selection of electrospinning conditions was essential. Moreover, understanding the geometric characteristics and morphology of fibrous membranes is crucial in designing them to meet the performance standards necessary for future biomedical applications. Thus, the viscosity of the solutions used in the electrospinning process was determined, and the morphology of the electrospun membranes was examined using scanning electron microscopy (SEM). Investigations on the surfaces of electrospun membranes based on water vapor sorption data have demonstrated that their surface properties dictate their biological ability more than their specific surfaces. Furthermore, in order to understand the different macromolecular rearrangements of membrane structures caused by physical interactions between the polymeric chains as well as by the orientation of functional groups during the electrospinning process, Fourier transform infrared (FTIR) spectroscopy was used. The applicability of composite membranes in the biomedical field was established by bacterial adhesion testing on the surface of electrospun membranes using Escherichia coli and Staphylococcus aureus microorganisms. The biological experiments conducted establish a foundation for future applications of these membranes and validate their effectiveness in specific fields.
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The new palladium(II) complex, [Pd(C16H16N4O3)2](CF3COO)2·2CF3COOH, crystallizes in the triclinic space group P with the asymmetric unit containing half the cation (PdII site symmetry Ci ), one tri-fluoro-actetate anion and one co-crystallized tri-fluoro-acetic acid mol-ecule. Two neutral chelating 2-[5-(3,4,5-tri-meth-oxy-phen-yl)-4H-1,2,4-triazol-3-yl]pyridine ligands coordinate to the PdII ion through the triazole-N and pyridine-N atoms in a distorted trans-PdN4 square-planar configuration [Pd-N 1.991â (2), 2.037â (2)â Å; cis N-Pd-N 79.65â (8), 100.35â (8)°]. The complex cation is quite planar, except for the methoxo groups (δ = 0.117â Å for one of the C atoms). The planar configuration is supported by two intra-molecular C-Hâ¯N hydrogen bonds. In the crystal, the π-π-stacked cations are arranged in sheets parallel to the ab plane that are flanked on both sides by the tri-fluoro-acetic acid-tri-fluoro-acetate anion pairs. Apart from classical N/O-Hâ¯O hydrogen-bonding inter-actions, weak C-Hâ¯F/N/O contacts consolidate the three-dimensional architecture. Both tri-fluoro-acetic moieties were found to be disordered over two resolvable positions with a refined occupancy ratio of 0.587â (1):0.413â (17) and 0.530â (6):0.470â (6) for the protonated and deprotonated forms, respectively.
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The multiple uses of cellulose nanofibrils (CNFs) originate from their availability from renewable resources, and are due to their physico-chemical properties, biodegradability and biocompatibility. At the same time, reducing sensitivity to humidity, increasing interfacial adhesion and hydrophobic modification of the CNF surface to diversify applications and improve operation, are current targets pursued. This study focuses on the preparation of a novel gel structure using cellulose nanofibrils (CNFs) and poly(ethylene brassylate-co-squaric acid) (PEBSA50/50), a bio-based copolymacrolactone. The primary goal is to achieve the gel with reduced sensitivity to humidity and enhanced hydrophobic behaviour. The new system was characterized in comparison to its constituent components using various techniques, such as Fourier transform infrared spectroscopy, thermal analysis, X-ray diffraction, and NIR - chemical imaging. Rheological tests demonstrated the formation of the CNF_PEBSA50/50 gel as a result of physical interactions between the two polymeric partners and revealed self-healing abilities for the prepared gels. Determination of the contact angle, surface free energy, as well as dynamic measurements of the vapour sorption of the CNF_PEBSA50/50 system, confirmed the achievement of the study's aim. Furthermore, the CNF_PEBSA50/50 network was utilized to encapsulate citric acid, resulting in the creation of a new bioactive composite with both antioxidant and antimicrobial activity.
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Celulosa , Nanofibras , Celulosa/química , Antioxidantes/farmacología , Polímeros , Interacciones Hidrofóbicas e Hidrofílicas , Nanofibras/químicaRESUMEN
The title compound, N 1,N 2-di-methyl-ethane-dihydrazide, C4H10N4O2, was obtained by the methyl-ation of oxalyl dihydrazide protected with phthalimide. The mol-ecule is essentially non-planar with a dihedral angle between the two planar hydrazide fragments of 86.5â (2)°. This geometry contributes to the formation of a multi-contact three-dimensional supra-molecular network via C-Hâ¯O, N-Hâ¯O and N-Hâ¯N hydrogen bonds.
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The asymmetric unit of the title compound, catena-poly[[[aqua-bis-(pyridine-κN)cadmium(II)]-µ2-4,4'-(1H-1,2,4-triazole-3,5-di-yl)dibenzoato-κ4 O,O':O'',O'''] 4.5-hydrate], {[Cd(C16H9N3O4)(C5H5N)2(H2O)]·4.5H2O}n or {[Cd(bct)(py)2(H2O)]·4.5H2O}n (I), consists of a Cd2+ cation coordinated to one bct2- carboxyl-ate dianion, two mol-ecules of pyridine and a water mol-ecule as well as four and a half water mol-ecules of crystallization. The metal ion in I possesses a penta-gonal-bipyramidal environment with the four O atoms of the two bidentately coordinated carboxyl-ate groups and the N atom of a pyridine mol-ecule forming the O4N equatorial plane, while the N atom of another pyridine ligand and the O atom of the water mol-ecule occupy the axial positions. The bct2- bridging ligand connects two metal ions via its carb-oxy-lic groups, resulting in the formation of a parallel linear polymeric chain running along the [11] direction. The coordinated water mol-ecule of one chain forms a strong O-Hâ¯O hydrogen bond with the carboxyl-ate O atom of a neighboring chain, leading to the formation of double chains with a closest distance of 5.425â (7)â Å between the cadmium ions belonging to different chains. Aromatic π-π stacking inter-actions between the benzene fragments of the anions as well as between the coordinated pyridine mol-ecules belonging to different chains results in the formation of sheets oriented parallel to the (01) plane. As a result of hydrogen-bonding inter-actions involving the water mol-ecules of crystallization, the sheets are joined together in a three-dimensional network.
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This study reports a simple and low-cost method for water purification using recyclable natural fibers (coarse wool fibers) as column-filling media for adsorption in the dynamic mode. As an instance of a dissolved organic pollutant, a cationic dye (basic blue 9, BB9) was assayed. According to the Langmuir isotherm (recorded at 300 K), the calculated maximum adsorption capacity of the fibrous material was found to be 24.86 mg/g for the retention of BB9. Response surface methodology (RSM) was employed for the design of experiments and the model-based optimization of the adsorption process performed in the dynamic regime (fixed-bed column). The optimal conditions provided by RSM indicated an adsorbent column height of H = 13.5 cm and a feed flow rate of Fv = 3 mL/min; these operating parameters ensured a color removal efficiency of 92.56% after 240 min of contact time. The recorded breakthrough curve under the optimal conditions was further interpolated using five quantitative mathematical models (Adams-Bohart, Thomas, Yoon-Nelson, Yan, and Clark) to assess the dynamic behaviors in the fixed-bed column. The best goodness-of-fit was achieved for the Thomas and Yoon-Nelson models. Thus, the coarse wool fibers used in a fixed bed demonstrated a relevant efficiency in the removal of cationic organic pollutants from contaminated water.
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In this paper, the synthesis and characterization of two polycaprolactone-polydimethylsiloxane (PDMS-CL) copolymers with biodegradable properties are reported. A comparative study was carried out using an aminopropyl-terminated polydimethylsiloxane macro-initiator (APDMS) with two different molecular weights. The copolymers (PDMS-CL-1 and PDMS-CL-2) were obtained by ring-opening polymerization of É-caprolactone using APDMS as initiators and stannous 2-ethylhexanoate as a catalyst. The copolymer's structures were confirmed by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H-NMR) spectra, and energy dispersion spectroscopy (EDX). Surface morphology was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The hydrophobic properties of the copolymers were demonstrated by the water contact angle and water vapor sorption capacity. Additionally, biological tests were conducted on San Marzano type tomato plants (Lypercosium esculentum) to assess the synthesized copolymers' susceptibility to the environment in terms of biological stability and metabolic activity. The biodegradation of PDMS-CL-1 and PDMS-CL-2 copolymers does not have a dangerous effect on the metabolic activity of plants, which makes it a convenient product in interaction with the environment.
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Background and Objectives: One's quality of life depends on overall health, and in particular, oral health, which has been and continues to become a public health issue through frequent manifestations in various forms, from simple oral stomatitis (inflammations of the oral cavity) to the complicated oral health pathologies requiring medical interventions and treatments (caries, pulp necrosis and periodontitis). The aim of this study focused on the preparation and evaluation of vitamins (vitamin A, B1 and B6) incorporated into several silicone-based lining materials as a new alternative to therapeutically loaded materials designed as oral cavity lining materials in prosthodontics. Materials and Methods: Silicone-based liners containing vitamins were prepared by mixing them in solution and becoming crosslinked, and then they were characterized using Fourier-transform infrared (FT-IR) spectroscopy to confirm the incorporation of the vitamins into the silicone network; scanning electron microscopy (SEM) to evidence the morphology of the liner materials; dynamic vapor sorption (DVS) to evaluate their internal hydrophobicity, swelling in environments similar to biological fluids and mechanical test to demonstrate tensile strength; MTT to confirm their biocompatibility on normal cell cultures (fibroblast) and mucoadhesivity; and histopathological tests on porcine oral mucosa to highlight their potential utility as soft lining materials with improved efficiency. Results: FT-IR analysis confirmed the structural peculiarities of the prepared lining materials and the successful incorporation of vitamins into the silicone matrix. The surface roughness of the materials was lower than 0.2 µm, while in cross-section, the lining materials showed a compact morphology. It was found that the presence of vitamins induced a decrease in the main mechanical parameters (strength and elongation at break, Young's modulus) and hydrophobicity, which varied from one vitamin to another. A swelling degree higher than 8% was found in PBS 6.8 (artificial saliva) and water. Hydrolytic stability studies in an artificial saliva medium showed the release of low concentrations of silicone and vitamin fragments in the first 24 h, which increased the swelling behavior of the materials, diffusion and solubility of the vitamins. The microscopic images of fibroblast cells incubated with vitamin liners revealed very good biocompatibility. Also, the silicone liners incorporating the vitamins showed good mucoadhesive properties. The appearance of some pathological disorders with autolysis processes was more pronounced in the case of vitamin A liners. Conclusions: The addition of the vitamins was shown to have a beneficial effect that was mainly manifested as increased biocompatibility, hydrolytic stability and mucoadhesiveness with the mucosa of the oral cavity and less of an effect on the mechanical strength. The obtained lining materials showed good resistance in simulated biological media but caused a pronounced autolysis phenomenon, as revealed by histopathological examination, showing that these materials may have broad implications in the treatment of oral diseases.
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Alineadores Dentales , Elastómeros de Silicona , Animales , Porcinos , Elastómeros de Silicona/química , Vitaminas , Vitamina A , Mucosa Bucal , Calidad de Vida , Saliva Artificial , Espectroscopía Infrarroja por Transformada de Fourier , Ensayo de Materiales , Vitamina KRESUMEN
Multicomponent composites based on natural biopolymers: chitosan, starch and gelatin in two different ratios (0.5:1:1 and 1:1:1) were in situ crosslinked by intermolecular interactions and used as matrices for zinc oxide and magnetite fillers. The bionanocomposite films have been evaluated by spectral and microscopy methods: Fourier-Transform Infrared spectrometry (FT-IR), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) confirming the electrostatic and hydrogen bonding interactions between the components of the polymeric matrices and the inorganic fillers and the crosslinking process. AFM and SEM images showed a compact, non-porous and homogenous morphology of the hybrid films, proving a good miscibility of the blends. At lower concentrations of embedded filler, the composites were less hardened and more ductile due to the interaction with the polymeric matrix. Increased amounts of inorganic NPs led to the reduced mechanical properties of the prepared materials and increased thermal stability. The bionanocomposites revealed a similar behavior of the dielectric constant with frequency and increased values at higher temperatures. The wettability of the films' surface and the values of the water sorption capacity revealed a slight hydrophilicity of the bionanocomposites as compared with the initial matrices. The biocompatibility, evaluated by means of the surface free energy components and the interfacial tension with blood, and the hemolysis analysis demonstrated that the bionanocomposites possess a low risk of thrombosis, being promising materials for in vivo biomedical applications.
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Quitosano , Nanopartículas del Metal , Nanocompuestos , Quitosano/química , Almidón/química , Gelatina/química , Espectroscopía Infrarroja por Transformada de Fourier , Nanocompuestos/químicaRESUMEN
Dental composites, through their structural diversity, represent the biomaterials frequently used in dental reconstructive therapy. The aim of our study was to observe the influence of different beverage environment conditions on seven types of obturation dental materials with different compositions. Our research focused on the surface modification analysis of the materials after the immersion in the different beverages; in this regard, we used the EDAX technique correlated with the energy-dispersive X-ray fluorescence (XRF). The pH of the drinks and that of the simulated saliva solution were determined by the titrimetric method, a sodium hydroxide solution 0.1 mol/dm3 was prepared and used for the titration. An amount of 5 mL of each analyzed solution was added to 15 mL of distilled water to obtain a dilution, to which 3 drops of phenolphthalein (as a color indicator-Phenolphthalein, 3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone, C20H14O4 Mw: 318.32, purchased from Merck) were added for each analysis. For each solution, the experiment was repeated three times in order to obtain accurate results. The results of our study materialized into a real plea for modifying the patients' behavior in terms of diet and preferences for acidic drinks, so that their quality-of-life valence can be improved by keeping the composite materials in a long-term unalterable state on the one hand; on the other hand, systemic damage can be prevented as well.
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New composite materials were prepared via cross-linking of polyethylene glycol/2-hydroxypropyl-ß-cyclodextrins polyrotaxane (PEG/HPßCD) and polyisoprene/HPßCD semi-polyrotaxane (PI/HPßCD SR) with 1,6-hexamethylene diizocyanate (HMDI). Advanced instrumental methods (such WAXS (wide angle X-ray scattering), AFM (atomic force microscopy), SEM (scanning electron microscopy), and thermal and dynamic vapor sorption) were employed for the structural, morphological and thermal characterization of the resulting composite materials. The roughness parameters calculated using AFM indicate a smoother surface for the composite material with 10 wt% of PI/HPßCD SR, denoting that a homogeneous film was obtained. SEM analysis reveals porous morphologies for both composite materials and the pore sizes increase with the increasing concentration of PI/HPßCD SR in the matrix. Dynamic vapor sorption/desorption measurements and type IV isotherms confirmed the hydrophilic and porous materials, which are in agreement with SEM analysis. The composite with a higher PI/HPßCD SR concentration in the matrix showed increased thermal stability than that of the pure cross-linked material. This material was further tested as a sorbent for methylene blue (MB) dye removal from an aqueous solution. The adsorption capacity of the composite film was found to be 2.58 mg g-1 at 25 °C.
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In recent years, multidrug-resistant bacteria have developed the ability to resist multiple antibiotics, limiting the available options for effective treatment. Raising awareness and providing education on the appropriate use of antibiotics, as well as improving infection control measures in healthcare facilities, are crucial steps to address the healthcare crisis. Further, innovative approaches must be adopted to develop novel drug delivery systems using polymeric matrices as carriers and support to efficiently combat such multidrug-resistant bacteria and thus promote wound healing. In this context, the current work describes the use of two biocompatible and non-toxic polymers, poly(vinyl alcohol) (PVA) and xanthan gum (XG), to achieve hydrogel networks through cross-linking by oxalic acid following the freezing/thawing procedure. PVA/XG-80/20 hydrogels were loaded with different quantities of neomycin sulfate to create promising low-class topical antibacterial formulations with enhanced antimicrobial effects. The inclusion of neomycin sulfate in the hydrogels is intended to impart them with powerful antimicrobial properties, thereby facilitating the development of exceptionally efficient topical antibacterial formulations. Thus, incorporating higher quantities of neomycin sulfate in the PVA/XG-80/20-2 and PVA/XG-80/20-3 formulations yielded promising cycling characteristics. These formulations exhibited outstanding removal efficiency, exceeding 80% even after five cycles, indicating remarkable and consistent adsorption performance with repeated use. Furthermore, both PVA/XG-80/20-2 and PVA/XG-80/20-3 formulations outperformed the drug-free sample, PVA/XG-80/20, demonstrating a significant enhancement in maximum compressive stress.
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Cellulose acetate is of remarkable scientific interest, becoming more useful when is used in obtaining of the composite materials containing nanoparticles, as result of its improved properties. Thus, cellulose acetate/silica composite films obtained by casting the solutions of cellulose acetate (CA)/tetraethyl orthosilicate (TEOS) in different mixing ratios were analyzed in this paper. The impact of TEOS addition, and implicitly of the silica nanoparticles on the mechanical strength, water vapor sorption properties and antimicrobial activity of the cellulose acetate/silica films were mainly monitored. The results of the tensile strength tests were discussed in correlation with data obtained from Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. It was found that samples with low TEOS content show improved mechanical strength compared to samples with high amounts of TEOS. The microstructural characteristics of the studied films affect their moisture sorption capacity so that the weight of the adsorbed water increases with the addition of TEOS. These features are complemented with the antimicrobial activity against Staphylococcus aureus and Escherichia coli bacterial species. The obtained data show that the cellulose acetate/silica films, and especially those with low silica content have improved properties that can recommend them for applications in the biomedical field.
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Antiinfecciosos , Dióxido de Silicio , Dióxido de Silicio/química , Resistencia a la Tracción , Celulosa/química , Antiinfecciosos/farmacología , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
The progress achieved in recent years in the biomedical field justifies the objective evaluation of new techniques and materials obtained by using silver in different forms as metallic silver, silver salts, and nanoparticles. Thus, the antibacterial, antiviral, antifungal, antioxidant, and anti-inflammatory activity of silver nanoparticles (AgNPs) confers to newly obtained materials characteristics that make them ideal candidates in a wide spectrum of applications. In the present study, the use of hydroxypropyl methyl cellulose (HPMC) in the new formulation, by embedding AgNPs with antibacterial activity, using poly(N-vinylpyrrolidone) (PVP) as a stabilizing agent was investigated. AgNPs were incorporated in HPMC solutions, by thermal reduction of silver ions to silver nanoparticles, using PVP as a stabilizer; a technique that ensures the efficiency and selectivity of the obtained materials. The rheological properties, morphology, in vitro antimicrobial activity, and stability/catching of Ag nanoparticles in resulting HPMC/PVP-AgNPs materials were evaluated. The obtained rheological parameters highlight the multifunctional roles of PVP, focusing on the stabilizing effect of new formulations but also the optimization of some properties of the studied materials. The silver amount was quantified using the spectroscopy techniques (energy-dispersive X-ray fluorescence (XRF), energy-dispersive X-ray spectroscopy (EDX)), while formation of the AgNPs was confirmed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic light scattering (DLS). Also, the morphological examination (Atomic Force Microscopy (AFM) and Scanning electron microscopy (SEM)) by means of the texture roughness parameters has evidenced favorable characteristics for targeted applications. Antibacterial activity was tested against Escherichia coli and Staphylococcus aureus and was found to be substantially improved was silver was added in the studied systems.
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Herein, we report the results of a study on combining adsorption and ultrafiltration in a single-stage process to remove nitrite ions from contaminated water. As adsorbent, a surface-modified nanoclay was employed (i.e., Nanomer® I.28E, containing 25-30 wt. % trimethyl stearyl ammonium). Ultrafiltration experiments were conducted using porous polymeric membranes (Ultracel® 10 kDa). The hybrid process of adsorption-ultrafiltration was modeled and optimized using three computational tools: (1) response surface methodology (RSM), (2) artificial neural network (ANN), and (3) support vector machine (SVM). The optimal conditions provided by machine learning (SVM) were found to be the best, revealing a rejection efficiency of 86.3% and an initial flux of permeate of 185 LMH for a moderate dose of the nanoclay (0.674% w/v). Likewise, a new and more retentive membrane (based on PVDF-HFP copolymer and halloysite (HS) inorganic nanotubes) was produced by the phase-inversion method, characterized by SEM, EDX, AFM, and FTIR techniques, and then tested under optimal conditions. This new composite membrane (PVDF-HFP/HS) with a thickness of 112 µm and a porosity of 75.32% unveiled an enhanced rejection efficiency (95.0%) and a lower initial flux of permeate (28 LMH). Moreover, molecular docking simulations disclosed the intermolecular interactions between nitrite ions and the functional moiety of the organonanoclay.
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The study presents the achievement of a new assembly with antioxidant behaviour based on a copolymacrolactone structure that encapsulates erythritol (Eryt). Poly(ethylene brassylate-co-squaric acid) (PEBSA) was synthesised in environmentally friendly conditions, respectively, through a process in suspension in water by opening the cycle of ethylene brassylate macrolactone, followed by condensation with squaric acid. The compound synthesised in suspension was characterised by comparison with the polymer obtained by polymerisation in solution. The investigations revealed that, with the exception of the molecular masses, the compounds generated by the two synthetic procedures present similar properties, including good thermal stability, with a Tpeak of 456 °C, and the capacity for network formation. In addition, the investigation by dynamic light scattering techniques evidenced a mean diameter for PEBSA particles of around 596 nm and a zeta potential of -25 mV, which attests to their stability. The bio-based copolymacrolactone was used as a matrix for erythritol encapsulation. The new PEBSA-Eryt compound presented an increased sorption/desorption process, compared with the PEBSA matrix, and a crystalline morphology confirmed by X-ray diffraction analysis. The bioactive compound was also characterised in terms of its biocompatibility and antioxidant behaviour.
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Silicone elastomer composites with piezoelectric properties, conferred by incorporated polyimide copolymers, with pressure sensors similar to human skin and kinetic energy harvester capabilities, were developed as thin film (<100 micron thick) layered architecture. They are based on polymer materials which can be produced in industrial amounts and are scalable for large areas (m2). The piezoelectric properties of the tested materials were determined using a dynamic mode of piezoelectric force microscopy. These composite materials bring together polydimethylsiloxane polymers with customized poly(siloxane-imide) copolymers (2−20 wt% relative to siloxanes), with siloxane segments inserted into the structure to ensure the compatibility of the components. The morphology of the materials as free-standing films was studied by SEM and AFM, revealing separated phases for higher polyimide concentration (10, 20 wt%). The composites show dielectric behavior with a low loss (<10−1) and a relative permittivity superior (3−4) to pure siloxane within a 0.1−106 Hz range. The composite in the form of a thin film can generate up to 750 mV under contact with a 30 g steel ball dropped from 10 cm high. This capability to convert a pressure signal into a direct current for the tested device has potential for applications in self-powered sensors and kinetic energy-harvesting applications. Furthermore, the materials preserve the known electromechanical properties of pure polysiloxane, with lateral strain actuation values of up to 6.2% at 28.9 V/µm.
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Electricidad , Polímeros , Humanos , Polímeros/química , SiloxanosRESUMEN
Two chemical motifs of interest for medicinal chemistry, silatrane as 1-(3-aminopropyl) silatrane (SIL M), and nitro group attached in position 5 to salicylaldehyde, are coupled in a new structure, 1-(3-{[(2-hydroxy-5-nitrophenyl)methylidene]amino}propyl)silatrane (SIL-BS), through an azomethine moiety, also known as a versatile pharmacophore. The high purity isolated compound was structurally characterized by an elemental, spectral, and single crystal X-ray diffraction analysis. Given the structural premises for being a biologically active compound, different specific techniques and protocols have been used to evaluate their in vitro hydrolytic stability in simulated physiological conditions, the cytotoxicity on two cancer cell lines (HepG2 and MCF7), and protein binding ability-with a major role in drug ADME (Absorption, Distribution, Metabolism and Excretion), in parallel with those of the SIL M. While the latter had a good biocompatibility, the nitro-silatrane derivative, SIL-BS, exhibited a higher cytotoxic activity on HepG2 and MCF7 cell lines, performance assigned, among others, to the known capacity of the nitro group to promote a specific cytotoxicity by a "activation by reduction" mechanism. Both compounds exhibited increased bio- and muco-adhesiveness, which can favor an optimized therapeutic effect by increased drug permeation and residence time in tumor location. Additional benefits of these compounds have been demonstrated by their antimicrobial activity on several fungi and bacteria species. Molecular docking computations on Human Serum Albumin (HSA) and MPRO COVID-19 protease demonstrated their potential in the development of new drugs for combined therapy.