RESUMEN

Hybrid diamond-like carbon (DLC) with incorporated titanium dioxide (TiO2) nanoparticle coatings have low friction coefficient, high wear resistance, high hardness, biocompatibility, and high chemical stability. They could be employed to modify biomedical alloys surfaces for numerous applications in biomedical engineering. Here we investigate for the first time the in vivo inflammatory process of DLC coatings with incorporated TiO2 nanoparticles. TiO2-DLC films were grown on AISI 316 stainless-steel substrates using plasma-enhanced chemical vapor deposition. The coated substrates were implanted in CF1 mice peritoneum. The in vivo cytotoxicity and biocompatibility of the samples were analyzed from macrophage lavage. Analysis in the first weeks after implantation could be helpful to evaluate the acute cytotoxicity generated after a possible inflammatory process. The in vivo results showed no inflammatory process. A significant increase in nitric oxide production on the uncoated substrates was confirmed through cytometry, and the coated substrates demonstrated biocompatibility. The presence of TiO2 nanoparticles enhanced the wound healing activity, due to their astringent and antimicrobial properties. DLC and TiO2-DLC coatings were considered biocompatible, and the presence of TiO2 nanoparticles reduced the inflammatory reactions, increasing DLC biocompatibility.

Asunto(s)

Carbono/química , Membranas Artificiales , Nanopartículas del Metal/química , Prótesis e Implantes , Titanio/química , Aleaciones , Animales , Carbono/farmacología , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/farmacología , Diamante/química , Dureza , Macrófagos Peritoneales/efectos de los fármacos , Macrófagos Peritoneales/fisiología , Ensayo de Materiales , Nanopartículas del Metal/uso terapéutico , Ratones , Acero Inoxidable/química , Acero Inoxidable/farmacología , Propiedades de Superficie , Titanio/farmacología

RESUMEN

Polycaprolactone (PCL) is a biocompatible, biodegradable synthetic polymer which in combination with nanohydroxyapatite (nHAp) can give rise to a low cost, nontoxic bioactive product with excellent mechanical properties and slow degradation. Here we produced, characterized and evaluated in vivo the bone formation of PCL/nHAp scaffolds produced by the rotary jet spinning technique. The scaffolds produced were firstly soaked into simulated body fluid for 21 days to also obtain nHAp onto PCL/nHAp scaffolds. Afterwards, the scaffolds were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy and Raman spectroscopy. For in vivo experiments, 20 male Wistar rats were used and randomly divided in 4 experimental groups (n = 5). A critical defect of 3 mm in diameter was made in the tibia of the animals, which were filled with G1 control (clot); G2-PCL scaffold; G3-PCL/nHAp (5%) scaffold; G4-PCL/nHAp (20%) scaffold. All animals were euthanized 60 days after surgery, and the bone repair in the right tibiae were evaluated by radiographic analysis, histological analysis and histomorphometric analysis. While in the left tibias, the areas of bone repair were submitted to the flexural strength test. Radiographic and histomorphometric analyses no showed statistical difference in new bone formation between the groups, but in the three-point flexural tests, the PCL/nHAp (20%) scaffold positively influenced the flexural mode of the neoformed bone. These findings indicate that PCL/nHAp (20%) scaffold improve biomechanical properties of neoformed bone and could be used for bone medicine regenerative.

Asunto(s)

Líquidos Corporales/química , Durapatita/química , Resistencia Flexional , Osteogénesis , Poliésteres/química , Andamios del Tejido/química , Animales , Fenómenos Biomecánicos/efectos de los fármacos , Líquidos Corporales/fisiología , Regeneración Ósea/efectos de los fármacos , Sustitutos de Huesos/síntesis química , Sustitutos de Huesos/química , Sustitutos de Huesos/farmacología , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/farmacología , Durapatita/farmacología , Resistencia Flexional/efectos de los fármacos , Resistencia Flexional/fisiología , Fracturas Óseas/fisiopatología , Fracturas Óseas/terapia , Regeneración Tisular Dirigida/instrumentación , Regeneración Tisular Dirigida/métodos , Masculino , Ensayo de Materiales , Nanoestructuras/química , Osteogénesis/efectos de los fármacos , Poliésteres/farmacología , Polímeros/síntesis química , Polímeros/química , Polímeros/farmacología , Ratas , Ratas Wistar , Estrés Mecánico , Tibia/patología , Ingeniería de Tejidos/instrumentación , Ingeniería de Tejidos/métodos

RESUMEN

Over the past few years, several tridimensional synthetic bone grafts, known as scaffolds, are being developed to overcome the autologous grafts limitations. Among the materials used on the production of scaffolds, the 45S5 bioglass stands out due to its capacity of bonding to hard and soft tissues. Silver nanoparticles are well-known for their antimicrobial properties and their incorporation on the scaffold may promote its antimicrobial response, avoiding microorganism proliferation on the materials surface. This study proposes a simple way to coat 45S5 bioglass-based scaffolds with silver nanoparticles. The scaffolds were obtained by the sponge replication technique and the silver nanoparticles were incorporated by soaking under ultrasonic stirring. The antimicrobial activity of the scaffolds was analyzed against three different microbial strains: S. aureus, P. aeruginosa, and C. albicans. Due to the heat treatment during the scaffold production, the bioglass crystalized mainly in a sodium calcium silicate phase, forming a glass-ceramic scaffold. The silver nanoparticles were coated in a well-distributed manner throughout the scaffold, while avoiding their aggregation. The coated scaffold inhibited the growth of all the analyzed microorganism. Therefore, the use of ultrasonic stirring to coat the bioglass scaffold with silver nanoparticles showed to be an efficient way to promote its antimicrobial response.

Asunto(s)

Antiinfecciosos , Candida albicans/crecimiento & desarrollo , Materiales Biocompatibles Revestidos , Vidrio/química , Nanopartículas del Metal/química , Pseudomonas aeruginosa/crecimiento & desarrollo , Plata/química , Staphylococcus aureus/crecimiento & desarrollo , Antiinfecciosos/síntesis química , Antiinfecciosos/química , Antiinfecciosos/farmacología , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/farmacología

Asunto(s)

Anillo Fibroso/metabolismo , Materiales Biocompatibles Revestidos/síntesis química , Poliuretanos/síntesis química , Adhesivos Tisulares/síntesis química , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Materiales Biocompatibles Revestidos/administración & dosificación , Materiales Biocompatibles Revestidos/metabolismo , Colágeno/química , Haplorrinos , Inyecciones , Cinética , Fenómenos Mecánicos , Ratones , Cemento de Policarboxilato/química , Poliuretanos/administración & dosificación , Poliuretanos/metabolismo , Propiedades de Superficie , Temperatura , Termodinámica , Adherencias Tisulares/metabolismo , Adhesivos Tisulares/administración & dosificación , Adhesivos Tisulares/metabolismo , Viscosidad

RESUMEN

Carbon Nanotubes (CNTs) are considered alternative materials for the design of advanced drug and gene delivery vectors. However, the mechanism responsible for the cellular membrane intake of CNTs is not well understood. In the present study, we show how multi-walled carbon nanotubes (MWCNTs) owning different surface properties, interact with giant unilamellar vesicles (GUVs), a simple model system for cellular membranes. In particular, we want to address the hydrophilic/hydrophobic interactions between MWCNTs and lipid membranes and the subsequent mechanical properties changes of the systems. In order to elucidate this interaction, we made the following chemical modifications on MWCNTs: oxidized MWCNTs (ox-MWCNTs) displaying reduced hydrophobic surface character, pristine MWCNTs (p-MWCNTs), and alkyl functionalized MWCNTs (alk-MWCNTs) exhibiting enhanced hydrophobic surface properties, were put in contact with GUVs and observed by confocal microscopy. Our observations revealed that the interaction between the CNTs and GUVs depends on the type of chemical functionalization: ox-MWCNTs remain at the membrane interacting with the polar head of the phospholipids, p-MWCNTs internalize GUVs spontaneously, and alk-MWCNTs persist inside the membrane. The mechanical properties of MWCNTs@GUVs systems were measured using the electrodeformation method, which shows an increased bending stiffness (κ) of the GUVs as MWCNTs concentration increases. High concentrations of p-MWCNTs and alk-MWCNTs induced vesicle adhesion; p-MWCNTs produced a considerable reduction in the average size of the GUVs, while alk-MWCNTs form complex stable structures inside the membrane. The statistical analyses of the experimental results are compared with available computer simulations. The picture emerging from our results is that the interaction between GUVs and MWCNTs is due mainly to hydrophobicity.

Asunto(s)

Membrana Celular , Membranas Artificiales , Modelos Biológicos , Nanotubos de Carbono/química , Fosfolípidos/química , Membrana Celular/patología , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/química , Interacciones Hidrofóbicas e Hidrofílicas , Ensayo de Materiales , Fenómenos Mecánicos , Propiedades de Superficie

RESUMEN

The purpose of this work was to investigate the influence of acid treatment on the surface properties and in vivo performance of titanium grade 5 (Ti6Al4V) alloy. Mini-implants with surface treatment were inserted into New Zealand rabbit tibia for 1, 4 and 8 weeks. SEM analysis showed intercommunicated micropores in acid treated samples. AFM showed micron and sub-micron roughness. The thickness of the titanium oxide layer increased with surface treatment, with a significant reduction of Al and V concentration. Acid treated implant removal torque was larger than without treatment. The implants/bone interface of acid treated implants showed dense adhered Ca/P particles with spreading osteoblasts after 4 weeks and newly formed bone trabeculae after 8 weeks. Analysis of rabbit blood that received treated implant showed lower Al and V contents at all times. Acid treatment improved surface morphology and mechanical stability, which allowed initial events of osseointegration, while Al-V ion release was reduced. GRAPHICAL ABTSRACT.

Asunto(s)

Materiales Biomédicos y Dentales , Materiales Biocompatibles Revestidos/química , Ácido Clorhídrico/farmacología , Implantes Experimentales , Titanio/química , Aleaciones , Animales , Materiales Biomédicos y Dentales/síntesis química , Materiales Biomédicos y Dentales/química , Tornillos Óseos , Interfase Hueso-Implante , Materiales Biocompatibles Revestidos/síntesis química , Implantación Dental Endoósea/instrumentación , Implantes Dentales , Femenino , Oseointegración , Porosidad/efectos de los fármacos , Conejos , Propiedades de Superficie/efectos de los fármacos

RESUMEN

Surface characteristics can mediate biological interaction improving or affecting the tissue integration after implantation of a biomaterial. Features such as topography, wettability, surface energy and chemistry can be key determinants for interactions between cells and materials. Plasma electrolytic oxidation (PEO) is a technique used to control this kind of parameters by the addition of chemical species and the production of different morphologies on the surfaces of titanium and its alloys. With the purpose to improve the biological response, surfaces of c.p titanium and Ti6Al4V were modified by using PEO. Different electrolytes, voltages, current densities and anodizing times were tested in order to obtain surfaces with different characteristics. The obtained materials were characterized by different techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and glow discharge optical emission spectroscopy (GDOES). Wettability of the obtained surfaces were measured and the corresponding surface energies were calculated. Superhydrophilic surfaces with contact angles of about 0 degrees were obtained without any other treatment but PEO and this condition in some cases remains stable after several weeks of anodizing; crystal phase composition (anatase-rutile) of the anodic surface appears to be critical for obtaining this property. Finally, in order to verify the biological effect of these surfaces, osteoblast were seeded on the samples. It was found that cell behavior improves as SFE (surface free energy) and coating porosity increases whereas it is affected negatively by roughness. Techniques for surface modification allow changes in the coatings such as surface energy, roughness and porosity. As a consequence of this, biological response can be altered. In this paper, surfaces of c.p Ti and Ti6Al4V were modified by using plasma electrolytic oxidation (PEO) in order to accelerate the cell adhesion process.

Asunto(s)

Materiales Biocompatibles Revestidos/síntesis química , Electrólitos/química , Galvanoplastia/métodos , Andamios del Tejido/química , Titanio/química , Aleaciones , Células Cultivadas , Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/farmacología , Humanos , Ensayo de Materiales , Osteoblastos/citología , Osteoblastos/efectos de los fármacos , Osteoblastos/fisiología , Oxidación-Reducción , Propiedades de Superficie , Titanio/farmacología , Humectabilidad

RESUMEN

This study was designed to apply (super)hydrophobic crosslinked coatings by means of a sol-gel process on the surface of orthodontic devices and investigate the potential effect of these coatings in reducing the early retention of oral biofilm. Two organosilane-based hydrophobic solutions (HSs) were prepared containing hexadecyltrimethoxysilane diluted in ethanol (HS1) or 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane diluted in dimethyl sulfoxide (HS2). Stainless steel plates and ceramic discs were coated with HS1 or HS2 and heated at 150 °C for 2 h for condensation of a crosslinked SiO x network. Organosilane coatings were applied after previous, or no, surface sandblasting. Commercial stainless steel and ceramic brackets were used to evaluate oral biofilm retention after 12 h or 24 h of biofilm growth, using a microcosm model with human saliva as the inoculum. Surface roughness analysis (Ra, µm) indicated that sandblasting associated with organosilane coatings increased roughness for stainless steel brackets only. Analysis of the water contact angle showed that the stainless steel surface treated with HS1 was hydrophobic (~123°), while the ceramic surface treated with HS2 was superhydrophobic (~155°). Biofilm retention after 24 h was significantly lower in groups treated with hydrophobic coatings. An exponential reduction in biofilm accumulation was associated with increased water contact angle for both stainless steel and ceramic at 24 h. Application of (super)hydrophobic coatings on the surface of stainless steel and ceramic orthodontic devices might reduce the retention of oral biofilm.

Asunto(s)

Antibacterianos/administración & dosificación , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Materiales Biocompatibles Revestidos/administración & dosificación , Boca/microbiología , Aparatos Ortodóncicos/microbiología , Antibacterianos/síntesis química , Materiales Biocompatibles Revestidos/síntesis química , Diseño de Equipo , Análisis de Falla de Equipo , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Ensayo de Materiales , Boca/efectos de los fármacos , Propiedades de Superficie

RESUMEN

The layer-by-layer technique has been used as a powerful method to produce multilayer thin films with tunable properties. When natural polymers are employed, complicated phenomena such as self-aggregation and fibrilogenesis can occur, making it more difficult to obtain and characterize high-quality films. The weak acid and base character of such materials provides multilayer systems that may differ from those found with synthetic polymers due to strong self-organization effects. Specifically, LbL films prepared with chitosan and silk fibroin (SF) often involve the deposition of fibroin fibrils, which can influence the assembly process, surface properties, and overall film functionality. In this case, one has the intriguing possibility of realizing multilayer thin films with aligned nanofibers. In this article, we propose a strategy to control fibroin fibril formation by adjusting the assembly partner. Aligned fibroin fibrils were formed when chitosan was used as the counterpart, whereas no fibrils were observed when poly(allylamine hydrochloride) (PAH) was used. Charge density, which is higher in PAH, apparently stabilizes SF aggregates on the nanometer scale, thereby preventing their organization into fibrils. The drying step between the deposition of each layer was also crucial for film formation, as it stabilizes the SF molecules. Preliminary cell studies with optimized multilayers indicated that cell viability of NIH-3T3 fibroblasts remained between 90 and 100% after surface seeding, showing the potential application of the films in the biomedical field, as coatings and functional surfaces.

Asunto(s)

Materiales Biocompatibles Revestidos/síntesis química , Fibroínas/síntesis química , Nanofibras/química , Seda/síntesis química , Animales , Bombyx , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Materiales Biocompatibles Revestidos/farmacología , Fibroínas/farmacología , Ratones , Células 3T3 NIH , Nanofibras/administración & dosificación , Seda/farmacología , Propiedades de Superficie

RESUMEN

Infection is the most common factor that leads to dental titanium implant failure. Antibacterial implant surfaces based on nano-scale modifications of the titanium appear as an attractive strategy for control of peri-implantitis. In the present work, the preparation and antibacterial properties of a novel composite coating for titanium based on nanoporous silica and silver nanoparticles are presented. Starch-capped silver nanoparticles (AgNPs) were synthesized and then incorporated into sol-gel based solution system. The AgNP-doped nanoporous silica coatings were prepared on titanium surface using a combined sol-gel and evaporation-induced self-assembly (EISA) method. The coating nanostructure was characterized by XRD, SEM-EDX, and HR-TEM. Antibacterial activity was evaluated against Aggregatibacter actinomycetemcomitans, a representative pathogen of dental peri-implantitis. Colony-forming units (CFUs) were counted within the biofilm and at the planktonic state. Biofilm development was quantified using crystal violet staining and viability of adherent bacteria was confirmed with the Live/Dead fluorescence assay. Silica-based composite coating containing AgNPs (AgNP/NSC) was prepared on titanium surface by direct incorporation of AgNP suspension into the sol-gel system. The self-assembly technique enabled the spontaneous formation of a highly ordered nanoporosity in the coating structure, which is a desired property for osseointegration aspects of titanium implant surface. AgNP/NSC coating produces a strong antibacterial effect on titanium surface by not only killing the adherent bacteria but also reducing the extent of biofilm formation. Biofilm survival is reduced by more than 70% on the AgNP/NSC-modified titanium surface, compared to the control. This antibacterial effect was verified for up to 7 days of incubation. The long-term antibacterial activity exhibited by the nanostructured AgNP/NSC-titanium surface against A. actinomycetemcomitans suggests that this type of nano-scale surface modification is a promissory strategy to control infections associated with dental implant rehabilitation.

Asunto(s)

Antibacterianos/síntesis química , Materiales Biocompatibles Revestidos/síntesis química , Nanopartículas del Metal/química , Dióxido de Silicio/química , Plata/química , Titanio/química , Aggregatibacter actinomycetemcomitans/efectos de los fármacos , Aggregatibacter actinomycetemcomitans/fisiología , Antibacterianos/química , Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/farmacología , Implantes Dentales , Geles/química , Nanoporos , Plata/metabolismo , Propiedades de Superficie , Difracción de Rayos X

RESUMEN

Avian influenza viruses preferentially bind to sialic acid alpha-2,3-galactose (N-SA-α-2,3-Gal) receptors on epithelial cells. Herein, we describe a procedure we have developed for isolation of N-SA-α-2,3-Gal receptors from porcine trachea using magnetic nanoparticles (NPs) coated with chitosan (NP-Ch) and functionalized with Maackia amurensis lectin (NP-lectin). Magnetic nanoparticles were coated with chitosan in a one-step co-precipitation, and then M. amurensis lectin was immobilized covalently using glutaraldehyde. Lectin coated nanoparticles were incubated with sialic acid enriched fraction of tracheal homogenate, and N-SA-α-2,3-Gal receptor was extracted under magnetic field in two cycles. The presence of 66.4 kDa protein was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The interaction of immobilized receptor (NP-Ch-R) with M. amurensis lectin (NP-Ch-R-L) was demonstrated by Fourier transform infrared spectrometry (FTIR) and thermogravimetric analysis (TGA).

Asunto(s)

Quitosano/química , Maackia/química , Nanopartículas de Magnetita/química , Lectinas de Plantas/química , Receptores de Superficie Celular/aislamiento & purificación , Tráquea/química , Animales , Materiales Biocompatibles Revestidos/síntesis química , Separación Inmunomagnética/métodos , Campos Magnéticos , Nanopartículas de Magnetita/efectos de la radiación , Nanopartículas de Magnetita/ultraestructura , Orthomyxoviridae/metabolismo , Tamaño de la Partícula , Receptores de Superficie Celular/metabolismo , Porcinos

RESUMEN

Composites prepared from polyaniline (PANI) and the ceramic technology of titanium dioxide (TiO2) have been proposed, however, the interaction of these materials with greater control of molecular arrangement becomes attractive in order to achieve properties not previously described or yet the optimization of those already reported. Therefore, in this study, thin hybrid films made of polyaniline (PANI), a conductive polymer, and the technological ceramic, titanium dioxide (TiO2), were prepared by the layer-by-layer (LbL) self-assembly technique. The films were characterized by cyclic voltammetry (CV), UV-VIS spectroscopy and atomic force microscopy (AFM). Aiming to improve the dispersion of the ceramic in the polymer matrix, the commercial surfactant, cetyl trimethylammonium bromide (CTAB), was used in the formation of the films. The best condition of deposition was found showing synergic interactions between the conjugated materials. The antibacterial activity of the PANI(TiO2)/CTAB films was studied and the obtained results suggest their use as antimicrobial coatings.

Asunto(s)

Compuestos de Anilina/química , Compuestos de Anilina/farmacología , Compuestos de Cetrimonio/química , Compuestos de Cetrimonio/farmacología , Membranas Artificiales , Staphylococcus aureus/fisiología , Titanio/química , Antibacterianos/síntesis química , Antibacterianos/farmacología , Supervivencia Celular/efectos de los fármacos , Cetrimonio , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/farmacología , Ensayo de Materiales , Staphylococcus aureus/efectos de los fármacos , Titanio/farmacología

RESUMEN

Silver nanoparticles are widely used due to their biomedical-antibacterial applications. At the same time, the stabilization of these nanoparticles is challenging and may be made using polymeric carbohydrates, based on the practice of avoiding toxic chemicals and undesirable residues. In this study, we synthesized silver nanoparticles (AgNPs) which were stabilized by carbohydrates (potato starch and chitosan) and characterized by UV-Vis spectroscopy, zeta potential and transmission electron microscopy techniques. Bactericidal efficiency of AgNPs capped with different carbohydrates was tested demonstrating that the synthesized materials were able to inhibit the growth of two clinical/medical relevant bacteria strains (Escherichia coil and Staphylococcus aureus). AgNPs stabilized by chitosan presented enhanced bactericidal activity if compared to the ones synthesized in presence of potato starch. This difference is mainly attributed to the known antibacterial properties of chitosan associated to overall positive charge of the nanoparticles capped by this polymer. Those nanoparticles obtained in presence of starch presented minor bactericidal effects since the starch-capping agent is not able to contribute to the avoidance of bacteria growth and confers a quasi-neutral charge to the nanoparticle.

Asunto(s)

Fenómenos Fisiológicos Bacterianos/efectos de los fármacos , Carbohidratos/química , Nanopartículas del Metal/administración & dosificación , Nanopartículas del Metal/química , Nanocápsulas/administración & dosificación , Nanocápsulas/química , Plata/administración & dosificación , Antibacterianos/administración & dosificación , Antibacterianos/química , Supervivencia Celular/efectos de los fármacos , Materiales Biocompatibles Revestidos/síntesis química , Ensayo de Materiales , Plata/química , Electricidad Estática

RESUMEN

The investigation of titanium (Ti) surface modifications aiming to increase implant osseointegration is one of the most active research areas in dental implantology. This study was carried out to evaluate the benefits of coating Ti with type I collagen on the osseointegration of dental implants. Acid etched Ti implants (AETi), either untreated or coated with type I collagen (ColTi), were placed in dog mandibles for three and eight weeks for histomorphometric, cellular and molecular evaluations of bone tissue response. While the histological aspects were essentially the same with both implants being surrounded by lamellar bone trabeculae, histomorphometric analysis showed more abundant bone formation in ColTi, mainly at three weeks. Cellular evaluation showed that cells harvested from bone fragments in close contact with ColTi display lower proliferative capacity and higher alkaline phosphatase activity, phenotypic features associated with more differentiated osteoblasts. Confirming these findings, molecular analyses showed that ColTi implants up-regulates the expression of a panel of genes well known as osteoblast markers. Our results present a set of evidences that coating AETi with collagen fastens the osseointegration by stimulating bone formation at the cellular and molecular levels, making this combination of morphological and biochemical modification a promising approach to treat Ti surfaces.

Asunto(s)

Materiales Biocompatibles Revestidos/síntesis química , Colágeno Tipo I/química , Implantes Dentales , Mandíbula/patología , Mandíbula/cirugía , Oseointegración/fisiología , Titanio/química , Animales , Materiales Dentales/síntesis química , Perros , Mandíbula/fisiología

RESUMEN

In this work, didecyldimethylammonium bromide (DDAB) and 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) (2.5:1) were used to prepare liposomes coated with polyacrylic acid (PAA) using "in situ" polymerization with 2.5, 5 and 25 mM of acrylic acid (AA). The PAA concentrations were chosen to achieve partially to fully covered capsules, and the polymerization reaction was observed with real-time monitoring using dynamic light scattering (NanoDLS). The DDAB:DOPE liposomes showed stability in the tested temperature range (25-70°C), whereas the results confirmed the success of the polymerization according to superficial charge (zeta potential of +66.7±1.2 mV) results and AFM images. For the liposomes that were fully coated with PAA (zeta potential of +0.3±3.9 mV), cytotoxicity was independent of the concentration of albumin. Cationic liposomes and nanocapsules of the stable liposomes coated with PAA were obtained by controlling the surface charge, which was the most important factor related to cytotoxicity. Thus, a potential, safe drug nanocarrier was successfully developed in this work.

Asunto(s)

Supervivencia Celular/efectos de los fármacos , Materiales Biocompatibles Revestidos/síntesis química , Portadores de Fármacos/síntesis química , Liposomas/química , Nanocápsulas/química , Células 3T3 , Resinas Acrílicas/química , Animales , Cationes/química , Materiales Biocompatibles Revestidos/metabolismo , Materiales Biocompatibles Revestidos/farmacología , Portadores de Fármacos/metabolismo , Portadores de Fármacos/farmacología , Luz , Liposomas/metabolismo , Liposomas/farmacología , Liposomas/ultraestructura , Ratones , Microscopía de Fuerza Atómica , Nanocápsulas/ultraestructura , Fosfatidiletanolaminas/química , Polimerizacion , Compuestos de Amonio Cuaternario/química , Reología/efectos de los fármacos , Dispersión de Radiación , Electricidad Estática

RESUMEN

Protecting metallic implants from the harsh environment of physiological fluids is essential to guaranteeing successful long-term use in a patient's body. Chemical degradation may lead to the failure of an implant device in two different ways. First, metal ions may cause inflammatory reactions in the tissues surrounding the implant and, in extreme cases, these reactions may inflict acute pain on the patient and lead to loosening of the device. Therefore, increasing wear strength is beneficial to the performance of the metallic implant. Second, localized corrosion processes contribute to the nucleation of fatigue cracks, and corrosion fatigue is the main reason for the mechanical failure of metallic implants. Common biomedical alloys such as stainless steel, cobalt-chrome alloys, and titanium alloys are prone to at least one of these problems. Vapor-deposited hard coatings act directly to improve corrosion, wear, and fatigue resistances of metallic materials. The effectiveness of the corrosion protection is strongly related to the structure of the physical vapor deposition layer. The aim of this paper is to present a comprehensive review of the correlation between the structure of physical vapor deposition layers and the corrosion properties of metallic implants.

Asunto(s)

Materiales Biocompatibles Revestidos/síntesis química , Corrosión , Gases/química , Metales/química , Prótesis e Implantes

RESUMEN

An analysis was carried out to observe whether the application or not of a composite surface sealant (CSS), as well the moment for CSS application were able to reduce marginal microleakage in compactable composite resin restoration. All the preparations were restored with a compactable composite resin. The restored teeth were randomly assessed. G1 (control group): finished and polished; G2: finished, polished, etched and cover with CSS; G3: immediately after the restoration done the CSS was applied, then finished and polished; G4: CSS applied immediately after the restoration was done, the finished and polished, etched, and covered with CSS. The specimens were isolated with nail polish, thermocycled, immersed in aqueous solution of silver nitrate, and followed in a photo developing solution. The microleakage scores obtained from the occlusal and cervical walls were analyzed with the Kruskall-Wallis nonparametric test. No microleakage was found at the enamel margins. Comparing the microleakage scores at dentin/cementum margins (p < 0.05) it was found that G3 (p = 0.0162) and G4 (p = 0.0187) were able to reduce microleakage when compared with group G2. However the results were not statistically different from the control group. The application of CSS was not able to completely eliminate marginal microleakage at the dentin/cementum margins.

Asunto(s)

Materiales Biocompatibles Revestidos/síntesis química , Resinas Compuestas/síntesis química , Materiales Dentales/síntesis química , Selladores de Fosas y Fisuras/farmacología , Resinas Compuestas/química , Preparación de la Cavidad Dental/métodos , Esmalte Dental/efectos de los fármacos , Filtración Dental/prevención & control , Materiales Dentales/química , Restauración Dental Permanente , Recubrimientos Dentinarios/farmacología , Humanos , Propiedades de Superficie/efectos de los fármacos , Factores de Tiempo

RESUMEN

A polypeptide chain formed by recombinant antigens, cytoplasmic repetitive antigen (CRA) and flagellar repetitive antigen (FRA) (CF-Chimera) of Trypanosoma cruzi, was adsorbed on gold and platinum electrodes and investigated by electrochemical impedance spectroscopy on phosphate buffer saline solutions (PBS) containing a redox couple. It was found that the adsorption is strongly sensitive to the oxide layer on the electrode surface. In the majority of the experiments the antigens retained their activity as observed through their interaction with sera from chronic chagasic patients. The results expressed in terms of the charge transfer resistance across the interface, indicate the viability of using the impedance methodology for the development of a biosensor for serological diagnosis of Chagas' disease.

Asunto(s)

Anticuerpos/sangre , Complejo Antígeno-Anticuerpo/sangre , Técnicas Biosensibles/instrumentación , Enfermedad de Chagas/sangre , Enfermedad de Chagas/diagnóstico , Impedancia Eléctrica , Electrodos , Inmunoensayo/instrumentación , Anticuerpos/inmunología , Complejo Antígeno-Anticuerpo/inmunología , Técnicas Biosensibles/métodos , Enfermedad de Chagas/inmunología , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/química , Electroquímica/instrumentación , Electroquímica/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Oro , Humanos , Inmunoensayo/métodos , Metales , Platino (Metal) , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Pruebas Serológicas/instrumentación , Pruebas Serológicas/métodos

RESUMEN

The total and partially purified enzyme pectinmethylesterase from acerola fruit was covalently immobilized on porous silica particles. These efficiency values were 114% for the total PME and 351% for the partially purified PME. In both forms the immobilization resulted in compounds with high thermal stability.

Asunto(s)

Hidrolasas de Éster Carboxílico/química , Hidrolasas de Éster Carboxílico/metabolismo , Materiales Biocompatibles Revestidos/síntesis química , Malpighiaceae/enzimología , Dióxido de Silicio/química , Hidrolasas de Éster Carboxílico/aislamiento & purificación , Materiales Biocompatibles Revestidos/química , Activación Enzimática , Estabilidad de Enzimas , Enzimas Inmovilizadas/química , Calor , Concentración de Iones de Hidrógeno , Malpighiaceae/química , Membranas Artificiales , Porosidad , Temperatura

RESUMEN

Pure and composite nanostructured films of conducting polymers were used as individual sensing units constituting an electronic tongue. The use of extremely thin films for signal transduction via impedance spectroscopy measurements in the frequency range 10-1 MHz allows the detection of trace amounts of tastants and inorganic contaminants in liquid systems. In addition, the sensor could detect the suppression of sourness by sweetness displaying similarities with the biological system. Brands of several commercial beverages could be easily distinguished without complex analysis, including the discrimination of waters, tastants and wines.

Asunto(s)

Biomimética/métodos , Análisis de los Alimentos/métodos , Membranas Artificiales , Microquímica/métodos , Polímeros/química , Análisis Espectral/métodos , Gusto , Transductores , Bebidas/análisis , Biomimética/instrumentación , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/química , Conductividad Eléctrica , Impedancia Eléctrica , Electroquímica/instrumentación , Electroquímica/métodos , Estudios de Factibilidad , Análisis de los Alimentos/instrumentación , Ácido Clorhídrico/análisis , Microquímica/instrumentación , Nanotecnología/instrumentación , Nanotecnología/métodos , Polímeros/síntesis química , Quinina/análisis , Sensibilidad y Especificidad , Cloruro de Sodio/análisis , Sacarosa/análisis