MTA HP Repair stimulates in vitro an homogeneous calcium phosphate phase coating deposition

To study the mineralization capacity in vitro of the bioceramic endodontic material MTA HP Repair. Bioactivity evaluation in vitro was carried out, by soaking processed cement disk in simulated body fluid (SBF) during 168 h. The cement surface was studied by Fourier transform infrared spectroscopy (FT-IR), field emission gun scanning electron microscopy (FEG-SEM) and energy dispersive X-ray analysis (EDX). Release to the SBF media of ionic degradation products was monitored using inductively coupled plasma atomic emission spectroscopy (ICP-AES). FT-IR showed increasing formation of phosphate phase bands at 1097, 960, 607 and 570 cm-1 with prolonged SBF soaking. FEG-SEM analysis reveals that HP produces a effectively surface covering consisting in homogeneous spherical phosphate phase aggregates with an average diameter of 0.5-1.0 µm. EDX analysis comparing un-treated (hydrated), 24 h and 72 h SBF treated surfaces of MTA HP Repair revealed phosphate deposition after 24 h, with high phosphorous/silicon element ratio signal measured after 24 h, indicating a very high phosphate phase deposition for this material. The study shows that MTA HP Repair produces a quick and effective bioactive response in vitro in terms of crystalline calcium phosphate surface coating formation. The high bioactive response of MTA HP Repair makes it an interesting candidate for endodontic use as repair cement

Determination of pore size distribution at the cell-hydrogel interface

<p>Abstract</p> <p>Background</p> <p>Analyses of the pore size distribution in 3D matrices such as the cell-hydrogel interface are very useful when studying changes and modifications produced as a result of cellular growth and proliferation within the matrix, as pore size distribution plays an important role in the signaling and microenvironment stimuli imparted to the cells. However, the majority of the methods for the assessment of the porosity in biomaterials are not suitable to give quantitative information about the textural properties of these nano-interfaces.</p> <p>Findings</p> <p>Here, we report a methodology for determining pore size distribution at the cell-hydrogel interface, and the depth of the matrix modified by cell growth by entrapped HepG₂cells in microcapsules made of 0.8% and 1.4% w/v alginate. The method is based on the estimation of the shortest distance between two points of the fibril-like network hydrogel structures using image analysis of TEM pictures. Values of pore size distribution determined using the presented method and those obtained by nitrogen physisorption measurements were compared, showing good agreement. A combination of these methodologies and a study of the cell-hydrogel interface at various cell culture times showed that after three days of culture, HepG₂cells growing in hydrogels composed of 0.8% w/v alginate had more coarse of pores at depths up to 40 nm inwards (a phenomenon most notable in the first 20 nm from the interface). This coarsening phenomenon was weakly observed in the case of cells cultured in hydrogels composed of 1.4% w/v alginate.</p> <p>Conclusions</p> <p>The method purposed in this paper allows us to obtain information about the radial deformation of the hydrogel matrix due to cell growth, and the consequent modification of the pore size distribution pattern surrounding the cells, which are extremely important for a wide spectrum of biotechnological, pharmaceutical and biomedical applications.</p

Physicochemical parameters - hydration performance relationship of the new endodontic cement MTA Repair HP

To characterize the chemical composition and textural parameters of the MTA Repair HP precursor powder and their influence to hydration performance. Un-hydrated precursor material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray fluorescence (XRF), laser diffraction (LD), N2 physisorption and field emission gun scanning electron microscopy (FEG-SEM). Setting time was assessed according to ASTM specification C 266. Hydrated material was analysed by XRD, FT-IR, energy dispersive X-ray (EDX) analysis and FEG-SEM. Ca3SiO5 and Ca2SiO4, in addition to CaWO4 as radiopacifier are the main compositional phases. Other measured parameter indicates high specific surface area of 4.8 m2 g-1, high aluminium content of 1.7 wt.% and low initial and final setting times of 12 and 199 min, respectively. Singular microstructural features consisting of high aspect ratio nanoparticles are main constituents of un-hydrated precursor. Besides, FEM-SEM observation shows notably growth of hexagonal shaped plate-like morphologies homogeneously distributed along the sample during hydration process. The short setting time measured for HP Repair, is correlated with high surface area of precursor powder, high Al content and the absence of compositional sulphate phases

Nanofibrous gelatin-based biomaterial with improved biomimicry using D-periodic self-assembled atelocollagen

Design of bioinspired materials that mimic the extracellular matrix (ECM) at the nanoscale is a challenge in tissue engineering. While nanofibrillar gelatin materials mimic chemical composition and nano-architecture of natural ECM collagen components, it lacks the characteristic D-staggered array (D-periodicity) of 67 nm, which is an important cue in terms of cell recognition and adhesion properties. In this study, a nanofibrous gelatin matrix with improved biomimicry is achieved using a formulation including a minimal content of D-periodic self-assembled atelocollagen. We suggest a processing route approach consisting of the thermally induced phase separation of the gelatin based biopolymeric mixture precursor followed by chemical-free material cross-linking. The matrix nanostructure is characterized using field emission gun scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM), wide angle X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). The cell culture assays indicate that incorporation of 2.6 wt.% content of D-periodic atelocollagen to the gelatin material, produces a significant increase of MC3T3-E1 mouse preosteoblast cells attachment and human mesenchymal stem cells (hMSCs) proliferation, in comparison with related bare gelatin matrices. The presented results demonstrate the achievement of an efficient route to produce a cost-effective, compositionally defined and low immunogenic “collagen-like” instructive biomaterial, based on gelatin

Bone Deleterious Effects of Different NRTIs in Treatment-naïve HIV Patients After 12 and 48 Weeks of Treatment

Background: Bone alterations have been observed in the course of HIV infection, char-acterized by a marked decrease in bone mineral density (BMD) and an increase in the frequency of fractures as a result of fragility. We aim to evaluate early changes in bone metabolic profile and the possible association with tenofovir and other nucleoside and nucleotide reverse transcriptase inhibi-tors (NRTIs) in treatment-naïve HIV patients. Methods: We conducted a prospective study in naïve HIV-infected adults (under 50 years), separat-ed into three groups according to NRTI therapy: tenofovir disoproxil fumarate (TDF); tenofovir alafenamide (TAF) and abacavir (ABC). BMD and epidemiological, immunological and metabolic bone parameters were evaluated. Bone markers were analyzed in plasma at baseline, 12 and 48 weeks after initiating treatment. Results: Average age of patients was 34.8 years (± 9.6). 92.4% of them with CD4 count > 200 cel/μL. At week 12 after starting treatment, both TDF [increase in PN1P (31.7%, p = 0.004), TRAP (11.1%, p = 0.003), OPN (19.3%, p = 0.045) and OC (38.6%, p = 0.001); decrease in OPG (-23.4%, p = 0.003)] and TAF [increase in 42.6% for CTX (p = 0.011), 27.3% for OC (p = 0.001) and 21% for TRAP (p = 0.008); decrease in OPG (-28.8%, p = 0.049)] presented a deep resorption profile compared to ABC, these differences in bone molecular markers, a tendency to equalize at week 48, where no significant differences were observed. Patients treated with TDF showed the greatest decrease in Z-score in both lumbar spine (LS) and femoral neck (FN) at week 48 without statistically significant differences. Conclusion: Treatment-naïve HIV patients have a high prevalence of low bone density. Treatment with TDF is associated with greater bone deterioration at 12 and 48 weeks. TAF seems to present similar early bone deterioration at 12 weeks which disappears at 48 weeks.This research was financially supported by The Carlos III Health Institute through the “Miguel Servet” program (CP15/00053), co-funded by The European Regional Development Fund and research grants from the Spanish Carlos III Health Institute (PI16/00991 and PI19/00744

Copper-containing mesoporous bioactive glass promotes angiogenesis in an in vivo zebrafish model

The osteogenic and angiogenic responses of organisms to the ionic products of degradation of bioactive glasses (BGs) are being intensively investigated. The promotion of angiogenesis by copper (Cu) has been known for more than three decades. This element can be incorporated to delivery carriers, such as BGs, and the materials used in biological assays. In this work, Cu-containing mesoporous bioactive glass (MBG) in the SiO2-CaO-P2O5 compositional system was prepared incorporating 5% mol Cu (MBG-5Cu) by replacement of the corresponding amount of Ca. The biological effects of the ionic products of MBG biodegradation were evaluated on a well-known endothelial cell line, the bovine aorta endothelial cells (BAEC), as well as in an in vivo zebrafish (Danio rerio) embryo assay. The results suggest that ionic products of both MBG (Cu free) and MBG-5Cu materials promote angiogenesis. In vitro cell cultures show that the ionic dissolution products of these materials are not toxic and promote BAEC viability and migration. In addition, the in vivo assay indicates that both exposition and microinjection of zebrafish embryos with Cu free MBG material increase vessel number and thickness of the subintestinal venous plexus (SIVP), whereas assays using MBG-5Cu enhance this effect.The authors gratefully acknowledge the financial support provided by the Andalusian Ministry of Economy, Science and Innovation (Proyectos Excelencia Grants no. P10-CTS-6681 and no. P12-CTS-1507) and Spanish Ministry of Economy and Competitivity (BIO2014-56092-R). LBRS acknowledges the CONACYT-Mexico Fellowship PhD Program

Sol&ndash;Gel Synthesis of Endodontic Cements: Post-Synthesis Treatment to Improve Setting Performance and Bioactivity

The sol&ndash;gel process is a wet chemical technique that allows very fine control of the composition, microstructure, and final textural properties of materials, and has great potential for the synthesis of endodontic cements with improved properties. In this work, the influence of different sol&ndash;gel synthesis variables on the preparation of endodontic cement based on calcium silicate with Ca/Si stoichiometry equal to 3 was studied. Starting from the most optimal hydraulic composition selected, a novel second post-synthesis treatment using ethanol was essayed. The effects of the tested variables were analyzed by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, nitrogen physisorption, and Gillmore needles to determine the setting time and simulated body fluid (SBF) immersion to measure the bioactive response in vitro. The results indicated that the sol&ndash;gel technique is effective in obtaining bioactive endodontic cements (BECs) with high content of the hydraulic compound tricalcium silicate (C3S) in its triclinic polymorph. The implementation of a novel post-synthesis treatment at room temperature using ethanol allows obtaining a final BEC product with a finer particle size and a higher CaCO3 content, which results in an improved material in terms of setting time and bioactive response

Constructo útil para terapia de regeneración de tejidos, procedimiento de obtención y aplicaciones

Constructo útil para terapia de regeneración de tejidos, procedimiento de obtención y aplicaciones. La presente invención consiste en un constructo, formado por un biomaterial compatible biológicamente, que sirve de soporte sobre el que se cultivan uno o más tipos de células vivas, de forma que se obtiene una estructura compleja tridimensional. El biomaterial soporte que se emplea para la elaboración del constructo de la invención, es del tipo sílice mesosestructurada (SBA-15) y/o bien se trata de un biomaterial compuesto formado por una matriz de sílice del tipo SBA-15 sobre el que se crecen nanopartículas de hidroxiapatito de calcio (HA). El constructo está particularmente indicado para su aplicación en las intervenciones reconstructivas de cirugía ortopédica y traumatología, en cirugía cervical y también en cirugía oral y maxilofacial, para su aplicación en terapias celulares destinadas a la regeneración tisular y a la curación de enfermedades del tejido esquelético (cartilaginoso y óseo).Peer reviewedConsejo Superior de Investigaciones Científicas (España), Universidad de MálagaA1 Solicitud de patentes con informe sobre el estado de la técnic

Hydroxyapatite synthesis on mesoporous silica: A high resolution elecron microscopy study | Sintesis de hidroxiapatita en silica mesoporosa: Un estudio por microscopia electronica de alta resolucion

The synthesis of hydroxyapatite on mesoporous silica SBA-15 material and the resulting composite, after a specific thermal treatment, has been followed and studied by electron microscopy. After the synthesis the samples were undergone a double thermal treatment: First the samples were hydrothermally treated from 353 y 393 K in a 10 K range interval during 24 hours; after filtering and drying the materials had a second treatment at 773 K in air during 10 h. The samples were studied using scanning, analytical and transmission electron microscopy. Also STEM and high resolution electron microscopy (HREM) techniques were used to follow the structural evolution at the nanoscale after each thermal treatment. The growth of hydroxiapatite along the tunnels of the mesoporous silica was observed after thermal treatment at 60 and 80 °C being increased with the hydrothermal treatment temperature.Se agradece y reconoce el apoyo económico de la DGAPA de la Universidad Nacional Autónoma de México a uno de los autores (DRA), para realizar una visita de trabajo a la Universidad de Sevilla. También al Ministerio Ministerio de Educación y Ciencia (Convenio MEC-CSIC I3); Proyecto Intramural Especial (PIE); 200660I122. Se tuvo también y se agradece,un apoyo parcial y limitado del proyecto PIFUT08-129 del ICYTDF.Peer Reviewe

Sol&ndash;Gel Technologies to Obtain Advanced Bioceramics for Dental Therapeutics

The aim of this work is to review the application of bioceramic materials in the context of current regenerative dentistry therapies, focusing on the latest advances in the synthesis of advanced materials using the sol&ndash;gel methodology. Chemical synthesis, processing and therapeutic possibilities are discussed in a structured way, according to the three main types of ceramic materials used in regenerative dentistry: bioactive glasses and glass ceramics, calcium phosphates and calcium silicates. The morphology and chemical composition of these bioceramics play a crucial role in their biological properties and effectiveness in dental therapeutics. The goal is to understand their chemical, surface, mechanical and biological properties better and develop strategies to control their pore structure, shape, size and compositions. Over the past decades, bioceramic materials have provided excellent results in a wide variety of clinical applications related to hard tissue repair and regeneration. Characteristics, such as their similarity to the chemical composition of the mineral phase of bones and teeth, as well as the possibilities offered by the advances in nanotechnology, are driving the development of new biomimetic materials that are required in regenerative dentistry. The sol&ndash;gel technique is a method for producing synthetic bioceramics with high purity and homogeneity at the molecular scale and to control the surfaces, interfaces and porosity at the nanometric scale. The intrinsic nanoporosity of materials produced by the sol&ndash;gel technique correlates with the high specific surface area, reactivity and bioactivity of advanced bioceramics