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Nanomaterials in biomedicine are materials designed at a scale of 1-100 nanometers that make it possible to diagnose, treat and prevent diseases using tools and knowledge of the human body at the molecular scale [...].
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Nanoestructuras , HumanosRESUMEN
Research in nanomaterials with applications in bone regeneration therapies has experienced a very significant advance with the development of bioactive mesoporous nanoparticles (MBNPs). These nanomaterials consist of small spherical particles that exhibit chemical properties and porous structures that stimulate bone tissue regeneration, since they have a composition similar to that of conventional sol-gel bioactive glasses and high specific surface area and porosity values. The rational design of mesoporosity and their ability to incorporate drugs make MBNPs an excellent tool for the treatment of bone defects, as well as the pathologies that cause them, such as osteoporosis, bone cancer, and infection, among others. Moreover, the small size of MBNPs allows them to penetrate inside the cells, provoking specific cellular responses that conventional bone grafts cannot perform. In this review, different aspects of MBNPs are comprehensively collected and discussed, including synthesis strategies, behavior as drug delivery systems, incorporation of therapeutic ions, formation of composites, specific cellular response and, finally, in vivo studies that have been performed to date.
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Nanopartículas , Nanoestructuras , Sistemas de Liberación de Medicamentos , Nanopartículas/química , Regeneración Ósea , Preparaciones Farmacéuticas , Huesos , Porosidad , Vidrio/químicaRESUMEN
Zinc-enriched mesoporous bioactive glasses (MBGs) are bioceramics with potential antibacterial and osteogenic properties. However, few assays have been performed to study these properties in animal models. In this study, MBGs enriched with up to 5% ZnO were synthesized, physicochemically characterized, and evaluated for their osteogenic activity both in vitro and in vivo. The ZnO MBGs showed excellent textural properties despite ZnO incorporation. However, the release of Zn2+ ions inhibited the mineralization process when immersed in simulated body fluid. In vitro assays showed significantly higher values of viability and expression of early markers of cell differentiation and angiogenesis in a ZnO-content-dependent manner. The next step was to study the osteogenic potential in a sheep bone defect model. Despite their excellent textural properties and cellular response in vitro, the ZnO MBGs were not able to integrate into the bone tissue, which can be explained in terms of inhibition of the mineralization process caused by Zn2+ ions. This work highlights the need to develop nanostructured materials for bone regeneration that can mineralize to interact with bone tissue and induce the processes of implant acceptance, cell colonization by osteogenic cells, and regeneration of lost bone tissue.
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Óxido de Zinc , Zinc , Ovinos , Animales , Zinc/farmacología , Zinc/química , Vidrio/química , Porosidad , Óxido de Zinc/farmacología , Modelos AnimalesRESUMEN
Mesoporous bioactive glass nanospheres (NanoMBGs) have high potential for clinical applications. However, the impact of these nanoparticles on the immune system needs to be addressed. In this study, the biocompatibility of SiO2-CaO NanoMBGs was evaluated on different mouse immune cells, including spleen cells subsets, bone marrow-derived dendritic cells (BMDCs), or cell lines like SR.D10 Th2 CD4+ lymphocytes and DC2.4 dendritic cells. Flow cytometry and confocal microscopy show that the nanoparticles were rapidly and efficiently taken up in vitro by T and B lymphocytes or by specialized antigen-presenting cells (APCs) like dendritic cells (DCs). Nanoparticles were not cytotoxic and had no effect on cell viability or proliferation under T-cell (anti-CD3) or B cell (LPS) stimuli. Besides, NanoMBGs did not affect the balance of spleen cell subsets, or the production of intracellular or secreted pro- and anti-inflammatory cytokines (TNF-α, IFN-γ, IL-2, IL-6, IL-10) by activated T, B, and dendritic cells (DC), as determined by flow cytometry and ELISA. T cell activation surface markers (CD25, CD69 and Induced Costimulator, ICOS) were not altered by NanoMBGs. Maturation of BMDCs or DC2.4 cells in vitro was not altered by NanoMBGs, as shown by expression of Major Histocompatibility Complex (MHC) and costimulatory molecules (CD40, CD80, CD86), or IL-6 secretion. The effect of wortmannin and chlorpromazine indicate a role for phosphoinositide 3-kinase (PI3K), actin and clathrin-dependent pathways in NanoMBG internalization. We thus demonstrate that these NanoMBGs are both non-toxic and non-inflammagenic for murine lymphoid cells and myeloid DCs despite their efficient intake by the cells.
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Compuestos de Calcio/química , Células Dendríticas/efectos de los fármacos , Ensayo de Materiales/métodos , Nanosferas/química , Óxidos/química , Dióxido de Silicio/química , Animales , Células de la Médula Ósea/citología , Células de la Médula Ósea/efectos de los fármacos , Células de la Médula Ósea/fisiología , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/inmunología , Células Cultivadas , Citocinas/metabolismo , Células Dendríticas/citología , Células Dendríticas/inmunología , Femenino , Técnicas Inmunológicas , Mediadores de Inflamación/metabolismo , Activación de Linfocitos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C57BL , Porosidad , Bazo/citologíaRESUMEN
An increase of bone diseases incidence has boosted the study of ceramic biomaterials as potential osteo-inductive scaffolds. In particular, mesoporous bioactive glasses have demonstrated to possess a broad application in the bone regeneration field, due their osteo-regenerative capability and their ability to release drugs from the mesoporous structure. These special features have been studied as an option to fight against bone infection, which is one of the most common problems regarding bone regeneration therapies. In this work, a mesoporous bioglass functionalized with polyamines and capped with adenosine triphosphate (ATP) as the molecular gate was developed for the controlled release of the antibiotic levofloxacin. Phosphate bonds of ATP were hydrolyzed in the presence of acid phosphatase (APase), the concentration of which is significantly increased in bone infection due to the activation of bone resorption processes. The solid was characterized and tested successfully against bacteria. The final gated solid induced bacterial death only in the presence of acid phosphatase. Additionally, it was demonstrated that the solid is not toxic against human cells. The double function of the prepared material as a drug delivery system and bone regeneration enhancer confirms the possible development of a new approach in the tissue engineering field, in which controlled release of therapeutic agents can be finely tuned and, at the same time, osteoinduction is favored.
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Antibacterianos/administración & dosificación , Sustitutos de Huesos/química , Cerámica/química , Preparaciones de Acción Retardada/química , Infecciones por Escherichia coli/prevención & control , Escherichia coli/efectos de los fármacos , Levofloxacino/administración & dosificación , Adenosina Trifosfato/química , Antibacterianos/farmacología , Línea Celular , Humanos , Levofloxacino/farmacología , Poliaminas/química , PorosidadRESUMEN
Diabetes mellitus (DM) induces bone deterioration, while mechanical stimulation promotes osteocyte-driven bone formation. We aimed to evaluate the interaction of acute exposure (24 h) to high glucose (HG) with both the pro-survival effect conferred to osteocytic MLO-Y4 cells and osteoblastic MC3T3-E1 cells by mechanical stimulation and the interaction of these cells with osteoclast precursor RAW264.7 cells. We found that 24 h of HG (25 mM) pre-exposure prevented both cell survival and ERK and ß-catenin nuclear translocation upon mechanical stimulation by fluid flow (FF) (10 min) in both MLO-Y4 and MC3T3-E1 cells. However, migration of RAW 264.7 cells was inhibited by MLO-Y4 cell-conditioned medium (CM), but not by MC3T3-E1 cell-CM, with HG or FF. This inhibitory effect was associated with consistent changes in VEGF, RANTES, MIP-1α, MIP-1ß MCP-1, and GM-CSF in MLO-Y4 cell-CM. RAW264.7 proliferation was inhibited by MLO-Y4 CM under static or HG conditions, but it increased by FF-CM with or without HG. In addition, both FF and HG abrogated the capacity of RAW 264.7 cells to differentiate into osteoclasts, but in a different manner. Thus, HG-CM in static condition allowed formation of osteoclast-like cells, which were unable to resorb hydroxyapatite. In contrast, FF-CM prevented osteoclastogenesis even in HG condition. Moreover, HG did not affect basal RANKL or IL-6 secretion or their inhibition induced by FF in MLO-Y4 cells. In conclusion, this in vitro study demonstrates that HG exerts disparate effects on osteocyte mechanotransduction, and provides a novel mechanism by which DM disturbs skeletal metabolism through altered osteocyte-osteoclast communication.
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Diferenciación Celular/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Glucosa/farmacología , Mecanotransducción Celular/efectos de los fármacos , Osteoclastos/efectos de los fármacos , Osteocitos/efectos de los fármacos , Osteogénesis/efectos de los fármacos , Células Madre/efectos de los fármacos , Células 3T3 , Animales , Comunicación Celular/efectos de los fármacos , Citocinas/metabolismo , Ratones , Osteoclastos/metabolismo , Osteocitos/metabolismo , Estimulación Física , Células RAW 264.7 , Células Madre/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Magnetically triggered drug delivery nanodevices have attracted great attention in nanomedicine, as they can feature as smart carriers releasing their payload at clinician's will. The key principle of these devices is based on the properties of magnetic cores to generate thermal energy in the presence of an alternating magnetic field. Then, the temperature increase triggers the drug release. Despite this potential, the rapid heat dissipation in living tissues is a serious hindrance for their clinical application. It is hypothesized that magnetic cores could act as hot spots, this is, produce enough heat to trigger the release without the necessity to increase the global temperature. Herein, a nanocarrier has been designed to respond when the temperature reaches 43 °C. This material has been able to release its payload under an alternating magnetic field without the need of increasing the global temperature of the environment, proving the efficacy of the hot spot mechanism in magnetic-responsive drug delivery devices.
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Sistemas de Liberación de Medicamentos/instrumentación , Fenómenos Magnéticos , Acrilamidas/química , Resinas Acrílicas/química , Preparaciones de Acción Retardada , Fluoresceína/química , Nanopartículas/química , Dióxido de Silicio/químicaRESUMEN
The aim of this study was to propose and validate a new unified method for testing dissolution rates of bioactive glasses and their variants, and the formation of calcium phosphate layer formation on their surface, which is an indicator of bioactivity. At present, comparison in the literature is difficult as many groups use different testing protocols. An ISO standard covers the use of simulated body fluid on standard shape materials but it does not take into account that bioactive glasses can have very different specific surface areas, as for glass powders. Validation of the proposed modified test was through round robin testing and comparison to the ISO standard where appropriate. The proposed test uses fixed mass per solution volume ratio and agitated solution. The round robin study showed differences in hydroxyapatite nucleation on glasses of different composition and between glasses of the same composition but different particle size. The results were reproducible between research facilities. Researchers should use this method when testing new glasses, or their variants, to enable comparison between the literature in the future.
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Apatitas/química , Materiales Biomiméticos/química , Materiales Biomiméticos/normas , Líquidos Corporales/química , Cerámica/química , Vidrio/química , Ensayo de Materiales/normas , Apatitas/normas , Cerámica/análisis , Cerámica/normas , Vidrio/análisis , Vidrio/normas , Internacionalidad , Ensayo de Materiales/métodos , Tamaño de la Partícula , Estándares de Referencia , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
A new approach towards the design of "gated scaffolds" based on the combination of capped mesoporous silica nanoparticles (MSNs) with porous biomaterials is reported. Using this approach, a 3D gelatin-based scaffold able to selectively deliver cargo in the presence of an APase enzyme is prepared and tested. This new design opens up the possibility of developing new smart biomaterials with advanced drug-delivery features.
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Materiales Biocompatibles/química , Portadores de Fármacos , Sistemas de Liberación de Medicamentos , Imagenología Tridimensional/métodos , Adenosina Trifosfato/química , Aniones , Geles/química , Enlace de Hidrógeno , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Nanopartículas/química , Nanotecnología/métodos , Porosidad , Regeneración , Dióxido de Silicio/química , Ingeniería de Tejidos/métodos , Difracción de Rayos XRESUMEN
Bioactive mesoporous glass nanospheres (nanoMBGs) charged with antiosteoporotic drugs have great potential for the treatment of osteoporosis and fracture prevention. In this scenario, cells of the immune system are essential both in the development of disease and in their potential to stimulate therapeutic effects. In the present work, we hypothesize that nanoMBGs loaded with ipriflavone can exert a positive osteoimmune effect. With this objective, we assessed the effects of non-loaded and ipriflavone-loaded nanoparticles (nanoMBGs and nanoMBG-IPs, respectively) on CD4+ Th2 lymphocytes because this kind of cell is implicated in the inhibition of osseous loss by reducing the RANKL/OPG relationship through the secretion of cytokines. The results indicate that nanoMBGs enter efficiently in CD4+ Th2 lymphocytes, mainly through phagocytosis and clathrin-dependent mechanisms, without affecting the function of these T cells or inducing inflammatory mediators or oxidative stress, thus maintaining the reparative Th2 phenotype. Furthermore, the incorporation of the anti-osteoporotic drug ipriflavone reduces the potential unwanted inflammatory response by decreasing the presence of ROS and stimulating intracellular anti-inflammatory cytokine release like IL-4. These results evidenced that nanoMBG loaded with ipriflavone exerts a positive osteoimmune effect.
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OBJECTIVE: Four modifications were introduced in the Lifetime Vaccination Schedule of the Interterritorial Council of the National Health System (CISNS) in 2023.The aim of this study was to estimate the cost of vaccinating a healthy person and people with certain risk conditions throughout life in Spain and to compare with a previous estimation from 2019. METHODS: A descriptive study of the cost of administering the vaccines included in the Lifetime Vaccination Schedule for the year 2023 and in the schedule for risk groups was carried out. RESULTS: The estimated cost to immunize a healthy person throughout life in 2023 is 1,541.56 for a woman and 1,498.18 for a men, which corresponds to an increase of 125% compared to the cost in 2019. The risk conditions with the highest cost are asplenia and complement deficiency and primary immunodeficiencies, with a cost of 3,159.82 euros and 2,566 euros respectively on average. The cost of vaccinating the whole healthy population in Spain in a year is around 565M. Moreover, the cost of vaccinating the new-borns cohort of 2023 was estimated at 500M. CONCLUSIONS: Despite the cost increase in 2023, immunization is still a very cheap intervention, considering the economic impact of immunopreventable diseases in the society. The relative low cost of immunization throughout life makes this health intervention useful and worthwhile.
OBJECTIVE: En el calendario de vacunación a lo largo de toda la vida del Consejo Interterritorial del Sistema Nacional de Salud (CISNS) se introdujeron cuatro modificaciones importantes en 2023. El objetivo de este estudio fue estimar el coste de la vacunación a lo largo de toda la vida a una persona sana y a ciertos grupos de riesgo tomando como referencia el calendario de 2023 y compararlo con una estimación previa de 2019. METHODS: Se realizo un estudio descriptivo del coste de administrar las vacunas incluidas en el calendario de vacunación a lo largo de toda la vida para el año 2023 y en el calendario para grupos de riesgo. RESULTS: El coste estimado de vacunar a una persona sana a lo largo de toda la vida en 2023 es de 1.541,56 euros en mujeres y 1.498,18 euros en hombres, lo que supondría un incremento del 125% con respecto al coste en 2019. Las condiciones de riesgo con el coste más alto son asplenia además de déficit del complemento e inmunodeficiencias primarias, suponiendo 3.159.82 euros y 2.566 euros, respectivamente, de media. Vacunar a toda la población sana en España en un año costaría unos 565 millones de euros y vacunar a la cohorte de recién nacidos de 2023 a lo largo de toda la vida unos 500 millones de euros. CONCLUSIONS: A pesar del incremento en el coste en 2023, considerando el impacto económico de las enfermedades prevenibles por vacunación en la sociedad, la vacunación sigue siendo una intervención barata que aporta múltiples beneficios.
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Estado de Salud , Vacunación , Masculino , Femenino , Humanos , España , Esquemas de InmunizaciónRESUMEN
Background: Coriander, like other leafy green vegetables, is available all year round and is commonly consumed raw in Mexico as in other countries in the preparation of street or homemade food. Bacillus cereus (B. cereus) is a microorganism that can reach coriander because it is usually found in the soil and in some regions the vegetables are irrigated with polluted water. Therefore, the aim of this study was to determinate the presence of B. cereus in coriander used for human consumption in southwestern Mexico and determine the toxigenic profile, biofilm production, genes associated with the production of biofilms, sporulation rates, enzymatic profile, psychotropic properties, and genetic diversity of B. cereus. Methods: Fresh coriander samples were collected from several vegetable retailers in different markets, microbiological analysis was performed. Molecular identification, genes related to the production of biofilm, and toxin gene profiling of B. cereus isolates were determined by PCR. The biofilm formation was measured by performing a crystal violet assay. The genetic diversity of B. cereus strains was determined by PCR of repetitive elements using oligonucleotide (GTG) 5. Results: We found a frequency of B. cereus in vegetables was 20% (13/65). In this study, no strains with genes for the HBL toxin were found. In the case of genes related to biofilms, the frequency was low for sipW [5.8%, (1/17)] and tasA [11.7%, (2/17)]. B. cereus strains produce a low amount of biofilm with sporulation rates around 80%. As for genetic diversity, we observed that strains isolated from the same market, but different vegetable retailers are grouped into clusters. In the coriander marketed in southwestern Mexico, were found B. cereus strains with genes associated with the production of diarrheal toxins. Together, these results show actual information about the state of art of B. cereus strains circulating in the southwestern of Mexico.
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Coriandrum , Enterotoxinas , Humanos , Enterotoxinas/análisis , Microbiología de Alimentos , Bacillus cereus/genética , México , Verduras/microbiología , Variación Genética/genéticaRESUMEN
Fibroblast growth factors (FGFs) are polypeptides that control the proliferation and differentiation of various cell types including osteoblasts. FGFs are also strong inducers of angiogenesis, necessary to obtain oxygen and nutrients during tissue repair. With the aim to incorporate these desirable FGF biological properties into bioceramics for bone repair, silicon substituted hydroxyapatites (Si-HA) were used as materials to immobilize bioactive FGF-1 and FGF-2. Thus, the binding of these growth factors to powdered Si-HA and Si-HA scaffolds was carried out efficiently in the present study and both FGFs maintained its biological activity on osteoblasts after its immobilization. The improvement of cell adhesion and proliferation onto Si-HA scaffolds suggests the potential utility of these FGF/scaffolds for bone tissue engineering.
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Huesos/metabolismo , Durapatita/química , Factor 1 de Crecimiento de Fibroblastos/metabolismo , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Silicio/química , Ingeniería de Tejidos/métodos , Apatitas/química , Adhesión Celular , Proliferación Celular , Citometría de Flujo/métodos , Humanos , Microscopía Confocal/métodos , Neovascularización Patológica , Osteoblastos/citología , Oxígeno/química , Polvos , Especies Reactivas de OxígenoRESUMEN
In order to increase the bone forming ability of MBG-PCL composite scaffold, microporosity was created in the struts of 3D-printed MBG-PCL scaffolds for the manufacturing of a construct with a multiscale porosity consisting of meso- micro- and macropores. 3D-printing imparted macroporosity while the microporosity was created by porogen removal from the struts, and the MBG particles were responsible for the mesoporosity. The scaffolds were 3D-printed using a mixture of PCL, MBG and phosphate buffered saline (PBS) particles, subsequently leached out. Microporous-PCL (pPCL) as a negative control, microporous MBG-PCL (pMBG-PCL) and non-microporous-MBG-PCL (MBG-PCL) were investigated. Scanning electron microscopy, mercury intrusion porosimetry and micro-computed tomography demonstrated that the PBS removal resulted in the formation of micropores inside the struts with porosity of around 30% for both pPCL and pMBG-PCL, with both constructs displaying an overall porosity of 8090%. In contrast, the MBG-PCL group had a microporosity of 6% and an overall porosity of 70%. Early mineralisation was found in the pMBG-PCL post-leaching out and this resulted in the formation a more homogeneous calcium phosphate layer when using a biomimetic mineralisation assay. Mechanical properties ranged from 5 to 25 MPa for microporous and non-microporous specimens, hence microporosity was the determining factor affecting compressive properties. MC3T3-E1 metabolic activity was increased in the pMBG-PCL along with an increased production of RUNX2. Therefore, the microporosity within a 3D-printed bioceramic composite construct may result in additional physical and biological benefits.
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Regeneración Ósea , Andamios del Tejido , Cerámica , Osteogénesis , Porosidad , Impresión Tridimensional , Ingeniería de Tejidos , Microtomografía por Rayos XRESUMEN
Angiogenic biomaterials are designed to promote vascularization and tissue regeneration. Nanoparticles of bioactive materials loaded with drugs represent an interesting strategy to stimulate osteogenesis and angiogenesis and to inhibit bone resorption. In this work, porcine endothelial progenitor cells (EPCs), essential for blood vessel formation, were isolated and characterized to evaluate the in vitro effects of unloaded (NanoMBGs) and ipriflavone-loaded nanospheres (NanoMBG-IPs), which were designed to prevent osteoporosis. The expression of vascular endothelial growth factor receptor 2 (VEGFR2) was studied in EPCs under different culture conditions: (a) treatment with NanoMBGs or NanoMBG-IPs, (b) culture with media from basal, M1, and M2 macrophages previously treated with NanoMBGs or NanoMBG-IPs, (c) coculture with macrophages in the presence of NanoMBGs or NanoMBG-IPs, and (d) coculture with M2d angiogenic macrophages. The endocytic mechanisms for nanosphere incorporation by EPCs were identified using six different endocytosis inhibitors. The results evidence the great potential of these nanomaterials to enhance VEGFR2 expression and angiogenesis, after intracellular incorporation by EPCs through clathrin-dependent endocytosis, phagocytosis, and caveolae-mediated uptake. The treatment of EPCs with basal, M1, and M2 macrophage culture media and EPC/macrophage coculture studies also confirmed the angiogenic effect of these nanospheres on EPCs, even in the presence of phagocytic cells.
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Due to their specific mesoporous structure and large surface area, mesoporous bioactive glasses (MBGs) possess both drug-delivery ability and effective ionic release to promote bone regeneration by stimulating osteogenesis and angiogenesis. Macrophages secrete mediators that can affect both processes, depending on their phenotype. In this work, the action of ion release from MBG-75S, with a molar composition of 75SiO2-20CaO-5P2O5, on osteogenesis and angiogenesis and the modulatory role of macrophages have been assessed in vitro with MC3T3-E1 pre-osteoblasts and endothelial progenitor cells (EPCs) in monoculture and in coculture with RAW 264.7 macrophages. Ca2+, phosphorous, and silicon ions released from MBG-75S were measured in the culture medium during both differentiation processes. Alkaline phosphatase activity and matrix mineralization were quantified as the key markers of osteogenic differentiation in MC3T3-E1 cells. The expression of CD31, CD34, VEGFR2, eNOS, and vWF was evaluated to characterize the EPC differentiation into mature endothelial cells. Other cellular parameters analyzed included the cell size and complexity, intracellular calcium, and intracellular content of the reactive oxygen species. The results obtained indicate that the ions released by MBG-75S promote osteogenesis and angiogenesis in vitro, evidencing a macrophage inhibitory role in these processes and demonstrating the high potential of MBG-75S for the preparation of implants for bone regeneration.
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Mesoporous bioactive glasses (MBGs) associated with an anti-osteoporotic drug (ipriflavone) have been prepared. With this aim, MBGs were functionalised with different organic groups by following a post-grafting method, thus retaining the mesoporous network of the bioactive substrates. Drug-delivery tests were carried out by using ipriflavone as a hydrophobic model drug. Our results revealed that by means of the proper functionalisation, most of the drug is retained in the mesoporous network. By tailoring the hydrophobicity of the surface with functional groups, the drug-material link can be tuned, thereby ensuring the long-term delivery of ipriflavone. In vitro bioactive tests demonstrate that these systems exhibit the same excellent behaviour of non-functionalised MBGs. The possibility to add a bone resorption inhibitor such as ipriflavone to highly bioactive materials confirms functionalised MBGs as very promising bone-tissue regeneration systems.
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Materiales Biocompatibles/química , Cerámica/química , Sistemas de Liberación de Medicamentos/métodos , Vidrio/química , Isoflavonas/química , Regeneración Ósea , Interacciones Hidrofóbicas e Hidrofílicas , Isoflavonas/farmacologíaRESUMEN
Surface modification of orthopedic and dental implants has been demonstrated to be an effective strategy to accelerate bone healing at early implantation times. Among the different alternatives, coating implants with a layer of hydroxyapatite (HAp) is one of the most used techniques, due to its excellent biocompatibility and osteoconductive behavior. The composition and crystalline structure of HAp allow for numerous ionic substitutions that provide added value, such as antibiotic properties or osteoinduction. In this article, we will review and critically analyze the most important advances in the field of substituted hydroxyapatite coatings. In recent years substituted HAp coatings have been deposited not only on orthopedic prostheses and dental implants, but also on macroporous scaffolds, thus expanding their applications towards bone regeneration therapies. Besides, the capability of substituted HAps to immobilize proteins and growth factors by non-covalent interactions has opened new possibilities for preparing hybrid coatings that foster bone healing processes. Finally, the most important in vivo outcomes will be discussed to understand the prospects of substituted HAp coatings from a clinical point of view.
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Sustitutos de Huesos/química , Materiales Biocompatibles Revestidos/química , Implantes Dentales , Durapatita/química , Animales , Regeneración Ósea/efectos de los fármacos , Humanos , Ensayo de MaterialesRESUMEN
Three-dimensional Mesoporous bioactive glasses (MBGs) scaffolds has been widely considered for bone regeneration purposes and additive manufacturing enables the fabrication of highly bioactive patient-specific constructs for bone defects. Commonly, this process is performed with the addition of polymeric binders that facilitate the printability of scaffolds. However, these additives cover the MBG particles resulting in the reduction of their osteogenic potential. The present work investigates a simple yet effective phosphate-buffered saline immersion method for achieving polyvinyl alcohol binder removal while enables the maintenance of the mesoporous structure of MBG 3D-printed scaffolds. This resulted in significantly modifying the surface of the scaffold via the spontaneous formation of a biomimetic mineralized layer which positively affected the physical and biological properties of the scaffold. The extensive surface remodeling induced by the deposition of the apatite-like layer lead to a 3-fold increase in surface area, a 5-fold increase in the roughness, and 4-fold increase in the hardness of the PBS-immersed scaffolds when compared to the as-printed counterpart. The biomimetic mineralization also occurred throughout the bulk of the scaffold connecting the MBGs particles and was responsible for the maintenance of structural integrity. In vitro assays using MC3T3-E1 pre-osteoblast like cells demonstrated a significant upregulation of osteogenic-related genes for the scaffolds previously immersed in PBS when compared to the as-printed PVA-containing scaffolds. Although the pre-immersion scaffolds performed equally towards osteogenic cell differentiation, our data suggest that a short immersion in PBS of MBG scaffolds is beneficial for the osteogenic properties and might accelerate bone formation after implantation.
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Materiales Biomiméticos/química , Calcificación Fisiológica , Cerámica/química , Osteoblastos/metabolismo , Osteogénesis , Impresión Tridimensional , Andamios del Tejido/química , Animales , Línea Celular , Ratones , Osteoblastos/citología , PorosidadRESUMEN
The incorporation and effects of hollow mesoporous nanospheres in the system SiO2-CaO (nanoMBGs) containing ipriflavone (IP), a synthetic isoflavone that prevents osteoporosis, were evaluated. Due to their superior porosity and capability to host drugs, these nanoparticles are designed as a potential alternative to conventional bioactive glasses for the treatment of periodontal defects. To identify the endocytic mechanisms by which these nanospheres are incorporated within the MC3T3-E1 cells, five inhibitors (cytochalasin B, cytochalasin D, chlorpromazine, genistein and wortmannin) were used before the addition of these nanoparticles labeled with fluorescein isothiocyanate (FITC-nanoMBGs). The results indicate that nanoMBGs enter the pre-osteoblasts mainly through clathrin-dependent mechanisms and in a lower proportion by macropinocytosis. The present study evidences the active incorporation of nanoMBG-IPs by MC3T3-E1 osteoprogenitor cells that stimulate their differentiation into mature osteoblast phenotype with increased alkaline phosphatase activity. The final aim of this study is to demonstrate the biocompatibility and osteogenic behavior of IP-loaded bioactive nanoparticles to be used for periodontal augmentation purposes and to shed light on internalization mechanisms that determine the incorporation of these nanoparticles into the cells.