Estudio de biocompatibilidad de matrices poliméricas combinadas, responsivas al pH, con aplicación en Ingeniería de Tejido Óseo / Biocompatibility study of combined pH-responsive polymeric matrices with application in Bone Tissue Engineering

El presente trabajo muestra la obtención de un material a partir de un polímero sintético (TerP) y otro natural, mediante entrecruzamiento físico y su caracterización fisicoquímica y biológica, con el fin de emplearlos para regeneración de tejido óseo. Las membranas fueron obtenidas por la técnica de evaporación del solvente y caracterizadas por espectroscopia FTIR, ensayos de hinchamiento, medidas de ángulo de contacto y microscopia electrónica de barrido (SEM). Se encontró que la compatibilidad entre los polímeros que la constituyen es estable a pH fisiológico y que, al incorporar mayor cantidad del TerP a la matriz, esta se vuelve más hidrofóbica y porosa. Además, teniendo en cuenta la aplicación prevista para dichos materiales, se realizaron estudios de biocompatibilidad y citotoxicidad con células progenitoras de médula ósea (CPMO) y células RAW264.7, respectivamente. Se evaluó la proliferación celular, la producción y liberación de óxido nítrico (NO) al medio de cultivo durante 24 y 48 horas y la expresión de citoquinas proinflamatorias IL-1ß y TNF-α de las células crecidas sobre los biomateriales variando la cantidad del polímero sintético. Se encontró mayor proliferación celular y menor producción de NO sobre las matrices que contienen menos proporción del TerP, además de poseer una mejor biocompatibilidad. Los resultados de este estudio muestran que el terpolímero obtenido y su combinación con un polímero natural es una estrategia muy interesante para obtener un biomaterial con posibles aplicaciones en medicina regenerativa y que podría extenderse a otros sistemas estructuralmente relacionados. (AU)

In the present work, the preparation of a biomaterial from a synthetic terpolymer (TerP) and a natural polymer, physically crosslinked, is shown. In order to evaluate the new material for bone tissue regeneration, physicochemical and biological characterizations were performed. The membranes were obtained by solvent casting and characterized using FTIR spectroscopy, swelling tests, contact angle measurements, and scanning electron microscopy (SEM). It was found that the compatibility between the polymers is stable at physiological pH and the incorporation of a higher amount of TerP into the matrix increases hydrophobicity and porosity.Furthermore, considering the intended application of these materials, studies of biocompatibility and cytotoxicity were conducted with Bone Marrow Progenitor Cells (BMPCs) and RAW264.7 cells, respectively. Cell proliferation, NO production and release into the culture medium for 24 and 48 hours, and proinflammatory cytokine expression of IL-1ß and TNF-α from cells grown on the biomaterials while varying the amount of the synthetic polymer were evaluated. Greater cell proliferation and lower NO production were found on matrices containing a lower proportion of TerP, in addition to better biocompatibility. The results of this study demonstrate that the obtained terpolymer and its combination with a natural polymer is a highly interesting strategy for biomaterial preparation with potential applications in regenerative medicine. This approach could be extended to other structurally related systems. (AU)

Effects of Platycodonis Radix-Curcumae Rhizoma on oral nanoparticle uptake and in vitro inhibition against breast cancer metastasis / 中国中药杂志

This study combined the herbal pair Platycodonis Radix-Curcumae Rhizoma(PR-CR) possessing an inhibitory effect on tumor cell proliferation and metastasis with the active component of traditional Chinese medicine(TCM) silibinin-loaded nanoparticles(NPs) with a regulatory effect on tumor microenvironment based on the joint effect on tumor cells and tumor microenvironment to inhi-bit cell metastasis. The effects of PR-CR on the cellular uptake of NPs and in vitro inhibition against breast cancer proliferation and metastasis were investigated to provide an experimental basis for improving nanoparticle absorption and enhancing therapeutic effects. Silibinin-loaded lipid-polymer nanoparticles(LPNs) were prepared by the nanoprecipitation method and characterized by transmission electron microscopy. The NPs were spherical or quasi-spherical in shape with obvious core-shell structure. The mean particle size was 107.4 nm, Zeta potential was-27.53 mV. The cellular uptake assay was performed by in vitro Caco-2/E12 coculture cell model and confocal laser scanning microscopy(CLSM), and the results indicated that PR-CR could promote the uptake of NPs. Further, in situ intestinal absorption assay by the CLSM vertical scanning approach showed that PR-CR could promote the absorption of NPs in the enterocytes of mice. The inhibitory effect of NPs on the proliferation and migration of 4T1 cells was analyzed using 4T1 breast cancer cells and co-cultured 4T1/WML2 cells, respectively. The results of the CCK8 assay showed that PR-CR-containing NPs could enhance the inhibition against the proliferation of 4T1 breast cancer cells. The wound healing assay indicated that PR-CR-containing NPs enhanced the inhibition against the migration of 4T1 breast cancer cells. This study enriches the research on oral absorption of TCM NPs and also provides a new idea for utilizing the advantages of TCM to inhibit breast cancer metastasis.

Effect of polymer nanoparticles on atherosclerotic lesions and the associated mechanisms: a review / 生物工程学报

Polymer nanoparticles generally refer to hydrophobic polymers-based nanoparticles, which have been extensively studied in the nanomedicine field due to their good biocompatibility, efficient long-circulation characteristics, and superior metabolic discharge patterns over other nanoparticles. Existing studies have proved that polymer nanoparticles possess unique advantages in the diagnosis and treatment of cardiovascular diseases, and have been transformed from basic researches to clinical applications, especially in the diagnosis and treatment of atherosclerosis (AS). However, the inflammatory reaction induced by polymer nanoparticles would induce the formation of foam cells and autophagy of macrophages. In addition, the variations in the mechanical microenvironment of cardiovascular diseases may cause the enrichment of polymer nanoparticles. These could possibly promote the occurrence and development of AS. Herein, this review summarized the recent application of polymer nanoparticles in the diagnosis and treatment of AS, as well as the relationship between polymer nanoparticles and AS and the associated mechanism, with the aim to facilitate the development of novel nanodrugs for the treatment of AS.

Research Advances in Medical Materials and Products for Soft Tissue Repairs / 中国医疗器械杂志

Soft tissue is an indispensable tissue in human body. It plays an important role in protecting the body from external physical, chemical or biological factors. Mild soft tissue injuries can self-heal, while severe soft tissue injuries may require related treatment. Natural polymers (such as chitosan, hyaluronic acid, and collagen) and synthetic polymers (such as polyethylene glycol and polylactic acid) exhibit good biocompatibility, biodegradability and low toxicity. It can be used for soft tissue repairs for antibacterial, hemostatic and wound healing purposes. Their related properties can be enhanced through modification or preparation of composite materials. Commonly used soft tissue repairs include wound dressings, biological patches, medical tissue adhesives, and tissue engineering scaffolds. This study introduces the properties, mechanisms of action and applications of various soft tissue repair medical materials, including chitosan, hyaluronic acid, collagen, polyethylene glycol and polylactic acid, and provides an outlook on the application prospects of soft tissue repair medical materials and products.

The relationships among Flory-Huggins specific interaction parameters, maximum amorphous capacity, and solid-state interactions of spray dried amorphous drug dispersions with conventional and novel pharmaceutical polymers / Las relaciones entre los parámetros de interacción específicos de Flry-Huggins, la capacidad amorfa máxima y las interacciones en estado sólido de las dispersiones de fármacos amorfos secados por aspersión con polímeros farmacéuticos convencionales y nuevos

This study evaluated the specific interactions between drug and polymers in amorphous spray dried dispersions (SDDs). Four Biopharmaceutics Classification System (BCS) II class drugs were evaluated. Binary and ternary SDDs were manufactured with conventional polymers and arabinogalactan. Specific interaction parameters between drug and polymer were determined using theoretical calculations and DSC data. Analytical methods were used to evaluate solid and solution state interactions. Maximum amorphous content for each formulation was calculated using DSC. Flory-Huggins Specific Interaction Parameters were calculated. Negative specific parameters were associated with solid-state interactions and improved capacity of drug in the amorphous state. Ternary SDDs containing drug, polymer, and arabinogalactan displayed similar hydrogen bonding as was observed with binary SDDs. Solution-state interactions observed in binary systems may be used in tertiary systems to improve the amorphous drug capacity and improved dissolution compared to the binary. The resultant tertiary systems are an improvement over binary drug polymer systems.

Este estudio evaluó las interacciones específicas entre el fármaco y los polímeros en dispersiones amorfas secadas por pulverización (SDD). Se evaluaron cuatro fármacos de clase II del Sistema de Clasificación Biofarmacéutica (BCS). Los SDD binarios y ternarios se fabricaron con polímeros convencionales y arabinogalactano. Los parámetros de interacción específicos entre el fármaco y el polímero se determinaron utilizando cálculos teóricos y datos de DSC. Se utilizaron métodos analíticos para evaluar las interacciones del estado sólido y de la solución. El contenido amorfo máximo para cada formulación se calculó usando DSC. Se calcularon los parámetros de interacción específicos de Flory-Huggins. Los parámetros específicos negativos se asociaron con interacciones en estado sólido y una capacidad mejorada del fármaco en el estado amorfo. Los SDD ternarios que contienen fármaco, polímero y arabinogalactano mostraron enlaces de hidrógeno similares a los observados con los SDD binarios. Las interacciones de estado de solución observadas en sistemas binarios pueden usarse en sistemas terciarios para mejorar la capacidad del fármaco amorfo y mejorar la disolución en comparación con el binario. Los sistemas terciarios resultantes son una mejora con respecto a los sistemas de polímeros de fármacos binarios.

Modification of polyetheretherketone (PEEK) physical features to improve osteointegration / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Polyetheretherketone (PEEK) has been widely applied in orthopedics because of its excellent mechanical properties, radiolucency, and biocompatibility. However, the bioinertness and poor osteointegration of PEEK have greatly limited its further application. Growing evidence proves that physical factors of implants, including their architecture, surface morphology, stiffness, and mechanical stimulation, matter as much as the composition of their surface chemistry. This review focuses on the multiple strategies for the physical modification of PEEK implants through adjusting their architecture, surface morphology, and stiffness. Many research findings show that transforming the architecture and incorporating reinforcing fillers into PEEK can affect both its mechanical strength and cellular responses. Modified PEEK surfaces at the macro scale and micro/nano scale have positive effects on cell-substrate interactions. More investigations are necessary to reach consensus on the optimal design of PEEK implants and to explore the efficiency of various functional implant surfaces. Soft-tissue integration has been ignored, though evidence shows that physical modifications also improve the adhesion of soft tissue. In the future, ideal PEEK implants should have a desirable topological structure with better surface hydrophilicity and optimum surface chemistry.

Late correction of orbital deformities using customized 3D implant / Corrección tardía de deformidades de órbita usando implantes personalizados 3D

SUMMARY: Late orbital reconstruction is a complex and challenge for surgeons. The aim of this article is to present complex orbital reconstruction using patient specific implant (PSI) strategy and polyetheretherketone (PEEK). A literature review and a cases series of sequelae after complex orbital trauma are presented; cases with great middle third deformities showing defect in the maxilla, nasal area, body of the zygoma and zygomatic arch were included; in both cases the sequelae was for more than 10 years. Virtual planning and PEEK implants were manufacture using a puzzle (two or three parts) by 3D print or injection. Patients were treated and their surgeries carried out without complications, using a minimal surgical approach. No infections were observed, and after 12 months follow-up they were stable showing normal function. PSI based-PEEK for orbital reconstruction are safe, efficient, effective and to obtain orbital morphology with low complications.

RESUMEN: La reconstrucción tardía de la órbita es un desafío complejo para cirujanos. El objetivo de este artículo fue presentar la reconstrucción orbitaria compleja utilizando implante paciente específico (PSI) y polietereterketona (PEEK). Son presentados una revisión de literatura y una serie de casos con secuelas posteriores a un trauma orbitario complejo; además, son presentados casos con gran deformidad del tercio medio del rostro mostrando defectos en maxila, área nasal, cuerpo del hueso cigomático y arco cigomático; ambos casos de secuela fueron por más de 10 años. Planificación virtual e implantes en PEEK fueron creados usando una estrategia de puzzle (dos o tres partes) por inyección o impresión 3D. Los pacientes fueron tratados y sus cirugías realizadas sin complicaciones usando accesos quirúrgicos reducidos. No se observaron infecciones y después de 12 meses de seguimiento permanecieron estables mostrando función normal. Los PSI para reconstrucción orbitaria son seguros, eficientes, efectivos y recuperan morfología de órbita con bajas complicaciones.

Effect of sulfonated block copolymer on the equilibrium and thermal properties of sulfonated fluoroblock copolymer blend membrane / Efecto del copolímero en bloque sulfonado sobre las propiedades térmicas y de equilibrio de una membrana sulfonada mezclada con un fluoropolímero en bloque

Polymeric membrane technologies demand the synthesis of new polymers to enhance their equilibrium, thermal, and transport properties. Therefore, the focus of this investigation was the evaluation of the equilibrium and thermal properties of a sulfonated fluoroblock copolymer blend membrane composed of sulfonated poly(styre-ne-isobutylene-styrene) (SIBS SO3H) and a novel sulfonated fluoroblock copolymer composed of poly(4-fluo-rostyrene) (P4FS), poly(styrene) (PS) and poly(isobutylene) (PIB). The fluoroblock copolymer was synthesized using Atom Transfer Radical Polymerization (ATRP) and cationic polymerization. First, the molecular weight and the thermal stability of the block copolymer were determined using Gel Permeation Chromatography (GPC) and Thermogravimetric Analysis (TGA). Second, the chemical composition was monitored utilizing Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The molecular weight of P4FS-b-PS was Mn ~ 36,100; this value increased 8% after the cationic polymerization. The equilibrium properties of the membrane were evaluated using the water uptake and Ion-Exchange Capacity. The degradation behavior and the thermal transitions were determined using TGA and Differential Scanning Calorimetry (DSC), respectively. This newly membrane exhibited water uptake higher than 608% related to the improvement of 36% in the ion-exchange capacity and the increment of 25.31% and 25.24% in the energy required to produce the thermal transitions induced by the addition of the sulfonated fluoroblock copolymer.

La tecnología de membranas poliméricas requiere de la síntesis de nuevos polímeros que mejoren sus propiedades de equilibrio, térmicas y de transporte. Esta investigación tuvo como objetivo determinar las pro-piedades de equilibrio y térmicas de una membrana compuesta de poli(estireno-isobutileno-estireno) sulfonado (SIBS SO3H) y un fluoropolímero en bloque sulfonado compuesto de poli(4-fluorostireno) (P4FS), poli(estireno) (PS) y poli(isobutileno) (PIB). El fluoropolímero en bloque se sintetizó utilizando la técnica de polimerización radical por transferencia atómica (ATRP por sus siglas en inglés) y polimerización catiónica. El peso molecular y la estabilidad térmica del fluoropolímero en bloque fueron determinadas por medio de Cromatografía de Permeación en Gel (GPC) y un análisis termogravimétrico (TGA). La composición química se monitorizó utilizando espectroscopía infrarroja por transformada de Fourier (FTIR) y espectroscopía de Resonancia Magnética Nuclear (RMN). El peso molecular de P4FS-b-PS fue Mn ~ 36,100; este valor aumentó un 8% después de la polimerización catiónica. Las propiedades de equilibrio de la membrana fueron evaluadas por medio de la absorción de agua y la capacidad de intercambio iónico. El comportamiento de degradación y las transiciones térmicas se determinaron utilizando TGA y Calorimetría Diferencial de Barrido (DSC). Esta nueva membrana exhibió una absorción de agua mayor del 608% relacionada con la mejora del 36% en la capacidad de intercambio iónico y el incremento en 25.31% y 25.24% en la energía requerida para producir las transiciones termales inducidas por la adición del fluoropolímero sulfonado en bloque.

Estudio de envejecimiento de poliamida de alto impacto marca Deflex® en saliva artificial comercial / Deflex® brand high impact polyamide aging study in commercial artificial saliva

Este trabajo presenta los resultados de un estudio de envejecimiento natural y acelerado en saliva artificial, de un material para uso odontológico de la marca Deflex® a base de poliamida de alto impacto, según lo establece la norma UNE EN IS0 10993-13 (2009) (AU)

is work presents the results of the study of natural and accelerated aging in artificial saliva, of a material for dental use of the brand Deflex® based on high impact polyamide, as established by the standard UNE EN IS0 10993-13 (2009) (AU)

Preparation of polymer nanoparticles loaded with Syzygium aromaticum essential oil: an oral potential application / Preparación de nanoparticulas polimericas cargadas con aceite esencial de Syzygium aromaticum: una potencial aplicación oral

Due to the biological activities of Syzygium aromaticum essential oil, its incorporation in methacrylate polymeric (Eudragit E100) nanoparticles (NP), physical characterization, and antimicrobial essays were evaluated. The clove bears great potential for applications in dentistry. The oil was obtained by hydrodistillation and oil loaded NP using the nanoprecipitation method. Particle size and polydispersity index were determined by photon correlation spectroscopy, and physical morphology by electron microscopy. Loading capacity and in vitro eugenol release were evaluated by gas mass chromatography, and the antimicrobial activity of oil loaded-NP was calculated against Streptococcus mutans. Different chemical ingredients were characterized, and eugenol was the principal compound with 51.55%. Polymer content was directly related to NP homogenous size, which was around 150 nm with spherical morphology. A 73.2% loading capacity of eugenol was obtained. Oil loaded NP presented a fickian-type release mechanism of eugenol. Antimicrobial activity to 300 µg/mL was obtained after 24 h.

Debido a las actividades biológicas del aceite esencial de Syzygium aromaticum, se evaluó su incorporación en nanopartículas (NP) de metacrilato polimérico (Eudragit E100), su caracterización y ensayos antimicrobianos. El clavo tiene un gran potencial para aplicaciones en odontología. El aceite se obtuvo por hidrodestilación y las NP cargado de aceite utilizando el método de nanoprecipitación. El tamaño de partícula y el índice de polidispersidad se determinaron mediante espectroscopia de correlación fotónica y su morfología por microscopía electrónica. La capacidad de carga y la liberación de eugenol in vitro se evaluaron mediante cromatografía de gases en masa, y la actividad antimicrobiana se evaluó contra Streptococcus mutans. Se caracterizaron diferentes ingredientes químicos, siendo el eugenol el principal compuesto con 51.55%. El contenido de polímero se relacionó directamente con el tamaño homogéneo de NP, que fue de alrededor de 150 nm con morfología esférica. Se obtuvo un 73,2% de capacidad de carga de eugenol. El aceite cargado en NP presentó un mecanismo de liberación de eugenol de tipo fickiano. La actividad antimicrobiana a 300 µg/mL se obtuvo después de 24 h.

Synthesis of Renewable Poly(limonene): A Kinetic Modeling Study to Improve the Polymerization

Abstract Despite its potential in the production of polymers from renewable sources, D-limonene faces difficulties in its polymerization, resulting in low monomer conversion and molar mass. In order to investigate the non-ideality inherent kinetics, this work explores different modeling strategies for D-limonene radical polymerization, using benzoyl peroxide as initiator. The starting model considered the classical approach for conventional radical polymerization. This model was then corrected by including reaction orders different from the unit. After an analysis and choice of the best model, computer simulations were compared with experimental results from literature, validating the chosen approach. It was found that the process is drastically influenced by chain transfer reactions, presenting a non-ideal behavior. Finally, an analysis of distinct reaction conditions provided information on monomer conversion, molar mass and polymer dispersity, which could guide future research in the synthesis optimization. Higher molar mass poly(limonene) were obtained by simultaneously reducing the monomer and initiator concentrations.

Mechanical properties and surface roughness of polymer-based materials containing DCPD particles

Abstract The purpose of this study was to synthesize dicalcium phosphate dihydrate (DCPD) particles functionalized with triethylene glycol dimethacrylate (TEGDMA) through different routes by varying the receptor solution: ammonium phosphate (AP groups) or calcium nitrate (CN groups) and the moment in which TEGDMA was incorporated: ab initio (ab) or at the end of dripping the solution (ap). Two syntheses were performed without adding TEGDMA (nf). The particles were characterized by X-ray diffractometry, true density (using a helium pycnometer), surface area, and scanning electron microscopy. A 20 vol% of DCPD particles from the D, E, and F groups was added to the resin matrix to determine the degree of conversion (DC), biaxial flexural strength (BFS), the flexural modulus (FM), and surface roughness after an abrasive challenge (RA). A group with silanized barium glass particles was tested as a control. The data were submitted to ANOVA/Tukey's test (DC, BFS, and RA), and the Kruskal-Wallis test (FM) (alpha = 0.05). BFS values varied between 83 and 142 MPa, and the CN_ab group presented a similar value (123 MPa) to the control group. FM values varied between 3.6 and 8.7 GPa (CN_ab and CN_nf groups, respectively), with a significant difference found only between these groups. RA did not result in significant differences. The use of calcium nitrate solution as a receptor, together with ab initio functionalization formed particles with larger surface areas. Higher BFS values were observed for the material containing DCPD particles with a higher surface area. In general, the DC, FM, and RA values were not affected by the variables studied.

Two new mixed-ligand coordination polymers based on multi-N chelating ligand inhibit YAP expression and induce caspase-mediated spinal tumor cell apoptosis

Two new coordination polymers [Zn (bdc)(bpybzimH2)](DMF)0.5 (1, H2bdc=1,4-dicarboxybenzene, bpybzimH2=6,6′-bis-(1H-benzoimidazol-2-yl)-2,2′-bipyridine, DMF=N,N-dimethylformamide) and [Co (bpybzimH2)(sbc)]H2O (2, H2sbc=4-mercaptobenzoic acid) have been successfully prepared under solvothermal conditions using the multi-N chelating organic ligand bpybzimH2 as the foundational building block. In addition, the Cell Counting Kit-8 assay was conducted to evaluate the anti-proliferation activity of compounds 1 and 2 against human spinal tumor cells OPM-2. The cell viability curves showed that the two compounds have anti-proliferation activity on spinal tumor cells, and the activity of compound 1 is higher than compound 2. The annexin V-FITC/PI assay and western blot were used to detect the apoptotic percentage of OPM-2 cells incubated with compounds 1 and 2. The YAP protein expression and its role in cell apoptosis were further studied with qRT-PCR, immunoblotting, and flow cytometer.

Brittleness index and its relationship with materials mechanical properties: Influence on the machinability of CAD/CAM materials

Abstract: The aim of this study is to evaluate the machinability of four CAD/CAM materials (n = 13) assessed by brittleness index, Vickers hardness, and fracture toughness and interaction among such mechanical properties. The materials selected in this in vitro study are Feldspathic ceramic [FC], Lithium-disilicate glass ceramic [LD], leucite-reinforced glass ceramic [LR], and nanofilled resin material [RN]. Slices were made from the blocks following original dimensions 14 × 12 × 3 mm (L × W × H), using a precision slow-speed saw device and then surfaces were regularized through a polishing device. Brittleness index and fracture toughness were calculated by the use of specific equations for each one of the properties. The Vickers hardness was calculated automated software in the microhardness device. One-way Anova and Pearson's correlation were applied to data evaluation. LD obtained the highest values for brittleness index and was not significantly different from FC. LR presented statistically significant difference compared with RN, which had the lowest mean. Vickers hardness showed LD with the highest average, and no statistical difference was found between FC and LR. RN presented the lowest average. Fracture toughness showed FC and LR not statistically different from each other, likewise LD and RN. The brittleness index, considered also as the machinability of a material, showed within this study as positively dependent on Vickers hardness, which leads to conclusion that hardness of ceramics is related to its milling capacity. In addition, fracture toughness of pre-sintered ceramics is compared to polymer-based materials.

Sistemas de nanopartículas poliméricas II: estructura, métodos de elaboración, características, propiedades, biofuncionalización y tecnologías de auto-ensamblaje capa por capa (layer-by-layer self-assembly) / Polymeric nanoparticle systems: structure, elaboration methods, characteristics, properties, biofunctionalization and self-assembly layer by layer technologies

Los materiales poliméricos han sido ampliamente investigados para aplicaciones biomédicas, teniendo especial relevancia cuando se encuentran en forma de micro- y nano-partículas. Últimamente se ha ampliado su campo de aplicación al ser conjugados con péptidos y ácidos nucleicos, por lo tanto, el interés en el estudio de este tipo de materiales, así como también en la formulación de nanoestructuras funcionalizadas como materiales, dispositivos y vehículos de transporte de agentes terapéuticos ha aumentado. Las recientes investigaciones en nanosistemas se inspiran en fenómenos naturales que estimulan la integración de señales moleculares y la mimetización de procesos a nivel celular, de tejidos y órganos. Tecnológicamente, la capacidad de obtener nanoestructuras esféricas mediante la combinación de materiales que presenten propiedades distintas a las que ningún otro material individual posee por sí solo, es lo que hace que las nanocápsulas sean particularmente atractivas. Las potenciales ventajas de los sistemas de nanopartículas de tipo polimérico se destacan a lo largo de cada parte de este artículo de revisión. El presente artículo aborda los aspectos más relevantes sobre la estructura, composición y algunos métodos de elaboración de los sistemas nanoparticulados. Además, expone algunos de los trabajos más recientes, centrados en sistemas de nanopartículas basados en polímeros dirigidos a la administración de agentes, publicados en artículos especializados de investigación y revisiones durante los últimos años.

Polymeric materials have been extensively investigated for biomedical applications including micro- and nanoparticles. Modern advances have broadened horizons for application with peptides and nucleic acids. Therefore, interests increased in the formulation of materials, devices and vehicles for transporting therapeutic agents in functionalized nanostructures. Recent nano-systems are inspired by natural phenomena that stimulate the integration of molecular signals and the mimicking of natural cellular processes, at tissue and organ levels. Technologically, the ability to obtain spherical nanostructures, which combine different properties, that no other single material possesses on its own, makes nanocapsules particularly attractive. Potential advantages over polymer nanoparticulate systems are highlighted throughout each part of this review article. Here, we address the most relevant aspects of structure, composition and methods of formulation of nanoparticulate systems. In addition, we outline some of the more recent works focusing on nanosized preparations, based on agent-directed polymers, found in specialized research articles that have emerged in the recent years.

Sistemas de nanopartículas poliméricas i: de biodetección y monitoreo de glucosa en diabetes a bioimagen, nano-oncología, terapia génica, ingeniería de tejidos / regeneración a nano-odontología / Polymer nanoparticle systems: from biodetection and glucose monitoring in diabetes to bioimaging, nano-oncology, gene therapy, tissue engineering / regeneration to nano-dentistry

Nanotecnología es la ciencia que involucra la síntesis de materiales en escala entre 1-100 nm (nanomateriales) es aplicable en diferentes áreas tales como medio ambiente, electrónica, alimentos, energía, entre otros. Los campos que serán relevantes dentro de esta revisión y explicados en detalle son la nanomedicina y la nano-odontología. Actualmente, en estas áreas los tres principales temas en desarrollo son específicamente en el sub-área de la nanobiotecnología y corresponden a: sensorización (biosensores/biodetección), diagnóstico (biomarcadores/bioimagen) y transportes de genes, proteínas o fármacos (sistemas de intercambio controlado en blancos sistémicos versus localizados). También se han presentado avances en bioaplicaciones como modelamientos de membranas, marcaje celular, entrega de agentes a blancos específicos, estrategias para prevención de enfermedades, ingeniería de tejidos, regeneración de órganos, estrategias de inmunoensayos y nano-oncología. Este artículo de revisión pretende abordar algunos de los aportes más relevantes, que tienen algunos de los trabajos recientes, sobre los sistemas de nanopartículas, principalmente aquellos dirigidos a terapias en áreas como diabetes, nano-oncología, terapia de fármacos y genes, mediante la técnica layer-by-layer y autoensamblado, muy utilizados también en ingeniería de tejidos y regeneración tisular, junto a un breve resumen de los avances que existen en el campo de la nano-odontología.

Nanotechnology is the science that involves the synthesis of materials in scale between 1-100 nm (nanomaterials) and is applicable in different areas such as environment, electronics, food, energy, among others. The fields that will be relevant within this review and explained in detail are nanomedicine and nano-dentistry. Currently, in these areas, the three main topics under development are specifically in the sub-area of nanobiotechnology and correspond to: sensorization (biosensors / biosensing), diagnostics (biomarkers / bioimaging) and transport of genes, proteins or drugs (exchange systems) controlled in systemic versus localized targets). Advances have also been presented in bioapplications such as membrane modeling, cell marking, delivery of agents to specific targets, strategies for disease prevention, tissue engineering, organ regeneration, immunoassay strategies and nano-oncology. This review article aims to address some of the most relevant contributions, some of the recent work, on nanoparticle systems, mainly those aimed at therapies in areas such as diabetes, nanooncology, drug and gene therapy, through the layer-by-layer and self-assembled technique, also widely used in tissue engineering and tissue regeneration, together with a brief summary of the advances that exist in the field of nano-dentistry.

Bond strength between a polymer-infiltrated ceramic network and a composite for repair: effect of several ceramic surface treatments

Abstract: The effects of several ceramic surface treatments on bond strength of a polymer-infiltrated ceramic network and resin composite as repair material were evaluated. CAD-CAM blocks of a polymer-infiltrated ceramic network (Vita Enamic) were sliced and subjected to aging process, followed by embedding in acrylic resin. The bonding/repair area was treated as follows (n = 30): C- without treatment; UA- universal adhesive application; FM- 10% hydrofluoric acid and silane application; OM-airborne-particle abrasion with aluminum oxide and silane application; RP- tribochemical silica coating; and CA- surface grinding and application of universal adhesive. Composite resin cylinders were made on the treated surface. Specimens from each group were assigned randomly to two subgroups (n = 15) considering storage condition: Baseline (shear tests after 48 hours) or Storage (tests after 6 months under distilled water). The treated surfaces were analyzed by goniometry, roughness, and SEM. Two-way ANOVA and 1-way ANOVA were applied to analyze the bond data and roughness / contact angle data, respectively, followed by Tukey's test (α = 5%). Surface treatments and storage conditions affected bond strengths (p < 0.01). Surface grinding (CA) followed by universal adhesive promoted the highest value of bond strength (14.5 ± 4.8 MPa for baseline, 8.5 ± 3.4 MPa for storage) and the roughest ceramic surface. Grinding with silicon carbide paper (simulating diamond bur) followed by the application of a universal adhesive system is the best option for repairing fractures of the polymer-infiltrated ceramic network.

In vitro analysis of a local polymeric device as an alternative for systemic antibiotics in Dentistry

Abstract The development of a biodegradable material with antimicrobial properties for local applications is required in the prevention and treatment of infectious diseases. The objective of this study was to produce blends of poly-L-lactide acid (PLLA) synthetic polymer associated with several antimicrobials, as an alternative in the prevention and treatment of infections, as well as to evaluate its cytotoxicity, release of antimicrobials and inhibit bacteria growth. Blends of PLLA added with 20% Amoxicillin, Metronidazole, Clindamycin or Azithromicyn were used to produce Films (F) or Meshs (M) by casting and electrospinning methods, respectively. Standardized discs of the films and meshs were stored in buffer solutions (pH 5 or 7.4) and aliquots were analyzed by high performance chromatography (HPLC) during 168 hours. Cytotoxicity on human gingival fibroblasts was tested after 24, 48 and 72h by MTT reaction. The antimicrobial capacity was determined against P. gingivalis and S. pyogenes. The specimens were weighed after 3 and 6 months of storage for degradation analysis. SEM was performed to control interfaces and degradation. Antimicrobials presented a continuous and exponential drug release. Analysis showed that both M and F were able to inhibit S. pyogenes and P. gingivalis growth, indicating the release of active antimicrobial agents. The products were not toxic to the fibroblasts. Amoxicillin-film showed more degradation than PLLA at both pHs (p < 0.05), whereas Azithromycin-meshes were more degraded than PLLA at pH 7.4 (p < 0.05). PLLA association with antimicrobials is biocompatible and may represent a potential tool for the local delivery of antimicrobials.

Estudo da eficiência bactericida do biocida policloreto de dialildimetilamônio em materiais usados para confecção de próteses orais e faciais / Study of the bactericidal efficiency of the biocide poly(diallyldimethylammonium chloride) used in materials for the manufacture of oral and facial prostheses

As próteses faciais e intraorais tem um importante papel na devolução da estética e de algumas funções para os pacientes. Por meio da restauração da imagem corporal é possível reintegrá-lo a sociedade, resgatando assim a identidade do indivíduo. A boa condição dessas próteses é primordial para que estas possam exercer suas funções adequadamente e manter o local, onde estão inseridas, livre de infecções e inflamações. Portanto, a não formação de colônias e biofilmes bacterianos em materiais eleitos para confecção dessas próteses, trarão benefícios aos pacientes reabilitados. Visando isso, a presente dissertação verificou a capacidade de inclusão e a eficiência bactericida do biocida policloreto de dialildimetilamônio (PDADMAC) em resina acrílica autopolimerizável (RAAQ) e termopolimerizável (RAAT), e silicone de uso médico. Os resultados mostraram que o biocida PDADMAC quando dissolvido no tetrahidrofurano apresentou boa incorporação tanto nas resinas acrílicas, quimicamente ativas e termo ativas, quanto no silicone de uso médico e que apenas os corpos de prova que receberam 2 mililitros do PDADMAC em massa polimérica tiveram uma resposta bactericida eficaz.

The facial and intraoral prosthesis has an important role in the aesthetics and return of some functions to patients. Through restoration of the body image can reistante to can society , thus recovering the individual's identity . The good condition of these prostheses is essential so they can perform their function properly and maintain the the area where the prostheses are inserted free of infection and inflammation. Therefore, no formation of bacteria colonies and biofilms in the chosen materials for making these prostheses , will bring benefits to patients rehabilitated. The present work evaluated the capability of inclusion and the bactericidal efficiency of the biocide poly(diallyldimethylammonium chloride) ( pDADMAC ) of acrylic resin autopolymmerized ( RAAQ ) and thermal polymerized ( RAAT ) , and silicone medical use. The results showed that the biocide pDADMAC when dissolved in tetrahydrofuran presented a good incorporation in both acrylic resins and in the medical grade silicone and that only the samples that received 2 ml of pDADMAC in polymer had an effective bactericidal response.

In vivo performance of different scaffolds for dental pulp stem cells induced for odontogenic differentiation

Abstract This study was designed to determine the in vivo performance of three different materials as scaffolds for dental pulp stem cells (DPSC) undergoing induced odontogenic differentiation. An odontogenic medium modified by the addition of recombinant human bone morphogenetic protein 2 was used in the experimental groups to induce differentiation. Mesenchymal stem cell medium was used in the control groups. DPSC were transplanted onto the backs of mice via three scaffolds: copolymer of L-lactide and DL-lactide (PLDL), copolymer of DL-lactide (PDL) and hydroxyapatite tricalcium phosphate (HA/TCP). The expression levels of dentin sialo-phosphoprotein (DSPP), dentin matrix protein-1 (DMP1), enamelysin/matrix metalloproteinase 20 (MMP20) and phosphate-regulating gene with homologies to endopeptidases on X chromosome (PHEX) were analysed using RT-PCR. The expressions in the experimental groups were compared to those in the control groups. The transcript expressions at 6 and 12 weeks were significantly different for all scaffolds (p < 0.05), except for the expression of DSPP in the PLDL group with regard to the time variable. Although there was a decrease in the expression of enamelysin/MMP20 in PLDL and HA/TCP at 12 weeks, all other expressions increased and reached their highest level at 12 weeks. The highest DSPP expression was in the PDL group (p < 0.05). The highest expression of DMP1 was detected in the HA/TCP group (p < 0.05). The highest expression of PHEX was in the PLDL group (p < 0.05). Consequently, PLDL and PDL seemed to be promising scaffold candidates for odontogenic regeneration at least as HA-TCP, when they were applied with the DPSC induced for odontogenic differentiation.