RESUMEN
Chitosan chemical functionalization is a powerful tool to provide novel materials for additive manufacturing strategies. The main aim of this study was the employment of computer-aided wet spinning (CAWS) for the first time to design and fabricate carboxymethyl chitosan (CMCS) scaffolds. For this purpose, the synthesis of a chitosan derivative with a high degree of O-substitution (1.07) and water soluble in a large pH range allowed the fabrication of scaffolds with a 3D interconnected porous structure. In particular, the developed scaffolds were composed of CMCS fibers with a small diameter (< 60 µm) and a hollow structure due to a fast non solvent-induced coagulation. Zn2+ ionotropic crosslinking endowed the CMCS scaffolds with stability in aqueous solutions, pH-sensitive water uptake capability, and antimicrobial activity against Escherichia coli and Staphylococcus aureus. In addition, post-printing functionalization through collagen grafting resulted in a decreased stiffness (1.6 ± 0.3 kPa) and a higher elongation at break (101 ± 9 %) of CMCS scaffolds, as well as in their improved ability to support in vitro fibroblast viability and wound healing process. The obtained results encourage therefore further investigation of the developed scaffolds as antimicrobial wound dressing hydrogels for skin regeneration.
Asunto(s)
Antibacterianos , Vendajes , Quitosano , Escherichia coli , Staphylococcus aureus , Andamios del Tejido , Cicatrización de Heridas , Quitosano/química , Quitosano/análogos & derivados , Quitosano/farmacología , Staphylococcus aureus/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Cicatrización de Heridas/efectos de los fármacos , Andamios del Tejido/química , Antibacterianos/farmacología , Antibacterianos/química , Animales , Ratones , Fibroblastos/efectos de los fármacos , Porosidad , Supervivencia Celular/efectos de los fármacos , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Materiales Biocompatibles/síntesis química , Reactivos de Enlaces Cruzados/química , HumanosRESUMEN
In this work, chitosan/collagen-based membranes loaded with 2,3-dihydrobenzofuran (2,3-DHB) were developed through a simple solvent-casting procedure for use in the treatment of cutaneous Leishmaniasis. The obtained membranes were characterized by elemental analysis, FTIR, TG, DSC, and XRD. Porosity, swelling, mechanical properties, hydrophilicity, and antioxidant activity were analyzed. In addition, assessment to the biocompatibility, through fibroblasts/keratinocytes and in vitro wound healing essays were performed. The obtained results show that the new 2,3-DHB loaded chitosan/collagen membrane presented high porosity and swelling capacity as well as maximum strength, hydrophilicity, and antioxidant activity higher in relation to the control. The tests of antileishmanial activity and the AFM images demonstrate great efficacy of inhibition growth of the parasite, superior to those from the standard therapeutic agent that is currently used: Amphotericin B. The new membranes are biocompatible and stimulated the proliferation of keratinocytes. SEM images clearly demonstrate that fibroblasts were able to adhere, maintained their characteristic morphology. The healing test evidenced that the membranes have adequate environment for promoting cell proliferation and growth. As the conventional treatments often use drugs with high toxicity, the as-developed new membranes proved to be excellent candidate to treat cutaneous Leishmaniasis and can be clearly indicated for further advanced studies in vivo.
Asunto(s)
Benzofuranos , Quitosano , Colágeno , Leishmaniasis Cutánea , Quitosano/química , Quitosano/farmacología , Leishmaniasis Cutánea/tratamiento farmacológico , Leishmaniasis Cutánea/parasitología , Benzofuranos/farmacología , Benzofuranos/química , Colágeno/química , Humanos , Membranas Artificiales , Antiprotozoarios/farmacología , Antiprotozoarios/química , Fibroblastos/efectos de los fármacos , Porosidad , Animales , Cicatrización de Heridas/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Antioxidantes/farmacología , Antioxidantes/química , Queratinocitos/efectos de los fármacosRESUMEN
A hybrid organic monolithic column made of poly(lauryl methacrylate-co-1,6-hexanediol dimethacrylate) and the metal-organic framework MIL-68(Al) was prepared for the first time. The column was used in capillary liquid chromatography, both in isocratic and gradient elution modes. Separation performance towards small molecules of different chemical nature (polycyclic aromatic hydrocarbons, alkylbenzenes, phenols, etc.) was studied. Monte Carlo simulations were made to both select the proper precursors to obtain empty metal-organic framework micropores in the monolithic polymer and also, to analyze the potential free access of the studied analytes into the micropores (necessary to improve mass transfer and column efficiency). The hereby synthesized metal-organic framework microcrystals allowed obtaining homogeneous hybrid monolithic columns. Adding of MIL-68(Al) (1030 m2 g-1 BET specific surface area) increased the surface area from 3.9 m2 g-1 for the parent monolith to 18.2 m2 g-1 for the hybrid column containing 8 mg mL-1 of the microcrystals. Chromatographic performance of this new column was evaluated by studying retention factors, resolution, and plate counts at room temperature. Different compounds, not completely resolved in the parent monolith, were partially or completely separated after metal-organic framework addition. Using the monolithic column with only 2 mg mL-1 of MIL-68(Al), five alkylbenzenes were completely separated with very symmetrical peak shapes, resolution factors up to 3.60 and plate counts of 4300 plates m-1 for n-hexylbenzene. This value is higher than those obtained by other authors who used organic monolithic columns with embedded metal-organic frameworks to perform separations at room temperature. Additionally, nine polycyclic aromatic hydrocarbons were partially or completely resolved in gradient elution mode. The hybrid monolithic columns exhibited very good intra-day (%RSD=1.9), inter-day (%RSD=2.6), and column-to-column (%RSD=4.3) reproducibility values. Easy and fast column preparation, and versatility to efficiently separate several compounds of different chemical nature in isocratic and gradient mode, makes this new hybrid column a very good option for the analysis of small molecules in capillary (or nano) HPLC.
Asunto(s)
Estructuras Metalorgánicas , Hidrocarburos Policíclicos Aromáticos , Cromatografía Líquida de Alta Presión/métodos , Estructuras Metalorgánicas/química , Hidrocarburos Policíclicos Aromáticos/aislamiento & purificación , Hidrocarburos Policíclicos Aromáticos/análisis , Hidrocarburos Policíclicos Aromáticos/química , Método de Montecarlo , Fenoles/aislamiento & purificación , Fenoles/análisis , Fenoles/química , PorosidadRESUMEN
BACKGROUND: Tissue engineering seeks to improve, maintain, or replace the biological functions of damaged organs or tissues with biological substitutes such as the development of scaffolds. In the case of bone tissue, they must have excellent mechanical properties like native bone. OBJECTIVE: In this work, three geometric models were designed for scaffolds with different structure lattices and porosity that could be biomechanically suitable and support cell growth for trabecular bone replacement applications in tissue engineering and regenerative medicine to the proximal femur area. METHODS: Geometries were designed using computer-aided design (CAD) software and evaluated using finite element analysis in compression tests. Three loads were considered according to the daily activity: 1177 N for slow walking, 2060 N for fast walking, and 245.25 N for a person in a bipedal position. All these loads for an adult weight of 75 kg. For each of them, three biomaterials were assigned: two polymers (poly-glycolic acid (PGA) and poly-lactic acid (PLA)) and one mineral (hydroxyapatite (HA)). 54 tests were performed: 27 for each of the tests. RESULTS: The results showed Young's modulus (E) between 1 and 4 GPa. CONCLUSION: If the resultant E is in the range of 0.1 to 5 GPa, the biomaterial is considered an appropriate alternative for the trabecular bone which is the main component of the proximal bone. However, for the models applied in this study, the best option is the poly-lactic acid which will allow absorbing the acting loads.
Asunto(s)
Diseño Asistido por Computadora , Análisis de Elementos Finitos , Ingeniería de Tejidos , Andamios del Tejido , Andamios del Tejido/química , Humanos , Ingeniería de Tejidos/métodos , Durapatita/química , Módulo de Elasticidad , Bioimpresión/métodos , Poliésteres/química , Porosidad , Simulación por Computador , Materiales Biocompatibles/química , Sustitutos de Huesos/química , Ácido Poliglicólico/química , Impresión Tridimensional , Ensayo de Materiales , HuesosRESUMEN
Advanced breast cancer remains a significant oncological challenge, requiring new approaches to improve clinical outcomes. This study investigated an innovative theranostic agent using the MCM-41-NH2-DTPA-Gd3âº-MIH nanomaterial, which combined MRI imaging for detection and a novel chemotherapy agent (MIH 2.4Bl) for treatment. The nanomaterial was based on the mesoporous silica type, MCM-41, and was optimized for drug delivery via functionalization with amine groups and conjugation with DTPA and complexation with Gd3+. MRI sensitivity was enhanced by using gadolinium-based contrast agents, which are crucial in identifying early neoplastic lesions. MIH 2.4Bl, with its unique mesoionic structure, allows effective interactions with biomolecules that facilitate its intracellular antitumoral activity. Physicochemical characterization confirmed the nanomaterial synthesis and effective drug incorporation, with 15% of MIH 2.4Bl being adsorbed. Drug release assays indicated that approximately 50% was released within 8 h. MRI phantom studies demonstrated the superior imaging capability of the nanomaterial, with a relaxivity significantly higher than that of the commercial agent Magnevist. In vitro cellular cytotoxicity assays, the effectiveness of the nanomaterial in killing MDA-MB-231 breast cancer cells was demonstrated at an EC50 concentration of 12.6 mg/mL compared to an EC50 concentration of 68.9 mg/mL in normal human mammary epithelial cells (HMECs). In vivo, MRI evaluation in a 4T1 syngeneic mouse model confirmed its efficacy as a contrast agent. This study highlighted the theranostic capabilities of MCM-41-NH2-DTPA-Gd3âº-MIH and its potential to enhance breast cancer management.
Asunto(s)
Neoplasias de la Mama , Imagen por Resonancia Magnética , Nanopartículas , Dióxido de Silicio , Nanomedicina Teranóstica , Dióxido de Silicio/química , Animales , Humanos , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/patología , Femenino , Nanomedicina Teranóstica/métodos , Imagen por Resonancia Magnética/métodos , Ratones , Línea Celular Tumoral , Nanopartículas/química , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/uso terapéutico , Medios de Contraste/química , Gadolinio/química , Porosidad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Liquid chromatography-mass spectrometry (LC-MS) has emerged as a powerful analytical technique for analyzing complex biological samples. Among various chromatographic stationary phases, porous graphitic carbon (PGC) columns have attracted significant attention due to their unique properties-such as the ability to separate both polar and non-polar compounds and their stability through all pH ranges and to high temperatures-besides the compatibility with LC-MS. This review discusses the applicability of PGC for SPE and separation in LC-MS-based analyses of human biological samples, highlighting the diverse applications of PGC-LC-MS in analyzing endogenous metabolites, pharmaceuticals, and biomarkers, such as glycans, proteins, oligosaccharides, sugar phosphates, and nucleotides. Additionally, the fundamental principles underlying PGC column chemistry and its advantages, challenges, and advances in method development are explored. This comprehensive review aims to provide researchers and practitioners with a valuable resource for understanding the capabilities and limitations of PGC columns in LC-MS-based analysis of human biological samples, thereby facilitating advancements in analytical methodologies and biomedical research.
Asunto(s)
Grafito , Espectrometría de Masas , Humanos , Grafito/química , Cromatografía Liquida/métodos , Porosidad , Espectrometría de Masas/métodos , Extracción en Fase Sólida/métodos , Biomarcadores/análisis , Proteínas/análisis , Polisacáridos/análisis , Cromatografía Líquida con Espectrometría de MasasRESUMEN
The objective of this study was to create injectable photo-crosslinkable biomaterials, using gelatin methacryloyl (GelMA) hydrogel, combined with a decellularized bone matrix (BMdc) and a deproteinized (BMdp) bovine bone matrix. These were intended to serve as bioactive scaffolds for dentin regeneration. The parameters for GelMA hydrogel fabrication were initially selected, followed by the incorporation of BMdc and BMdp at a 1% (w/v) ratio. Nano-hydroxyapatite (nHA) was also included as a control. A physicochemical characterization was conducted, with FTIR analysis indicating that the mineral phase was complexed with GelMA, and BMdc was chemically bonded to the amide groups of gelatin. The porous structure was preserved post-BMdc incorporation, with bone particles incorporated alongside the pores. Conversely, the mineral phase was situated inside the pore opening, affecting the degree of porosity. The mineral phase did not modify the degradability of GelMA, even under conditions of type I collagenase-mediated enzymatic challenge, allowing hydrogel injection and increased mechanical strength. Subsequently, human dental pulp cells (HDPCs) were seeded onto the hydrogels. The cells remained viable and proliferative, irrespective of the GelMA composition. All mineral phases resulted in a significant increase in alkaline phosphatase activity and mineralized matrix deposition. However, GelMA-BMdc exhibited higher cell expression values, significantly surpassing those of all other formulations. In conclusion, our results showed that GelMA-BMdc produced a porous and stable hydrogel, capable of enhancing odontoblastic differentiation and mineral deposition when in contact with HDPCs, thereby showing potential for dentin regeneration.
Asunto(s)
Pulpa Dental , Dentina , Gelatina , Ingeniería de Tejidos , Dentina/química , Ingeniería de Tejidos/métodos , Animales , Bovinos , Gelatina/química , Humanos , Pulpa Dental/citología , Metacrilatos/química , Reactivos de Enlaces Cruzados/química , Hidrogeles/química , Andamios del Tejido/química , Huesos , Células Cultivadas , PorosidadRESUMEN
Bioactive and biodegradable scaffolds that mimic the natural extracellular matrix of bone serve as temporary structures to guide new bone tissue growth. In this study, 3D-printed scaffolds composed of poly (lactic acid) (PLA)-tricalcium phosphate (TCP) (90-10 wt.%) were modified with 1%, 5%, and 10 wt.% of ZnO to enhance bone tissue regeneration. A commercial chain extender named Joncryl was incorporated alongside ZnO to ensure the printability of the composites. Filaments were manufactured using a twin-screw extruder and subsequently used to print 3D scaffolds via fused filament fabrication (FFF). The scaffolds exhibited a homogeneous distribution of ZnO and TCP particles, a reproducible structure with 300 µm pores, and mechanical properties suitable for bone tissue engineering, with an elastic modulus around 100 MPa. The addition of ZnO resulted in enhanced surface roughness on the scaffolds, particularly for ZnO microparticles, achieving values up to 241 nm. This rougher topography was responsible for enhancing protein adsorption on the scaffolds, with an increase of up to 85% compared to the PLA-TCP matrix. Biological analyses demonstrated that the presence of ZnO promotes mesenchymal stem cell (MSC) proliferation and differentiation into osteoblasts. Alkaline phosphatase (ALP) activity, an important indicator of early osteogenic differentiation, increased up to 29%. The PLA-TCP composite containing 5% ZnO microparticles exhibited an optimized degradation rate and enhanced bioactivity, indicating its promising potential for bone repair applications.
Asunto(s)
Materiales Biocompatibles , Regeneración Ósea , Fosfatos de Calcio , Diferenciación Celular , Proliferación Celular , Células Madre Mesenquimatosas , Osteoblastos , Poliésteres , Impresión Tridimensional , Ingeniería de Tejidos , Andamios del Tejido , Óxido de Zinc , Andamios del Tejido/química , Fosfatos de Calcio/química , Poliésteres/química , Regeneración Ósea/efectos de los fármacos , Ingeniería de Tejidos/métodos , Células Madre Mesenquimatosas/citología , Óxido de Zinc/química , Materiales Biocompatibles/química , Diferenciación Celular/efectos de los fármacos , Osteoblastos/citología , Osteogénesis/efectos de los fármacos , Ensayo de Materiales , Huesos , Regeneración Tisular Dirigida/métodos , Humanos , Animales , Fosfatasa Alcalina/metabolismo , Módulo de Elasticidad , Porosidad , Propiedades de SuperficieRESUMEN
To assess the effect of cleaning protocols on dentin contaminated with blood in reparative endodontic materials, bovine root samples were divided: no contamination (N); contamination (P); contamination and cleaning with saline (S), 2.5% NaOCl+saline (Na) or 2.5% NaOCl+17% EDTA+saline (NaE) and filled with: mineral trioxide aggregate (MTA), calcium-aluminate-cement (C), or C+collagen (Ccol) (n=13). The samples were evaluated for porosity, chemical composition, and bond strength. MTA porosity was lower than C (p=0.02) and higher than Ccol (p<0.001). P and NaE were similar (p=1.00), but higher than the other groups (p<0.001). MTA bond strength was similar to Ccol (p=0.777) and lower than C (p=0.028). P presented lower bond strength than the N (p<0.001); S and Na were similar to each other (p=0.969), but higher than P and lower than N (p<0.001). It was observed a predominance of mixed and cohesive failures. None of the samples showed Ca/P ratio values similar to human hydroxyapatite. This study showed that contamination with blood increased the materials porosity, but dentin cleaning with 2.5% NaOCl reduced this effect, and the collagen additive reduced the material porosity. Furthermore, blood contamination reduced the materials bond strength, and cleaning with saline or 2.5% NaOCl diminished this effect.
Asunto(s)
Sangre , Colágeno , Dentina , Porosidad , Bovinos , Dentina/efectos de los fármacos , Colágeno/química , Animales , Raíz del Diente/química , Silicatos/química , Compuestos de Calcio/química , Recubrimiento Dental Adhesivo/métodos , Compuestos de Aluminio/química , Cerámica/química , Ensayo de Materiales , Materiales Biocompatibles/química , Óxidos/química , Materiales de Obturación del Conducto Radicular/química , Combinación de Medicamentos , Hipoclorito de Sodio/químicaRESUMEN
Titanium-based implants have long been studied and used for applications in bone tissue engineering, thanks to their outstanding mechanical properties and appropriate biocompatibility. However, many implants struggle with osseointegration and attachment and can be vulnerable to the development of infections. In this work, we have developed a composite coating via electrophoretic deposition, which is both bioactive and antibacterial. Mesoporous bioactive glass particles with gentamicin were electrophoretically deposited onto a titanium substrate. In order to validate the hypothesis that the quantity of particles in the coatings is sufficiently high and uniform in each deposition process, an easy-to-use image processing algorithm was designed to minimize human dependence and ensure reproducible results. The addition of loaded mesoporous particles did not affect the good adhesion of the coating to the substrate although roughness was clearly enhanced. After 7 days of immersion, the composite coatings were almost dissolved and released, but phosphate-related compounds started to nucleate at the surface. With a simple and low-cost technique like electrophoretic deposition, and optimized stir and suspension times, we were able to synthesize a hemocompatible coating that significantly improves the antibacterial activity when compared to the bare substrate for both Gram-positive and Gram-negative bacteria.
Asunto(s)
Antibacterianos , Quitosano , Electroforesis , Gentamicinas , Vidrio , Ensayo de Materiales , Nanopartículas , Tamaño de la Partícula , Propiedades de Superficie , Titanio , Gentamicinas/farmacología , Gentamicinas/química , Titanio/química , Titanio/farmacología , Antibacterianos/farmacología , Antibacterianos/química , Vidrio/química , Nanopartículas/química , Quitosano/química , Quitosano/farmacología , Porosidad , Pruebas de Sensibilidad Microbiana , Humanos , Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/farmacología , Prótesis e Implantes , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacologíaRESUMEN
This study focuses on designing and evaluating scaffolds with essential properties for bone regeneration, such as biocompatibility, macroporous geometry, mechanical strength, and magnetic responsiveness. The scaffolds are made using 3D printing with acrylic resin and iron oxides synthesized through solution combustion. Utilizing triply periodic minimal surfaces (TPMS) geometry and mask stereolithography (MSLA) printing, the scaffolds achieve precise geometrical features. The mechanical properties are enhanced through resin curing, and magnetite particles from synthesized nanoparticles and alluvial magnetite are added for magnetic properties. The scaffolds show a balance between stiffness, porosity, and magnetic responsiveness, with maximum compression strength between 4.8 and 9.2 MPa and Young's modulus between 58 and 174 MPa. Magnetic properties such as magnetic coercivity, remanence, and saturation are measured, with the best results from scaffolds containing synthetic iron oxides at 1% weight. The viscosity of the mixtures used for printing is between 350 and 380 mPas, and contact angles between 90° and 110° are achieved. Biocompatibility tests indicate the potential for clinical trials, though further research is needed to understand the impact of magnetic properties on cellular interactions and optimize scaffold design for specific applications. This integrated approach offers a promising avenue for the development of advanced materials capable of promoting enhanced bone regeneration.
Asunto(s)
Regeneración Ósea , Impresión Tridimensional , Andamios del Tejido , Andamios del Tejido/química , Porosidad , Ingeniería de Tejidos/métodos , Humanos , Materiales Biocompatibles/química , Compuestos Férricos/química , Fenómenos Magnéticos , Animales , MagnetismoRESUMEN
Hibiscus extract exhibits considerable antioxidant activity and a high anthocyanin content, which suggesting potential health benefits. However, these compounds are highly susceptible to environmental factors. The aim of this study was to establish the optimal conditions for the encapsulation of Hibiscus sabdariffa extract (HSE) using mixed porous maize starch-gum Arabic to enhance the stability of bioactive compounds under accelerated aging conditions. Response surface methodology (RSM) was used to optimize microencapsulation conditions through spray drying. The optimal conditions for microencapsulation of HSE by RSM were determined to be 126 °C at the inlet temperature (IT) and 8.5 % at the total solid content (TSC). Using these conditions, the amount of bioactive compounds in optimized microcapsules (OMs) was 2368 mg GAE/100 g, 694 mg QE/100 g, and 930 mg EC3G/100 g, of phenolic compounds, flavonoids, and anthocyanin, respectively. The release rate of anthocyanins during in vitro digestion was more effectively regulated in the OM sample, which retained up to 40 % of anthocyanins compared with 10 % in the HSE. The experimental values in this study exhibit high assertiveness, which renders the optimization model technologically and financially viable for the encapsulation of bioactive compounds with potential use in the food and pharmaceutical industries.
Asunto(s)
Antocianinas , Composición de Medicamentos , Goma Arábiga , Hibiscus , Extractos Vegetales , Almidón , Hibiscus/química , Almidón/química , Goma Arábiga/química , Extractos Vegetales/química , Porosidad , Antocianinas/química , Cápsulas , Antioxidantes/química , Antioxidantes/farmacología , Tracto Gastrointestinal/metabolismo , Estabilidad de MedicamentosRESUMEN
This study evaluated the biocompatibility, bioactivity, porosity, and sealer/dentin interface of Sealer Plus BC (SP), Bio-C Sealer (BIOC), TotalFill BC Sealer (TF), and AH Plus (AHP). Dentin tubes filled with the sealers and empty tubes (control group) were implanted in the subcutaneous tissue of rats for different periods (n = 6 per group/period). Number of inflammatory cells (ICs), capsule thickness, von Kossa reaction, interleukin-6 (IL-6) and osteocalcin (OCN) were evaluated. Porosity and voids in the interface dentin/sealers were assessed by micro-computed tomography. The data were submitted to ANOVA/Tukey's tests (α = 0.05). Greater capsule thickness, ICs and IL-6 immunolabeling cells were observed in AHP. No significant difference in thickness of capsule, ICs, and IL-6- immunolabeling cells was detected between SP and TF, in all periods, and after 30 and 60 days between all groups. At 60 days all groups had reduction in capsule thickness, ICs and IL-6 immunolabeling cells. Von Kossa-positive and birefringent structures were observed in the capsules around the sealers. BIOC, SP, and TF exhibited OCN-immunolabeling cells. All sealers had porosity values below 5%, besides low and similar interface voids. BIOC, SP and TF are biocompatible, bioactive, and have low porosity and voids. The dentin-tube model used is an alternative for evaluating bioceramic materials.
Asunto(s)
Materiales Biocompatibles , Dentina , Ensayo de Materiales , Animales , Porosidad , Dentina/química , Dentina/metabolismo , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Ratas , Cerámica/química , Interleucina-6/metabolismo , Microtomografía por Rayos X , Masculino , Ratas Wistar , Selladores de Fosas y Fisuras/químicaRESUMEN
Persistent bacterial infections are the leading risk factor that complicates the healing of chronic wounds. In this work, we formulate mixtures of polyvinyl alcohol (P), chitosan (CH), collagen (C), and honey (H) to produce nanofibrous membranes with healing properties. The honey effect at concentrations of 0 % (PCH and PCHC), 5 % (PCHC-5H), 10 % (PCHC-10H), and 15 % (PCHC-15H) on the physicochemical, antibacterial, and biological properties of the developed nanofibers was investigated. Morphological analysis by SEM demonstrated that PCH and PCHC nanofibers had a uniform and homogeneous distribution on their surfaces. However, the increase in honey content increased the fiber diameter (118.11-420.10) and drastically reduced the porosity of the membranes (15.79-92.62 nm). The addition of honey reduces the water vapor transmission rate (WVTR) and the adsorption properties of the membranes. Mechanical tests revealed that nanofibers were more flexible and elastic when honey was added, specifically the PCHC-15H nanofibers with the lowest modulus of elasticity (15 MPa) and the highest elongation at break (220 %). Also, honey significantly improved the antibacterial efficiency of the nanofibers, mainly PCHC-15H nanofibers, which presented the best bacterial reduction rates against Staphylococcus aureus (59.84 %), Pseudomonas aeruginosa (47.27 %), Escherichia coli (65.07 %), and Listeria monocytogenes (49.58 %). In vitro tests with cell cultures suggest that nanofibers were not cytotoxic and exhibited excellent biocompatibility with human fibroblasts (HFb) and keratinocytes (HaCaT), since all treatments showed higher or similar cell viability as opposed to the cell control. Based on the findings, PVA-chitosan-collagen-honey nanofibrous membranes have promise as an antibacterial dressing substitute.
Asunto(s)
Antibacterianos , Vendajes , Quitosano , Colágeno , Miel , Membranas Artificiales , Nanofibras , Cicatrización de Heridas , Quitosano/química , Quitosano/farmacología , Nanofibras/química , Vendajes/microbiología , Colágeno/química , Antibacterianos/farmacología , Antibacterianos/química , Humanos , Cicatrización de Heridas/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Porosidad , Alcohol Polivinílico/química , Fibroblastos/efectos de los fármacosRESUMEN
Scaffolds for the filling and regeneration of osteochondral defects are a current challenge in the biomaterials field, and solutions with greater functionality are still being sought. The novel approach of this work was to obtain scaffolds with biologically active additives possessing microstructural, permeability, and mechanical properties, mimicking the complexity of natural cartilage. Four types of scaffolds with a gelatin/alginate matrix modified with hydroxyapatite were obtained, and the relationship between the modifiers and substrate properties was evaluated. They differed in the type of second modifier used, which was hydrated MgCl2 in two proportions, ZnO, and nanohydroxyapatite. The samples were obtained by freeze-drying by using two-stage freezing. Based on microstructural observations combined with X-ray microanalysis, the microstructure of the samples and the elemental content were assessed. Permeability and mechanical tests were also performed. The scaffolds exhibited a network of interconnected pores and complex microarchitecture, with lower porosity at the surface (15 ± 7 to 29 ± 6%) and higher porosity at the center (67 ± 8 to 75 ± 8%). The additives had varying effects on the pore sizes and permeabilities of the samples. ZnO yielded the most permeable scaffolds (5.92 × 10-11 m2), whereas nanohydroxyapatite yielded the scaffold with the lowest permeability (1.18 × 10-11 m2), values within the range reported for trabecular bone. The magnesium content had no statistically significant effect on the permeability. The best mechanical parameters were obtained for ZnO samples and those containing hydrated MgCl2. The scaffold's properties meet the criteria for filling osteochondral defects. The developed scaffolds follow a biomimetic approach in terms of hierarchical microarchitecture and mechanical parameters as well as chemical composition. The obtained composite materials have the potential as biomimetic scaffolds for the regeneration of osteochondral defects.
Asunto(s)
Hidrogeles , Cloruro de Magnesio , Andamios del Tejido , Óxido de Zinc , Óxido de Zinc/química , Andamios del Tejido/química , Cloruro de Magnesio/química , Hidrogeles/química , Porosidad , Alginatos/química , Durapatita/química , Permeabilidad , Gelatina/química , Ensayo de MaterialesRESUMEN
OBJECTIVES: To validate a mathematical model using porous media theory for alveolar CO2 determination in ventilated patients. DESIGN: Mathematical modeling study with prospective clinical validation to simulate CO2 exchange from bloodstream to airway entrance. SETTING: ICU. PATIENTS: Thirteen critically ill patients without chronic or acute lung disease. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Model outcomes compared with patient data showed correlations for end-tidal CO2 (EtCO 2 ), area under the CO2 curve, and Pa CO2 of 0.918, 0.954, and 0.995. Determination coefficients ( R2 ) were 0.843, 0.910, and 0.990, indicating precision and predictive power. CONCLUSIONS: The mathematical model shows potential in pulmonary critical care. Although promising, practical application demands further validation, clinician training, and patient-specific adjustments. The path to clinical use will be iterative, involving validation and education.
Asunto(s)
Dióxido de Carbono , Alveolos Pulmonares , Respiración Artificial , Humanos , Dióxido de Carbono/análisis , Masculino , Persona de Mediana Edad , Femenino , Estudios Prospectivos , Anciano , Alveolos Pulmonares/metabolismo , Unidades de Cuidados Intensivos , Adulto , Modelos Teóricos , Intercambio Gaseoso Pulmonar/fisiología , Enfermedad Crítica/terapia , PorosidadRESUMEN
Heterogeneous biocatalysts were prepared by adsorbing T. lanuginosus lipase (TLL) onto uncalcined (SBAUC-TLL) and calcined (SBAC-TLL) SBA-15, using ammonium fluoride as a pore expander to facilitate TLL immobilization. At an enzyme load of 1 mg/g, high immobilization yields (>90 %) and recovered activities (>80 % for SBAUC-TLL and 70 % for SBAC-TLL) were achieved. When increasing the enzyme load to 5 mg/g, the immobilization yield of SBAUC-TLL was 80 %, and the recovered activity was 50 %, while SBAC-TLL had a yield of 100 % and a recovered activity of 36 %. Crosslinking with glutaraldehyde (GA) was conducted to improve stability (SBAUC-TLL-GA and SBAC-TLL-GA). Although SBAC-TLL-GA lost 25 % of initial activity after GA modifications, it exhibited the highest thermal (t1/2 = 5.7 h at 65 °C), when compared to SBAC-TLL (t1/2 = 12 min) and the soluble enzyme (t1/2 = 36 min), and operational stability (retained 100 % activity after 5 cycles). Both biocatalysts presented high storage stability since they retained 100 % of initial activity for 30 days. These results highlight SBA-15's potential as an enzyme support and the protocol's efficacy in enhancing stability, with implications for industrial applications in the food, chemical, and pharmaceutical sectors.
Asunto(s)
Biocatálisis , Estabilidad de Enzimas , Enzimas Inmovilizadas , Lipasa , Dióxido de Silicio , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Lipasa/química , Lipasa/metabolismo , Dióxido de Silicio/química , Porosidad , Temperatura , Adsorción , Concentración de Iones de Hidrógeno , Eurotiales/enzimología , Cinética , Glutaral/químicaRESUMEN
Monoacylglycerols are eco-friendly and inexpensive emulsifiers with a range of applications. The traditional synthetic route is not eco-friendly, while enzymatic catalysis offers milder reaction conditions and higher selectivity. However, its application still is limited due to the costs. In this context, endophytic fungi can be source to new biocatalysts with enhanced catalytic activity. Based on this perspective, the aim of this study was perform the synthesis of MAG's through transesterification reactions of solketal and different vinyl esters, using crude and immobilized lipolytic extracts from the endophytic fungi Stemphylium lycopersici, isolated from Humiria balsamifera. The reactions were conducted using 100â mg of biocatalyst, 1â mmol of substrates, 9 : 1 n-heptane/acetone, at 40 °C, 200â rpm for 96 h. In the reactions using the ILE and stearate, laureate and decanoate vinyl esters it was possible to obtain the correspondent products with conversion rates of 52-75 %. Also, according to the structure drivers used in MCM-48 synthesis, different morphologies and conversions rates were observed. Employing [C16MI] Cl, [C14MI] Cl and [C4MI] Cl, the 1-lauroyl- glycerol conversion was 36 %, 79 % and 44 %, respectively. This is the first work involving the immobilization of an endophytic fungi and its utilization as a biocatalyst in the production of MAG's.
Asunto(s)
Biocatálisis , Monoglicéridos , Monoglicéridos/química , Monoglicéridos/metabolismo , Porosidad , Ascomicetos/metabolismoRESUMEN
Biosilica (BS) and spongin (SPG) from marine sponges are highlighted for their potential to promote bone regeneration. Moreover, 3D printing is introduced as a technology for producing bone grafts with optimized porous structures, allowing for better cell attachment, proliferation, and differentiation. Thus, this study aimed to characterize the BS and BS/SPG 3D printed scaffolds and to evaluate the biological effects in vitro. The scaffolds were printed using an ink containing 4 wt.% of sodium alginate. The physicochemical characteristics of BS and BS/SPG 3D printed scaffolds were analyzed by SEM, EDS, FTIR, porosity, evaluation of mass loss, and pH measurement. For in vitro analysis, the cellular viability of the MC3T3-E1 cell lineage was assessed using the AlamarBlue® assay and confocal microscopy, while genotoxicity and mineralization potential were evaluated through the micronucleus assay and Alizarin Red S, respectively. SEM analysis revealed spicules in BS, the fibrillar structure of SPG, and material degradation over the immersion period. FTIR indicated peaks corresponding to silicon oxide in BS samples and carbon oxide and amine in SPG samples. BS-SPG scaffolds exhibited higher porosity, while BS scaffolds displayed greater mass loss. pH measurements indicated a significant decrease induced by BS, which was mitigated by SPG over the experimental periods. In vitro studies demonstrated the biocompatibility and non-cytotoxicity of scaffold extracts. .Also, the scaffolds promoted cellular differentiation. The micronucleus test further confirmed the absence of genotoxicity. These findings suggest that 3D printed BS and BS/SPG scaffolds may possess desirable morphological and physicochemical properties, indicating in vitro biocompatibility.
Asunto(s)
Poríferos , Impresión Tridimensional , Andamios del Tejido , Animales , Andamios del Tejido/química , Poríferos/química , Ratones , Dióxido de Silicio/química , Regeneración Ósea , Porosidad , Supervivencia Celular , Ingeniería de Tejidos/métodos , Línea Celular , HuesosRESUMEN
SUMMARY: Tissue engineering aims to fabricate a scaffold that exhibits a suitable surface topography for a desired cellular response. Therefore, a study analyzing the characteristics of bone grafts is important for future research directions. This work aims to analyze the physical-chemical characteristics of commercially available bone grafts of human and bovine origin for dental use, using morphological analysis of the surface and chemical composition by variable pressure scanning electron microscope (VP-SEM) and energy-dispersive x-ray (EDX) spectrometry. In addition, pore diameter and surface area were analyzed by degassing method using a porosimeter, and particle size by laser diffraction. The analyzed allograft and xenograft particles differ in morphological characteristics and chemical composition. The allograft particles present a cuboidal and prismatic geometric morphology with angled edges and the absence of macropores. On the contrary, the xenograft particles present an irregular morphology with macropores in their structure. There is a statistically significant difference in C, P, and Ca between the xenograft and allografts (p < 0,05). The analyzed composition of allografts showed mainly the presence of C and O. In contrast, the composition of the xenograft was mainly Ca. These differences could influence the osteogenic properties of allografts and xenografts. This analysis provides basic information to understand the physicochemical properties of allografts and xenografts that facilitate cell-graft interaction.
La ingeniería de tejidos tiene como objetivo fabricar un andamio que muestre una topografía de superficie adecuada para una respuesta celular deseada. Por tanto, un estudio que analice las características de los injertos óseos es importante para futuros enfoques de investigación. Este trabajo tiene como objetivo analizar las características físico-químicas de injertos óseos de origen humano y bovino disponibles comercialmente para uso odontológico, mediante análisis morfológico de la superficie y composición química mediante microscopio electrónico de barrido de presión variable (VP-SEM) y x-dispersivo de energía. espectrometría de rayos (EDX). Además, el diámetro de los poros y el área superficial se analizaron mediante el método de desgasificación utilizando un porosímetro y el tamaño de las partículas mediante difracción láser. Las partículas de aloinjerto y xenoinjerto analizadas difieren en características morfológicas y composición química. Las partículas del aloinjerto presentan una morfología geométrica cúbica y prismática con bordes angulados y ausencia de macroporos. Por el contrario, las partículas de xenoinjerto presentan una morfología irregular con macroporos en su estructura. Existe una diferencia estadísticamente significativa en C, P y Ca entre el xenoinjerto y los aloinjertos (p < 0,05). La composición analizada de los aloinjertos mostró principalmente la presencia de C y O. Por el contrario, la composición del xenoinjerto fue principalmente Ca. Estas diferencias podrían influir en las propiedades osteogénicas de los aloinjertos y xenoinjertos. Este análisis proporciona información básica para comprender las propiedades fisicoquímicas de aloinjertos y xenoinjertos que facilitan la interacción célula-injerto.