The efficacy of immediate implantation of macroporous poly(N-[2-hydroxypropyl]-methacrylamide) hydrogel after laceration spinal cord injury in young rats / Eficacia de la implantación inmediata de hidrogel macroporoso de poli (N- [2-hidroxipropil] - metacrilamida) después de una lesión de la médula espinal en ratas jóvenes

SUMMARY: Spinal cord regeneration after mechanical injury is one of the most difficult biomedical problems. This article evaluates the effect of poly(N-[2-hydroxypropyl]-methacrylamide) hydrogel (PHPMA-hydrogel) on spinal cord regeneration in young rats after lateral spinal cord hemi-excision (laceration) at the level of segments T12-T13 (TrGel group). The locomotor function score (FS) and the paretic hindlimb spasticity score (SS) were assessed according to Basso-Beattie-Bresnahan (BBB) and Ashworth scales, respectively, and compared to a group of animals with no matrix implanted (Tr group). Regeneration of nerve fibers at the level of injury was evaluated at ~5 months after spinal cord injury (SCI). One week after the SCI induction, the FS on the BBB scale was 0.9±0.5 points in the Tr group and 3.6±1.2 points in the TrGel group. In the Tr group, the FS in 5 months was significantly lower than in 2 weeks after SCI, while no significant changes in FS were detected in the TrGel group over the entire observation period. The final FS was 0.8±0.3 points in the Tr group and 4.5±1.8 points in the TrGel group. No significant changes in SS have been observed in the TrGel group throughout the experiment, while the Tr group showed significant increases in SS at 2nd week, 6th week, 3th month and 5th month. The SS in 5 months was 3.6±0.3 points on the Ashworth scale in the Tr group and 1.8±0.7 points in the TrGel group. Throughout the observation period, significant differences in FS between groups were observed only in 5 weeks after SCI, whereas significant differences in SS were observed in 2, 3 and 6-8 weeks post-injury. Glial fibrous tissue containing newly formed nerve fibers, isolated or grouped in small clusters, that originated from the surrounding spinal cord matter have been found between the implanted hydrogel fragments. In conclusion, PHPMA-hydrogel improves recovery of the hindlimb locomotor function and promotes regenerative growth of nerve fibers. Further research is needed to clarify the mechanism of this PHPMA-hydrogel effect.

RESUMEN: La regeneración de la médula espinal después de una lesión mecánica es uno de los problemas biomédicos más difíciles. Este artículo evalúa el efecto del hidrogel de poli (N- [2-hidroxipropil] -metacrilamida) (PHPMA-hidrogel) sobre la regeneración de la médula espinal en ratas jóvenes después de la hemiescisión lateral de la médula espinal (lesión) a nivel de los segmentos T12 - T13 (Grupo TrGel). La puntuación de la función locomotora (FS) y la puntuación de espasticidad parética de las patas traseras (SS) se evaluaron de acuerdo con las escalas de Basso- Beattie-Bresnahan (BBB) y Ashworth, respectivamente, y se compararon con un grupo de animales sin matriz implantada (grupo Tr). Se evaluó la regeneración de las fibras nerviosas al nivel de la lesión ~ 5 meses después de la lesión de la médula espinal (LME). Una semana después de la inducción de SCI, el FS en la escala BBB fue 0,9 ± 0,5 puntos en el grupo Tr y 3,6 ± 1,2 puntos en el grupo TrGel. En el grupo Tr, el FS en 5 meses fue significativamente menor que en 2 semanas después de SCI, mientras que no se detectaron cambios significativos en FS en el grupo TrGel durante el período de observación. El FS final fue de 0,8 ± 0,3 puntos en el grupo Tr y de 4,5 ± 1,8 puntos en el grupo TrGel. No se han obser- vado cambios significativos en SS en el grupo TrGel durante el experimento, mientras que el grupo Tr mostró aumentos significativos en SS en la 2ª semana, 6ª semana, 3º mes y 5º mes. La SS en 5 meses fue de 3,6 ± 0,3 puntos en la escala de Ashworth en el grupo Tr y de 1,8 ± 0,7 puntos en el grupo TrGel. A lo largo del período de observación, se observaron diferencias significativas en FS entre los grupos solo en 5 semanas después de la LME, mientras que se observaron diferencias significativas en SS en 2, 3 y 6-8 semanas después de la lesión. Entre los fragmentos de hidrogel implantados se observó tejido fibroso glial que contenía fibras nerviosas recién formadas, aisladas o agrupadas en pequeños grupos, que se originaban a partir de la materia de la médula espinal circundante. En conclusión, PHPMA-hydrogel mejora la recuperación de la función locomotora de las patas traseras y promueve el crecimiento regenerativo de las fibras nerviosas. Se requieren más estudios para aclarar el mecanismo del efecto de hidrogel PHPMA.

Influence of fertilizer and hydrogel on physical-chemical attributes of substrate for seedling production / Influência de adubação e hidrogel nos atributos físico-químicos de substrato para produção de mudas florestais

The incorporation of the hydrogel into the substrate used in the forest nursery promotes improvements in its physical-chemical attributes. However, several factors influence the hydrogel efficiency, such as the increase of salts, promoted by fertilizer of the substrate. Therefore, this study aimed to evaluate the effects of the incorporation of fertilizer levels and hydrogel doses on the physical-chemical attributes of a substrate to produce forest seedlings. Different levels of basic fertilizer commonly used in the nursery (100%, 50% and 0%) and different doses of the hydrogel (0, 1, 2 and 3 g L-1) were incorporated into the substrate Tropstrato Florestal®, consisting of 12 treatments in a 3 x 4 factorial scheme. A sample of the substrate in each treatment was sent for analysis of its physical and chemical attributes. To evaluate the effect of the treatments on the physical-chemical attributes of the substrate, was used the multivariate principal components analyses. The levels of fertilizer and hydrogel doses were correlated with the attributes of the substrates obtained in each treatment. The incorporation of different fertilizer levels and hydrogel doses to the substrate modified their chemical and physical attributes. Fertilizers have influenced mainly the chemical attributes of the substrate, whereas hydrogels have influenced the physical attributes, mainly those related to water retention capacity and availability.

A incorporação do hidrogel ao substrato utilizado no viveiro florestal promove melhorias em seus atributos físico-químicos. Porém vários fatores influenciam na eficiência do hidrogel, como o aumento de sais, promovido pela adubação do substrato. Portanto, este estudo teve como objetivo avaliar os efeitos da incorporação de níveis de adubação e doses de hidrogel sobre os atributos físico-químicos de um substrato para a produção de mudas florestais. Foram incorporados ao substrato Tropstrato Florestal® diferentes níveis da adubação de base comumente utilizada no viveiro (100%, 50% e 0%) e diferentes doses do hidrogel (0, 1, 2 e 3 g L-1), consistindo em 12 tratamentos em esquema fatorial 3 x 4. Uma amostra do substrato em cada tratamento foi encaminhada para análise de seus atributos físicos e químicos. Para avaliar o efeito dos tratamentos sobre os atributos físico-químicos do substrato foi utilizada a análise multivariada de componentes principais. Os níveis de adubação e doses de hidrogel foram correlacionados com os atributos dos substratos obtidos em cada tratamento. A incorporação de diferentes níveis de adubação e doses de hidrogel ao substrato modificaram seus atributos químicos e físicos. A adubação influenciou principalmente os atributos químicos do substrato, enquanto que o hidrogel os atributos físicos, principalmente os relacionados à capacidade de retenção e disponibilidade de água.

Comparison of the Polymerization Shrinkage of Eclipse Resin for Prostheses with Conventional Acrylic Resins / Comparación de la Contracción de Polimerización de la Resina Eclipse para Prótesis con Resinas Acrílicas Convencionales

ABSTRACT: The objective of this study was to compare the polymerization shrinkage of Eclipse photopolymerization resin for prosthesis based on urethane dimethacrylate (UDMA) with that of three heat-cured acrylic resins based on polymethyl methacrylate (PMMA) after the polymerization process and immersion in water. A total of 40 prostheses were fabricated on a standard metallic upper edentulous model: group 1, Eclipse; group 2, Triplex hot; group 3, Veracril; and group 4, Lucitone 199. Subsequently, the polymerization contraction was tested using a microscope in which measurements were made in micrometres at 3 points located in the middle parts of the right and left sides and the middle part of the palate at three time points once the prosthesis was completed, after 30 days of immersion in water for 8 hours a day at a temperature of 37 °C, and after cutting the prosthesis at the level of the second premolar. ANOVA revealed that the contraction of the polymerization no statistically significant differences between the groups, (P> 0.05). The type of resin and its interaction with the processing method behaves similarly for all test resins. The Veracril heat-cured resin obtained the lowest contraction value in the three measurements (mm) and the highest value was obtained with the Eclipse photopolymerization resin. The Eclipse resin exhibited no lower polymerization shrinkage compared to conventional acrylic resins based on polymethyl methacrylate (PMMA), however it was not significantly affected by immersion in water.

RESUMEN: El objetivo de este estudio fue comparar la contracción de polimerización de la resina de fotopolimerización Eclipse para prótesis basadas en dimetacrilato de uretano (UDMA) con la de tres resinas acrílicas curadas con calor a base de polimetacrilato de metilo (PMMA) después del proceso de polimerización e inmersión en agua. Se fabricaron un total de 40 prótesis en un modelo edéntulo superior metálico estándar: grupo 1, Eclipse; grupo 2, triplex caliente; grupo 3, veracril; y grupo 4, Lucitone 199. Posteriormente, la contracción de la polimerización se probó utilizando un microscopio en el que se realizaron mediciones en micrometros en 3 puntos ubicados en las partes medias de los lados derecho e izquierdo y la parte media del paladar en tres puntos de tiempo una vez la prótesis se completó, después de 30 días de inmersión en agua durante 8 horas al día a una temperatura de 37 °C, y después de cortar la prótesis a nivel del segundo premolar. ANOVA reveló que la contracción de la polimerización no presenta diferencias estadísticamente significativas entre los grupos, (P> 0,05). El tipo de resina y su interacción con el método de procesamiento se comportan de manera similar para todas las resinas de prueba. La resina curada con calor Veracril obtuvo el valor de contracción más bajo en las tres mediciones (mm) y el valor más alto se obtuvo con la resina de fotopolimerización Eclipse. La resina Eclipse no mostró una contracción de polimerización menor en comparación con las resinas acrílicas convencionales basadas en polimetilmetacrilato (PMMA), sin embargo, no se vio afectada significativamente por la inmersión en agua.

Hidrogeles de polimerizacion in situ para la regeneracion de cartilago articular / In-situ hydrogel polymerization for articular cartilage regeneration

Una significativa cantidad de adultos jóvenes activos sufre lesiones condrales focales. Estas lesiones, si no se tratan, pueden progresar hacia la artrosis, que es una de las principales enfermedades musculoesqueléticas debilitantes y de gran carga económica que afectan a toda sociedad. Pese a los tratamientos quirúrgicos disponibles para la reparación de defectos condrales focales sintomáticos que mejoran la calidad de vida a mediano plazo, hay un mayor riesgo de progresión hacia la artrosis prematura. Los tratamientos biológicos (células madre, bioingeniería tisular) han avanzado a grandes pasos en los últimos años. La bioingeniería es un área que ha progresado en la regeneración de cartílago articular y que potencialmente podría progresar en el terreno de tratamientos articulares, promoviendo la regeneración y evitando la degeneración. Las células madre y los hidrogeles pueden proveer un tejido símil biológico de comportamiento dinámico-funcional equivalente que induce la regeneración tisular al ser degradado y reemplazado gradualmente. El abordaje consiste en colocar un hidrogel precursor o un biomaterial tridimensional impreso dentro del defecto condral por ocupar para inducir la regeneración. Esta revisión se focaliza en el uso actual y futuro de hidrogeles y bioimpresión tridimensional para la regeneración de cartílago articular en el tratamiento de lesiones condrales focales y proporciona datos preliminares de dos estudios piloto en animales. Nivel de Evidencia: V

A significant number of young active adults are affected by focal chondral lesions. These lesions, if left untreated, will progress to osteoarthritis (OA). OA is one of the main debilitating musculoskeletal diseases and leads to a high economic and social burden. Despite surgical cartilage repair for focal chondral lesions, which improve patient-reported outcomes at short- and mid-term, there is a risk of early OA progression. Biological treatments (i.e., stem-cell therapy, bioengineering) have made great progress in the last years. Tissue engineering is an evolving field for articular cartilage repair which could potentially be used for the treatment of focal chondral lesions, promoting regeneration and preventing joint surface degeneration. Stem cells and hydrogels may provide a functional, dynamic and biologically equivalent tissue that promotes tissue regeneration while being gradually degraded and replaced. The standard approach to tissue engineering consists in delivering cells within a hydrogel or a three-dimensional printed biomaterial scaffold into the chondral lesion to induce regeneration. This review focuses on the current and future use of hydrogels and tissue scaffold bioprinting for the treatment of focal chondral lesions, and provides preliminary data from two pilot animal studies. Level of Evidence: V

Avaliação antimicrobiana da nanoquitosana incorporada no hidrogel de PVA e propilenoglicol / Antimicrobial evaluation of PVA and propylene glycol hydrogel integrated nanochitosan

A nanoquitosana (NQ) possui potencial antimicrobiano contra microrganismos causadores de Doenças Transmitidas por Alimentos. Este trabalho busca determinar o efeito antimicrobiano da NQ em hidrogéis para substituir os produtos assépticos e sanitizantes convencionais. O hidrogel de propilenoglicol foi testado em superfície de aço inox em E. coli, apresentando crescimento de 303±53 UFC, inferior ao controle 481,5±62,5 UFC. O gel de PVA foi testado pelo método de disco-difusão contra E. coli, com halo de inibição de 2,7±0,2 cm (NQ 71,43 µg.mL-1) e 2,3±0,3 cm (NQ 142,85 µg.mL-1), e S. typ, com halo de inibição de 3,0±0,2 cm e 2,8±0,2 cm, com NQ 71,43 µg.mL-1 e 142,85 µg.mL-1, respectivamente. Os resultados indicam potencial uso da NQ em produtos sanitizantes, para isso são necessários testes toxicológicos e caracterização das nanoestruturas.

Avaliação antimicrobiana de hidrogel de PVA e gel de Propilenoglicol incorporado com Nanopartículas de Prata como sanitizantes / Antimicrobial evaluation of PVA hydrogel and propilene glycol incorporated with silver nanoparticles

As Doenças Transmitidas por Alimentos causam diversos problemas de saúde e prejuízos econômicos e tem como principal causa a má manipulação dos alimentos. Portanto, é necessário o uso de estratégias de higiene pessoal e de sanitização das instalações e equipamentos. Pensando nisso, este trabalho apresenta a síntese e análise antimicrobiana por disco-difusão e contagem bacteriana de um gel sanitizante a base de Polietileno Glicol e um hidrogel de PVA com a incorporação de Nanopartículas de Prata (AgNP). Para o primeiro gel, com AgNP, o resultado foi quatro vezes maior que o controle. Para o segundo gel, o aumento na concentração de AgNP garantiu uma maior inibição bacteriana. Os resultados obtidos comprovam a potencialidade deste sanitizante para aplicação industrial, comercial e laboratorial.

Varying the vegetative and morphological traits of Thymus kotschyanus L. submitted to potassium silicate nanoparticles, superabsorbent hydrogel, effective microorganisms, and animal manure / Variação das características vegetativas e morfológ icas de thymus kotschyanus l. submetida a nanopartículas de silicato de potássio, o hidrogel superabsorvente, os microorgan ismos efetivos e o esterco animal

To study the effects of some new facilitators on the vegetative and morphological traits of Thymus kotschyanus, nine treatments were tested in the experimental rangeland field at the University of Mohaghegh Ardabili, Ardabil, Iran. Treatments included control, potassium silicate nanoparticles (PSN) with two levels of 500 and 1000 mg/lit, superabsorbent hydrogel (SH) with two levels of 10 and 30 g/kg, animal manure (AM) with two levels of 100, 200 g/kg, and effective microorganisms (EM) with two levels of 1 and 2%. Data were subjected to one-way analysis of variance (ANOVA). Results of mean comparisons of treatments for Thymus kotschyanus characteristics showed that the highest amount of studied traits were observed in the treated SH 30 g/kg. These traits include plant height (19.44 cm), basal area (4.66 cm), canopy cover (99.11%), number of secondary branches (9.44) and depth of rooting (16.49 cm), aerial parts volume (26.77 cm3), root volume (17.66 cm3), aerial parts fresh weight (14.40 g), aerial parts dry weight (7.18 g), root fresh weight (3.98 g), and root dry weight (2.07 g). In general, the impact of treatments on Thymus growth traits were ranked as follows: SH 30 g/kg, PSN 1000 mg/lit, AM 200 g/kg, SH 10 g/kg, PSN 500 mg/lit, AM 100 g/kg, EM 2%, and EM 1%. In addition,the lowest plant traits were found in control. Overall, it is recommended extending the cultivation of this native medicinal plant by considering ecological conditions in each region. In addition, to promote the establishment and facilitate the growth of planted species, it is recommended using the facilitators utilized in the present work.

Para estudar os efeitos de alguns novos facilitadores sobre as características vegetativas e morfológicas de Thymus kotschyanus L., nove tratamentos foram testados no campo experimental de pastagens na Universidade de Mohaghegh Ardabili, Ardabil, Irã. Os tratamentos incluíram controle, nanopartículas de silicato de potássio (PSN) com dois níveis de 500 e 1000 mg/L, hidrogel superabsorvente (SH) com dois níveis de 10 e 30 g/kg, esterco animal (AM) com dois níveis de 100 e 200 g/kg e microorganismos efetivos (EM) com dois níveis de 1 e 2%. Os dados foram submetidos a uma análise de variância unidirecional (ANOVA). Os resultados das comparações médias dos tratamentos para as características de Thymus kotschyanus L. mostraram que a maior quantidade das características estudadas foi observada no tratamento com SH 30 g/kg. Essas características incluem altura de plantas (19,44 cm), área basal (4,66 cm), cobertura de dossel (99,11%), número de ramos secundários (9,44) e profundidade de enraizamento (16,49 cm), volume de partes aéreas (26,77 cm3), volume de raiz (17,66 cm3), peso fresco de partes aéreas (14,40 g), peso seco de partes aéreas (7,18 g), peso fresco de raiz (3,98 g) e peso seco de raiz (2,07 g). Em geral, o impacto dos tratamentos nas características de crescimento de Thymus foi classificado da seguinte forma: SH 30 g/kg, PSN 1000 mg/L, AM 200 g/kg, SH 10 g/kg, PSN 500 mg/L, AM 100 g/kg, EM 2% e EM 1%. Além disso, as características mais baixas da planta foram encontradas no controle. Em geral, recomenda-se estender o cultivo desta plantamedicinal nativa considerando as condições ecológicas em cada região. Além disso, para promover o estabelecimento e facilitar o crescimento de espécies plantadas, recomenda-se utilizar os facilitadores utilizados no presente trabalho.

Desenvolvimento de biomateriais à base de quitosana: matriz de fibras eletrofiadas para regeneração tecidual e de hidrogel coacervado para entrega controlada de fármaco / Development of chitosan-based biomaterials: electrospun fiber matrix for tissue regeneration and coacervate hydrogel for controlled drug delivery

Os atuais avanços no desenvolvimento de biomateriais caminham para 2 áreas promissoras: a de regeneração tecidual e a de entrega controlada de fármacos. Assim, o presente estudo objetivou a síntese e caracterização de diferentes matrizes (fibras e hidrogel) à base de quitosana, a fim de se obter materiais biomiméticos para atuação em ambas áreas. Para regeneração, delineou-se a síntese de um arcabouço de fibras de quitosana com e sem cristais de nanohidroxiapatita onde, para isso, foram eletrofiadas soluções de quitosana (Ch) e de quitosana com nanohidroxiapatita (ChHa). Os espécimes de Ch apresentaram maior homogeneidade e maior diâmetro médio de fibras (690 ± 102 nm) que ChHa (358 ± 49 nm). No teste de viabilidade celular e na atividade da fosfatase alcalina não houve diferença estatística entre os grupos experimentais (Ch e ChHa), porém ambos diferiram do grupo controle (p < 0,001). Para o âmbito de liberação de fármacos, sintetizou-se, pela técnica de emulsão, dois tipos de hidrogéis: o primeiro, uma mistura da fase aquosa da solução de Ch (1 mL) e da solução de DNA (1 mL) (1:1) e o segundo, mistura da fase aquosa da solução de Ch (1 mL) e solução de Pectina (1 mL) (1:1). Ambas misturas foram realizadas em álcool benzílico (5 mL) com instrumento de dispersão de alto desempenho (31-34000 rpm min-1 por 5 min). Após a obtenção dos géis, 20mg de cada grupo foram imersos em uma solução aquosa de Própolis Verde (PV), na concentração de 70 µg/mL por 2 h e a cinética de liberação do PV foi analisada a 25 e 37oC em água e saliva artificial. Os espécimes obtidos foram liofilizados e depois caracterizados físicoquimicamente. A presença de pectina e de DNA foi comprovada por FTIR. A sorção de PV induziu uma modificação significativa da superfície do gel. Constatou-se uma separação de fases entre a quitosana e o DNA. A eficiência do encapsulamento não mudou significativamente entre 25 e 37oC. A cinética de liberação na água ou na saliva apresentou um mecanismo de duas etapas. E os resultados biológicos exibiram que esses materiais são aceitáveis no ambiente biológico. Assim, conclui-se que a matriz de fibras de quitosana com nHAp é capaz de promover diferenciação celular e a matriz de hidrogel de quitosana com Pectina ou DNA possui potencial para a liberação controlada de fármacos(AU)

Current advances in biomaterial development are moving to 2 promising areas: tissue regeneration and controlled drug delivery. Thus, the present study aimed the synthesis and characterization of different matrices (fibers and hydrogel) based on chitosan, in order to obtain biomimetic materials for performance in both areas. For regeneration, the synthesis of a scaffold of chitosan fibers with and without nanohydroxyapatite crystals was delineated, where chitosan (Ch) and chitosan with hydroxyapatite (ChHa) solutions were electrospun. Ch specimens presented higher homogeneity and larger mean fiber diameter (690±102nm) than ChHa (358 ± 49nm). In the cell viability test and alkaline phosphatase activity there was no statistical difference between the experimental groups. (Ch and ChHa), but both differed from the control group (p < 0,001). For the drug release scope, two types of hydrogels were synthesized by the emulsion technique: the first, a mixture of the aqueous phase of Ch solution (1 mL) and DNA solution (1 mL) (1:1) and the second, mixture of the aqueous phase of the Ch solution (1mL) and Pectin solution (1 mL) (1:1). Both mixtures were performed in benzyl alcohol (5 mL) with high performance dispersion instrument (31-34000 rpm min-1 for 5 min). After obtaining the gels, 20mg from each group were immersed in an aqueous solution of Propolis Green (PV), at a concentration of 70 µg/mL for 2 h and the release kinetics of PV were analyzed at 25 and 37oC in water and artificial saliva. The obtained specimens were lyophilized and then physically-chemically characterized. The presence of pectin and DNA was confirmed by FTIR. PV sorption induced a significant modification of the gel surface. A phase separation was found between chitosan and DNA. Encapsulation efficiency did not change significantly between 25 and 37oC. The release kinetics in water or saliva presented a two-step mechanism. And the biological results showed that these materials are acceptable in the biological environment. Thus, it is concluded that the nHAp chitosan fiber matrix is capable of promoting cell differentiation, whereas the chitosan hydrogel matrix with Pectin or DNA are potential biomaterials for controlled drug release(AU)

Fabrication of hydrophilic medical catheter with hydrogel grafting and the in vivo evaluation of its histo-compatibility / 生物医学工程学杂志

The biocompatible hydrogel was fabricated under suitable conditions with natural dextran and polyethylene glycol (PEG) as the reaction materials. The oligomer (Dex-AI) was firstly synthesized with dextran and allylisocyanate (AI). This Dex-AI was then reacted with poly (ethyleneglycoldiacrylate) (PEGDA) under the mass ratio of 4∶6 to get hydrogel (DP) with the maximum water absorption of 810%. This hydrogel was grafted onto the surface of medical catheter via diphenyl ketone treatment under ultraviolet (UV) initiator. The surface contact angle became lower from (97 ± 6.1)° to (25 ± 4.2)° after the catheter surface was grafted with hydrogel DP, which suggests that the catheter possesses super hydrophilicity with hydrogel grafting. The evaluation after they were implanted into ICR rats subcutaneously verified that this catheter had less serious inflammation and possessed better histocompatibility comparing with the untreated medical catheter. Therefore, it could be concluded that hydrogel grafting is a good technology for patients to reduce inflammation due to catheter implantation, esp. for the case of retention in body for a relative long time.

Estudo da gelificação do produto de digestão de ECM descelularizada para uso em engenharia de tecidos / Gelation study of extracellular matrix digestion products for tissue engineering

Os implantes utilizados para regeneração tecidual ainda falham na tentativa de mimetizar as propriedades da matriz extracelular (ECM), o que compromete a viabilidade e aplicabilidade do material. Além disso, permanece o desafio de desenvolver um método de aplicação minimamente invasivo para evitar danos teciduais adicionais (Badylak et al., 2015; Crapo et al., 2011; Xing et al., 2014). Assim, o objetivo do projeto é desenvolver um hidrogel injetável composto de ECM de pericárdio, tendão e osso bovino enzimaticamente digerida e reticulada com glutaraldeído, ésteres ativados de NHS e derivados de polietilenoglicol (PEG). O protocolo de digestão foi modificado de Willians (Williams et al., 2015), utilizando tripsina, pepsina e colagenase. A quantificação de GAGs e peptídeos mostrou que, independentemente do substrato e enzima utilizados, o processo em etapas gerou uma maior concentração de estruturas em relação ao processo contínuo. Adicionalmente, a análise de dicroísmo circular mostrou que o processo em etapas preservou mais estruturas secundárias. O perfil proteico das ECMs foi analisado como descrito em Flores (Flores et al., 2016), e foi verificado que ele é altamente diverso e tecido - específico. A ECM do pericárdio possui 94 tipos diferentes de proteínas, seguidas pela ECM do tendão (48) e pela ECM óssea (35), sendo o colágeno α1 (1) e o colágeno α2 (1) presentes em todas elas. Além disso, os produtos digeridos ECMp aumentaram a proliferação e diferenciação de células-tronco mesenquimais da medula óssea a osteoblastos maduros. A cinética do processo de gelificação, bem como as propriedades mecânicas do gel são dependentes do tipo de agente reticulante, assim como da concentração da gelatina. Este novo material é altamente personalizável e adaptável à aplicação biológica desejada

The implants used for tissue regeneration still fail to mimic properties of extracellular matrix. It compromises the material viability and applicability. Furthermore, the challenge to manufacture a minimally invasive delivery system for it to avoid extra tissue damage still remains (Badylak et al., 2015; Crapo et al., 2011; Xing et al., 2014). Thus, the project goal is to develop an injectable hydrogel composed of pericardium, tendon and bovine bone ECM enzymatically digested and crosslinked with glutaraldehye, activated esters of NHS and polyethylene glycol (PEG) derivatives. The digestion protocol was modified from Willians (Williams et al., 2015), using trypsin, pepsin and collagenase as lytic enzymes. GAGs and peptides quantification showed that regardless of the substrate and enzyme, the stepwise process yields a higher amount of GAGs and peptides in comparison with the continuous process. In addition, circular dicroism analysis showed that the stepwise process preserves more secondary structures of proteins. ECMs protein profile was analyzed as in Flores (Flores et al., 2016) and verified that it is the highly diverse and tissue-specific. Pericardium ECM has 94 different types of proteins, followed by tendon ECM (48) and bones ECM (35), being collagen α1(1) and collagen α2(1) present in all of them. Furthermore, the ECMp digested products enhanced bone marrow mesenchymal stem cells proliferation and differentiation in mature osteoblast. The kinetics of the gelification process, as well as mechanical properties of the gel is dependent of the type of crosslinker and concentration of gelatin. This new material is highly customizable and adaptable to the biological application

Encapsulation of specific Salmonella Enteritidis phage f3αSE on alginate-spheres as a method for protection and dosification

Background: Bacteriophages have been proposed as an alternative to control pathogenic bacteria resistant to antibiotics. However, they are not extensively used due to different factors such as vulnerability under environmental conditions and the lack of efficient administration methods. A potential solution is the encapsulation of bacteriophages in hydrogel polymers to increase their viability and as a controlled release method. This work describes the use of alginate-Ca+2 matrixes as mechanisms for protection and dosification of the phage f3αSE which has been successfully used to prevent infections produced by Salmonella Enteritidis. Results: The viability of the pure phage is reduced in near 100% after 1-h incubation at pH 2 or 3. However, the encapsulated phage remains active in 80, 6% at pH 3, while no differences were observed at pH 2, 4 or 7. Exposition of f3αSE to different T° showed that the viability of this phage decreased with increased T° to near 15% at 60°C, while the encapsulated phage remains with 50% viability at same temperature. Finally, the encapsulation of phages showed to extend their presence for 100 h in the medium compared to non-encapsulated phages in a water flow system, which simulate automatic birdbath used in poultry industry, maintaining the phage concentration between 102 and 104 PFU/mL during 250 h. Conclusions: Encapsulation in alginate-Ca+2 spheres can be a good alternative to extend viability of phages and can be used as a phage method dosification method in water flow systems.

Acute toxicity study of a polysaccharide based hydrogel from linseed for potential use in drug delivery system

ABSTRACT Linseed hydrogel (LSH) was evaluated by acute toxicity for its potential application in oral drug delivery design. White albino mice and rabbits were divided in four groups (I-IV) and different doses of LSH (1, 2 and 5 g/kg body weight) were given except to the control group (I) that was left untreated. Rabbits were monitored for eye irritation, acute dermal toxicity and primary dermal irritation, whereas, body weight, food and water consumption, hematology and clinical biochemistry, gross necropsy and histopathology of vital organs were scrutinized in mice. LSH was considered safe after eye irritation test as no adverse signs or symptoms were seen in the eye. In dermal toxicity and irritation study, skin of treated rabbits was found normal in color without any edema or erythema. After oral administration, there was no sign of any abnormalities in treated group animals (II-IV). The hematology and clinical biochemistry of treated group animals was comparable with the control group. Histopathology of vital organs has not shown any lesion or abnormalities. In the light of these outcomes, it can be concluded that LSH is not a hazardous biomaterial and could be incorporated as an excipient in oral and dermal preparations.

Experimental study on the in vitro osteogenic differentiation of dental pulp stem cells encapsulated in Pluronic F-127 hydrogel / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the biocompatibility and viability of nonionic triblock copolymer Pluronic F-127 as a cell scaffold for osteogenic differentiation of dental pulp stem cells(DPSC).</p><p><b>METHODS</b>DPSC were obtained via enzymatic digestion method and purified bylimited dilution method. The freeze dried hydrogel of 20% Pluronic F-127 was prepared and itsstructurewas observed usingscanning electron microscopy(SEM). After the encapsulation of cells of passage 3 in Pluronic F-127, the effects of hydrogel on the proliferations of DPSC were assessed with methyl thiazolyl terazolium(MTT) after one day and 3, 5, 7 days of incubations, respectively. On day 14, osteogenic abilities of DPSC encapsulated in the hydrogel were estimated by means of alizarin red S, immunocytochemical staining and real-time quantitative PCR(RT-qPCR).</p><p><b>RESULTS</b>DPSC were isolated and cultured successfully in the present study. SEM observations showed that porous structures which might be suitable for cell culture. A570 values of MTT were then normalized. A570 values of the cells in 2D cultures were 0.30±0.06, 0.30±0.17, 0.35±0.04 and 0.25±0.06 and A570 values of DPSC in 3D cultures were 0.36±0.06, 0.54±0.18, 0.70±0.10 and 0.32±0.10 on day 1, 3, 5 and 7, respectively. A570 value peaks were found on day 5 in both groups. The proliferation of 3D cultured DPSC was higher than that of 2D cultured cells(P<0.05). After 14 days of osteogenic induction, there were no calcium nodules observed in the control group and the numbers of calcium nodulesin the 2D and 3D groups had no significant difference(P>0.05). Inmmunocytochemical staining demonstrated strong expression of osteoblast marker Runt-related transcription factor 2(RUNX2), type Ⅰ collagen(Col-Ⅰ) and relatively low expression of osteocalcin(OCN). Moreover, RT-qPCR showed no differences between the relative expression of ALP, RUNX-2, OCN in the 2D and 3D groups (P>0.05), but a higher relative expression of Col-Ⅰ was observed in the 3D group(P=0.023).</p><p><b>CONCLUSIONS</b>Pluronic F-127 is a promising cell scaffold or cell carrier for the osteobalst differentiation of dental pulp stem cells.</p>

Retinoic acid liposome-hydrogel: preparation, penetration through mouse skin and induction of F9 mouse teratocarcinoma stem cells differentiation

Retinoic acid (RA), a metabolite of retinol, is one of the most biologically active forms of retinoid and plays vital roles in embryonic development and in the regulation of cell proliferation and differentiation. Knowing that liposomes simulate cell membranes and that hydrogel is an ideal delivery vehicle for topical medicine, liposome-hydrogel is a novel preparation that has synergistic advantages over each component separately. Our objective was to investigate the characteristics of RA liposome-hydrogel. For quality control of the RA-loaded liposomes, we measured their morphology, particle size, Zeta-potential, and entrapment efficiency. Then we determined the viscosity of RA liposome-hydrogel. Next, the diffusion through mouse skin was explored, followed by investigation of the mRNA expression levels of Ker18, REX1, and α-FP using Q-PCR. The results showed that RA liposome-hydrogel penetrates the mouse skin effectively. The permeation rates were: Qn (%) of RA liposome-hydrogel < Qn(%) of RA-loaded liposome < Qn (%) of RA. The mRNA expression levels were dose-dependent and the effective dose decreased between vehicles due to their different release rates. F9 mouse teratocarcinoma stem cells were an ideal model to explore the mechanism of RA liposome-hydrogel in stem cell differentiation.

O ácido retinóico (RA) é um metabolito de retinol. Ele também é uma das formas mais biologicamente ativas de retinóide. Desempenha papel vital no desenvolvimento embrionário e na regulação da proliferação e diferenciação celular. Sabendo-se que lipossomas simulam a membrana das células e que hidrogel é um sistema ideal para o medicamento tópico, o lipossoma-hidrogel é uma nova preparação, que apresenta vantagens sinérgicas em relação a cada um dos componentes separados. Nosso objetivo foi investigar as características de RA lipossoma-hidrogel. A fim de controlar a qualidade do lipossoma carregado com RA, medimos morfologia, tamanho das partículas, potencial zeta e eficiência de retenção. Em seguida, determinou-se a viscosidade de RA lipossoma-hidrogel. Em seguida, avaliou-se a sua difusão através da pele de camundongos, seguida da investigação dos níveis da expressão de mRNA de Ker18, REX e de α-FP, utilizando-se Q-PCR. Os resultados mostraram que RA lipossoma-hidrogel pode penetrar na pele do camundongo de forma eficaz. As taxas de permeação foram: Qn (%) de RA lipossoma-hidrogel<Qn(%) de lipossoma RA- carregado <Qn (%) de RA. Os níveis de expressão de mRNA foram dependentes de dose e a dose efetiva diminuiu entre os veículos devido às diferentes taxas de liberação, As células estaminais de teratocarcinoma F9 de camundongo mostraram-se como modelo ideal para explorar o mecanismo de diferenciaçãode células tronco pelo RA lipossoma-hidrogel.

Glucan HBP-A increase type II collagen expression of chondrocytes in vitro and tissue engineered cartilage in vivo / 中国结合医学杂志

<p><b>OBJECTIVE</b>Although chondroprotective activities have been documented for polysaccharides, the potential target of different polysaccharide may differ. The study was aimed to explore the effect of glucan HBP-A in chondrocyte monolayer culture and chondrocytes-alginate hydrogel constructs in vivo, especially on the expression of type II collagen.</p><p><b>METHODS</b>Chondrocytes isolated from rabbit articular cartilage were cultured and verified by immunocytochemical staining of type II collagen. Chondrocyte viability was assessed after being treated with HBP-A in different concentrations. Morphological status of chondrocytes-alginate hydrogel constructs in vitro was observed by scanning electron microscope (SEM). The constructs were treated with HBP-A and then injected to nude mice subcutaneously. Six weeks after transplantation, the specimens were observed through transmission electron microscopy (TEM). The mRNA expressions of disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTs-5), aggrecan and type II collagen in both monolayer culture and constructs were determined by real time polymerase chain reaction (PCR). The expression of type II collagen and matrix metalloproteinases-3 (MMP-3) in chondrocyte monolayer culture was also tested through Western blot and enzyme linked immunosorbent assay (ELISA), respectively.</p><p><b>RESULTS</b>MMP-3 secretion and ADAMTs-5 mRNA expression in vitro were inhibited by HBP-A at 0.3 mg/mL concentration. In morphological study, there were significant appearance of collagen in those constructs treated by HBP-A. Accordingly, in both chondrocyte monolayer culture and chondrocytes-alginate hydrogel constructs, the expression of type II collagen was increased significantly in HBP-A group when compared with control group (P<0.001).</p><p><b>CONCLUSIONS</b>The study documented that the potential pharmacological target of glucan HBP-A in chondrocytes monolayer culture and tissue engineered cartilage in vivo may be concerned with the inhibition of catabolic enzymes MMP-3, ADAMTs-5, and increasing of type II collagen expression.</p>

Palhiço, polímero hidrogel e sistemas de plantio nos parâmetros de biometria, tecnologia, energia e produtividade de cana-de-açúcar / Straw, hydrogel polymer, and planting system on the parameters of biometrics, technology, energy and productivity of sugarcane hidroabsorvente

O objetivo deste trabalho foi verificar o efeito do palhiço, sistema de plantio e doses de polímero hidrogel nos parâmetros biométricos, tecnológicos, de produtividade e energéticos. O estudo foi realizado em soqueira de cana-de-açúcar, cultivar RB 86 7515. O solo do experimento foi caracterizado como Argissolo Vermelho-Amarelo Distroférrico, típico A moderado, textura médio-argilosa e o clima da região classificado como em Aw. O modelo estatístico utilizado foi fatorial com parcelas subdivididas (2x4x4), sendo dois os sistemas de plantios utilizados (leira e sulco), quatro doses do polímero hidroabsorvente, sendo cada dose subdividida em quatro tratamentos utilizando quantidades diferentes de palhiço como cobertura vegetal. O palhiço em cobertura afetou os parâmetros biométricos, principalmente quando em interações com plantio em leira. Não afetou a produtividade e interagindo com doses de polímeros elevou a bioenergia, sendo as quantidades de 5 a 10 t ha-1 de palhiço com 53,33 kg ha-1 de polímeros as melhores para bioenergia. Os sistemas de plantio testados afetam a biometria, tecnologia, bioenergia e ATR (Açúcar Total Recuperável, que corresponde à quantidade de açúcar disponível na matéria-prima subtraída das perdas estimadas no processamento industrial), com dose de 53,33 kg ha-1 de polímero e não afetam a produtividade. As doses de polímeros alteram a biometria (medidas dos órgãos vegetais, bem como as devidas taxas de desenvolvimento), principalmente em leira, sendo a dose de 53,33 kg ha-1 a que proporcionou melhores ATR, não afetando a produtividade nem a bioenergia.

The objective of this study was to investigate the effect of straw, planting system and hydrogel polymer on biometrics, technologies, productivities and energy. The study was conducted in the ratoon sugarcane, cultivar RB 86 7515. The soil was characterized as Ultisol Distroferric typical A moderate, medium-loamy texture and the climate in the region classified as Aw. The statistical model used was split plot factorial (2x4x4), two planting systems used (windrow and groove), four doses of hydrogel polymer, each subdivided into four dose treatments using different amounts of straw in cover. The straw in coverage affects biometric parameters, especially when interactions with planting. Doesn't affect productivity and interacting with doses of polymers increases bioenergy, and the amounts 5-10 t ha-1 of straw with 53.33 kg ha-1 of polymers are the best for bioenergy. The planting systems affect biometrics, technology, bioenergy and TRS. Doses of 53.33 kg ha-1 of polymer and not affect productivity. Doses of polymers alter biometrics, especially in windrow, and 53.33 kg ha-1 promote the best TRS doesn't affecting productivity or bioenergy.

Preparation of novel biodegradable pHEMA hydrogel for a tissue engineering scaffold by microwave-assisted polymerization

OBJECTIVE@#To prepare a novel biodegradable poly(2-hydroxyethylmethacrilate) (pHEMA) hydrogel as tissue engineering scaffold.@*METHODS@#The pHEMA hydrogel was synthesized by microwave-assisted polymerization using 2-hydroxyethyl methacrylate (HEMA) as the raw material, potassium persulfate as the initiator, and PCLX as the cross-linking additive. The hydrogels was characterized with FTIR and NMR spectroscopy. The physical and chemical properties of the prepared hydrogel were evaluated, and its degradation performance was tested. The cytotoxicity of the optimum composite hydrogel was measured by an MTT assay to confirm the feasibility of its use in tissue engineering.@*RESULTS@#The optimum conditions under which the hydrogel was prepared by microwave-assisted polymerization are as follows: 1.5 g cross-linking additive, 0.3 g initiator, reaction temperature of 80 °C, and microwave power of 800 W. Degradation studies showed good degradation profiles with 75% in 17 days. Additionally, the hydrogels did not elicit any cytotoxic response in in vitro cytotoxic assays.@*CONCLUSION@#A biodegradable pHEMA hydrogel was successfully prepared by microwave-assisted polymerization, as confirmed from FTIR and NMR results. The hydrogel shows promising applications in tissue engineering, and its healing ability and biocompatibility will be evaluated in detail in the future.

Extração de bromelina dos resíduos de abacaxi ( Ananas comosus ) por sistemas de duas fases aquosas e sua aplicação em hidrogel polimérico / Extraction of bromelain from pineapple waste ( Ananas comosus ) by aqueous two-phase systems and its application in polymeric hydrogels

Bromelina é um nome coletivo para enzimas proteolíticas encontradas no talo, fruto e folhas do abacaxi (Ananas comosus Merr). A bromelina possui propriedades anti-inflamatórias, de debridamento, entre outras. Para a produção da bromelina deve-se, preferencialmente, usar resíduos do abacaxi, visto que os produtos do fruto têm aplicação comercial. Este trabalho teve como objetivo a extração de bromelina a partir de cascas de abacaxi através de sistema de duas fases aquosas (SDFA), e sua aplicação em hidrogel polimérico. Foram realizados estudos de estabilidade da bromelina comercial, em que se observou maior estabilidade em pH 5,0 com menor perda da atividade relativa em todas as temperaturas estudadas (20, 30, 40 e 50°C). O estudo da extração da bromelina em SDFA formado por polietileno glicol (PEG) e ácido poliacrílico (PAA) (com auxílio da análise de variância de parâmetros como rendimento, fator de purificação e coeficiente de partição) proporcionou rendimento de 335% e fator de purificação de 25,8. Os hidrogéis poliméricos à base de PEG estudados apresentaram-se flexíveis, com pouca elasticidade e taxa de absorção superior a 1000%. Hidrogel carreado de bromelina pelo método de turgescência proporcionou a maior liberação da enzima, assim como a maior atividade (80% da bromelina liberada em 24 h e 278 ± 89 U/mL)

Bromelain is a collective name for the proteolytic enzymes found in the stem, fruit and leaves of pineapple (Ananas comosus Merr.). Bromelain possesses anti-inflammatory properties, debridement, among others. For bromelain production one should preferably use the waste materials, whereas pineapple fruit products have commercial application. This study aimed to extract bromelain from pineapple peels using aqueous two-phase system (ATPS), and its application in polymeric hydrogels. Stability studies of commercial bromelain were performed, which found greater stability at pH 5.0 with minor loss of relative activity at all temperatures studied. The study of bromelain extraction in ATPS composed by polyethylene glycol (PEG) and poly acrylic acid (PAA) (with assistance of variance analysis of parameters such as yield, purification factor and partition coefficient) showed yield 335% and purification factor of 25.8. The PEG-based hydrogels studied presented flexibility, low elasticity and swelling ratio higher than 1000%. Hydrogel containing bromelain, loading by embedding (solvent sorption) method, yielded the highest enzyme release, as well as the highest activity (80% bromelain released over 24 h and 278 ± 89 U / mL)

Preparation and characterisation of Dextran-70 hydrogel for controlled release of praziquantel

A hydrogel was developed from 70 kDa dextran (DEX-70) and praziquantel (PZQ) incorporated as a model drug. Biopharmaceutical properties, such as solubility and dissolution rate, were analysed in the design of the hydrogel. Furthermore, the hydrogel was also characterized by IR spectroscopy and DSC. Tests of the swelling rate showed that the hydrogel swelled slowly, albeit faster than the rate for the free polymer. In dissolution tests, the hydrogel released the drug slowly and continuously. This slow release was similar to that observed in the swelling tests and resulted in controlled release of the drug. Thus, this dextran is a suitable polymer for the development of hydrogels as vehicles for the controlled release of drugs.

Um hidrogel foi desenvolvido a partir de dextrano 70 kDa (DEX-70) e praziquantel incorporado (PZQ) como fármaco modelo. Propriedades biofarmacêuticas, como solubilidade e velocidade de dissolução, foram analisadas no desenvolvimento do hidrogel. Além disso, o hidrogel também foi caracterizado por espectroscopia na região do infravermelho e calorimetria diferencial exploratória (DSC). Testes da taxa de intumescimento mostraram que o hidrogel intumesce lentamente, embora tenha sido mais rápido do que a taxa do polímero livre. Nos testes de dissolução, o hidrogel liberou o fármaco lenta e continuamente. Esta liberação lenta foi semelhante a observada nos testes de intumescimento e resultou em uma liberação controlada do fármaco. Assim, o dextrano 70 kDa é um polímero adequado para o desenvolvimento de hidrogéis como veículos para a liberação controlada de fármacos.

Comparison of rheologic properties between Ca-alginate hydrogel microspheres suspension and whole blood / 生物医学工程学杂志

Starting from the form of red blood cells and the hematocrit (Hct, about 45 vol% of whole blood), we tried to prepare a kind of microspheres suspension to imitate non-Newtonian fluid property of whole blood, exploring its potentiality to be applied in blood viscosity quality control substance. In our study, we produced Ca-alginate hydrogel microspheres using emulsion polymerization, then we suspended the microspheres in 0.9 wt% NaCl solution to obtain a kind of liquid sample with the microspheres taking 45% volume. Then we used two types of viscometers to measure and analyse the changes of sample viscosity at different shear rate. We observed the forms of Ca-alginate hydrogel microspheres with microscope, and found them to be relatively complete, and their diameters to be normally distributed. Diameters of about 90% of the microspheres were distributed in a range from 6 to 22 micron. The samples were examined with viscometer FASCO-3010 and LG-R-80c respectively, both of which have shown a shear-thinning effect. After 5-week stability test, the CV of viscosity results corresponding to the two instruments were 7.3% to 13.8% and 8.9% to 14.2%, respectively. Although some differences existed among the results under the same shear rate, the general variation trends of the corresponding results were consistent, so the sample had the potentiality to be widely used in calibrating a different type of blood viscometer.