Effect of Chitosan Biopolymer on Microbial Decay in Tomato (Solanum lycopersicum L.) Variety ‘Dev’ under Ambient Temperature

The current study sought to investigate the influence of chitosan biopolymer against microbial decay in tomato. In the present study, bulk-chitosan at different concentrations (0.01, 0.04, 0.08, 0.12, 0.16, 0.20% w/v) along with control were evaluated on tomato variety ?Dev? by dipping fruits for 6 min and stored at ambient temperature (27ºC±2). Bulk-chitosan at 0.16% was found most effective to prevent microbial decay and maintain sensory evaluation from day 1 to days 21 as compared to control. Based on the aforementioned results and comparative evaluation of different doses of bulk-chitosan, we concluded that chitosan is very effective at less concentration and thus exert minimum chemical load on the treated tomatoes. Therefore, it may claim that chitosan biopolymer have potential to protects tomato against microbial decay.

Uso de quitina e quitosana como adsorventes de amônia de efluentes aquícolas: revisão de literatura / Use of chitin and quitosan as adsorvents of ammonia of aquaculture effluents: a literature review / Uso de quitina y quitosana como adsorbentes de amonia de efluentes acuícolas: revisión de literatura

Os resíduos provenientes da aquicultura são derivados da ração e da excreção dos peixes e podem estar sedimentados, suspensos ou dissolvidos, ocasionando elevados valores de DBO, DQO, nitrogênio e fósforo. A produção de camarões no Brasil tem gerado elevadas quantidades de resíduos sólidos, tendo em vista que os exoesqueletos dos camarões correspondem a cerca de 40% do seu peso total, resultando num forte impacto ambiental. Diversas pesquisas envolvendo a quitina estão sendo desenvolvidas na área de tratamento de água, devido principalmente a sua capacidade de formar filme, sendo utilizada em sistemas filtrantes. Este polissacarídeo também pode ser utilizado como agente floculante no tratamento de efluentes, como adsorvente na clarificação de óleos, e principalmente na produção de quitosana. Atualmente a quitosana possui aplicações multidimensionais, desde áreas como a nutrição humana, biotecnologia, ciência dos materiais, indústria farmacêutica, agricultura, terapia genética e proteção ambiental. A quitosana é muito eficiente na remoção de poluentes em diferentes concentrações. Apresenta alta capacidade e grande velocidade de adsorção, boa eficiência e seletividade tanto em soluções que possuem altas ou baixas concentrações. O uso da biotecnologia, através do processo de adsorção utilizando adsorventes naturais e baratos, como a quitina e quitosana, minimiza os impactos ambientais da aquicultura tanto em relação aos provocados pelo lançamento de efluentes no meio ambiente quanto aos causados pelo descarte inadequado dos resíduos do processamento de camarões.(AU)

Aquaculture residues are derived from fish feed and excretion and may be sedimented, suspended or dissolved, resulting in high BOD, COD, nitrogen and phosphorus values. Shrimp production in Brazil has generated high amounts of solid waste, since shrimp exoskeletons account for about 40% of their total weight, resulting in a strong environmental impact. Several researches involving chitin are being developed in the area of water treatment, mainly due to its ability to form film, being used in filter systems. This polysaccharide can also be used as a flocculating agent in the treatment of effluents, as an adsorbent in the clarification of oils, and especially in the production of chitosan. Currently, chitosan has multidimensional applications, from areas such as human nutrition, biotechnology, materials science, pharmaceutical industry, agriculture, gene therapy and environmental protection. Chitosan is very efficient in the removal of pollutants at different concentrations. It presents high capacity and high adsorption velocity, good efficiency and selectivity both in solutions that have high or low concentrations. The use of biotechnology, through the adsorption process using natural and cheap adsorbents such as chitin and chitosan, minimizes the environmental impacts of aquaculture both in relation to those caused by the release of effluents into the environment and those caused by the inappropriate disposal of processing residues of shrimps.(AU)

Los residuos procedentes de la acuicultura se derivan de la ración y de la excreción de los peces y pueden estar sedimentados, suspendidos o disueltos, ocasionando elevados valores de DBO, DQO, nitrógeno y fósforo. La producción de camarones en Brasil ha generado grandes cantidades de residuos sólidos, teniendo en cuenta que los exoesqueletos de los camarones corresponden a cerca del 40% de su peso total, resultando en un fuerte impacto ambiental. Varias investigaciones involucrando la quitina se están desarrollando en el área de tratamiento de agua, debido principalmente a su capacidad de formar película, siendo utilizada en sistemas filtrantes. Este polisacárido también puede ser utilizado como agente floculante en el tratamiento de efluentes, como adsorbente en la clarificación de aceites, y principalmente en la producción de quitosana. Actualmente la quitosana posee aplicaciones multidimensionales, desde áreas como la nutrición humana, biotecnología, ciencia de los materiales, industria farmacéutica, agricultura, terapia genética y protección ambiental. La quitosana es muy eficiente en la eliminación de contaminantes en diferentes concentraciones. Presenta alta capacidad y gran velocidad de adsorción, buena eficiencia y selectividad tanto en soluciones que poseen altas o bajas concentraciones. El uso de la biotecnología, a través del proceso de adsorción utilizando adsorbentes naturales y baratos, como la quitina y quitosana, minimiza los impactos ambientales de la acuicultura tanto en relación a los provocados por el lanzamiento de efluentes en el medio ambiente en cuanto a los causados por el descarte inadecuado de los residuos del procesamiento de camarones.(AU)

Preparação e caracterização de nanocarreadores de beta-lactose à base de pectina e lisozima / Preparation and characterization of beta-lactose nanocarriers based on pectin and lysozyme

O objetivo deste trabalho foi preparar e caracterizar nanocarreadores via auto-organização a partir da pectina de citros e lisozima para o encapsulamento da ß-lactose. Foram estudadas três condições de interação entre os biopolímeros variando a razão molar pectina/lisozima (3:1, 2:1, 1:1, 1:2 e 1:3), o pH e o tempo de aquecimento. A confirmação da interação foi determinada por espectroscopia no infravermelho por transformada de Fourier (FTIR) e por calorimetria de varredura diferencial (DSC). Os espectros de infravermelho evidenciaram que ligações de hidrogênio foram as principais forças envolvidas na formação dos nanocarreadores e sugeriram a ausência de ß-lactose livre na superfície das nanopartículas. Os termogramas evidenciaram que as nanopartículas formadas na presença de ß-lactose têm maior estabilidade térmica do que as nanopartículas sem ß-lactose. Para ambas as formulações estudadas, na presença e na ausência de ß-lactose, a formação das nanopartículas ocorreu entre os valores de pKa e ponto isoelétrico (pI) da pectina e lisozima, respectivamente, sendo a melhor razão de interação pectina/lisozima 1:2, em pH 10, a 80 ºC por 30 min. As nanopartículas foram formadas via auto-organização e todos as partículas apresentaram distribuição de tamanho homogênea, formato esférico, diâmetro inferior a 100 nm e carga superficial negativa. A morfologia e o tamanho das partículas pouco alteraram com a incorporação da -lactose. A eficiência de encapsulação (EE) da ß-lactose foi superior a 96% para as concentrações estudadas. Ensaios preliminares in vitro, em células epiteliais de câncer de cólon (HCT-116), evidenciaram que as nanopartículas formadas são capazes de adentrar no meio intracelular, possivelmente, por via endocitose

This work aimed to prepare and characterize nanocarriers via self-assembly using citrus pectin and lysozyme for ß-lactose encapsulation. Three interaction conditions between the biopolymers were studied, varying the pectin/lysozyme molar ratio (3:1, 2:1, 1:1, 1:2 and 1:3), pH and heating time. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) determined the interaction's confirmation. The infrared spectra showed that hydrogen bonds were the main forces involved in the formation of nanocarriers and suggested the absence of free ß-lactose on the surface of the nanoparticles. The thermograms showed that nanoparticles formed in the presence of ß-lactose have greater thermal stability than nanoparticles without ß-lactose. For both formulations studied, in the presence and absence of lactose, the formation of nanoparticles occurred between the pKa and isoelectric point (pI) values of pectin and lysozyme, respectively, with the best pectin/lysozyme interaction molar ratio 1:2, at pH 10, at 80 °C for 30 min. Nanoparticles were formed via self-assembly, and all particles presented homogeneous size distribution, spherical shape, diameter less than 100 nm, and negative surface charge. The morphology and size of the particles changed little with the incorporation of ß-lactose. The encapsulation efficiency (EE) of ß-lactose was higher than 96% for the concentrations studied. Preliminary in vitro assays in colon cancer epithelial cells (HCT-116) showed that the nanoparticles formed are capable of entering the intracellular medium, possibly via endocytosis

Evaluation of eggshell membrane as an alternative biopolymeric matrix for delivery of nimesulide / Avaliação da membrana da casca do ovo como uma matriz biopolimérica alternativa para entrega de nimesulida / Evaluación de la membrana de la cáscara de huevo como una matriz de biopolímero alternativa para la administración de nimesulida

SUMMARY Introduction: Eggshell membrane (ESM) is a tissue found between the eggshell and the albumen of eggs that has attractive properties for use in drug delivery systems. Aim: To incorporate in ESM and used it as a model drug in release studies. The color change and FTIR analysis of the biopolymer proved the incorporation of nimesulide in ESM. Results: The drug uptake was 176.83 and 122.69 mg g-1 by natural and cross-linked ESM. Release studies were carried out using a spectrophotometric flow system in simulated intestinal fluid pH 7.4. The release profiles showed that after 60 minutes 54.55 and 42.58 % of the drug were released from natural and cross-linked ESM, respectively. Kinetics parameters indicated that drug release was better described by the Higuchi model and through a non-Fickian release. Conclusion: Considering these results is proved that ESM has the potential to become a polymeric matrix for drug release systems.

RESUMO Introdução: a membrana da casca do ovo (MCO) é um tecido encontrado entre a casca e o albúmen de ovos que possui propriedades atrativas para uso em sistemas de liberação de fármacos. Objetivo: incorporar à MCO e utilizá-la como fármaco modelo em estudos de liberação. Mudança de coloração e análises de FTIR do biopolímero comprovaram a incorporação da nimesulida na MCO. A incorporação do fármaco foi de 176,83 e 122,69 mg g-1 na MCO natural e reticulada, respectivamente. Resultados: os estudos de liberação foram realizados usando um sistema de fluxo espectrofotométrico em fluido intestinal simulado pH 7,4. Os perfis de liberação mostraram que após 60 minutos 54,55 e 42,58 % do medicamento foram liberados da MCO natural e reticulada, respectivamente. Os parâmetros cinéticos indicaram que a liberação do fármaco foi mais bem descrita pelo modelo de Higuchi e por meio de uma liberação não Fickiana. Conclusão: considerando estes resultados, fica comprovado que a MCO tem potencial para se tornar uma matriz polimérica para sistemas de liberação de fármacos.

RESUMEN Introducción: La membrana de cáscara de huevo (MCH) es un tejido que se encuentra entre la cáscara de huevo y la albúmina de los huevos que tiene propiedades atractivas para su uso en sistemas de administración de fármacos. Objetivo: Incorporar en MCH y utilizarla como fármaco modelo en estudios de liberación. El cambio de color y el análisis FTIR del biopolímero demostraron la incorporación de nimesulida en MCH. Resultados: La captación del fármaco fue de 176,83 y 122,69 mg g-1 por MCH natural y reticulado. Los estudios de liberación se llevaron a cabo utilizando un sistema de flujo espectrofotométrico en líquido intestinal simulado pH 7,4. Los perfiles de liberación mostraron que después de 60 minutos el 54,55 y el 42,58 % del fármaco se liberó de la MCH natural y reticulada, respectivamente. Los parámetros cinéticos indicaron que la liberación del fármaco se describió mejor mediante el modelo de Higuchi y mediante una liberación no Fickian. Conclusión: De acuerdo con estos resultados, el MCH tiene el potencial de convertirse en una matriz polimérica para sistemas de liberación de fármacos.

Exopolysaccharyde production by Cryptococcus laurentii SD7 using molasses and corn steep liquor as substrates / Exopolysaccharyde production by Cryptococcus laurentii SD7 using molasses and corn steep liquor as substrates

Microbial polysaccharides are of great biotechnological and commercial interest and have wide application in the food, cosmetic and medicine industries. Exopolysaccharide (EPS) production by the yeast Cryptococcus laurentii SD7, isolated from fresh water molluscs, was studied using agro-industrial byproducts as substrates in the submerged fermentation. The Central Composite Design (CCD) 23 was used to study the influence of pH, different concentrations on sugarcane molasses and corn steep liquor (CSL), for 48 hours. According to the results, the highest EPS production occurred at the initial pH 5 and at 8.4% concentration of sugarcane molasses, which were statistically significant variable at 10% (p < 0.1). The concentration of CSL had no influence in the studied range, thus, it can be used lowest concentration (0.3%). The time course of EPS production showed that while cell growth peaked within 48 hours, the highest EPS production (6.61 g L-1) occurred at 168 hours, with a productivity of about 0.04 g L-1 h-1. The pH of the medium remained approximately constant throughout the fermentation process. The yeast C. laurentii SD7 showed great potential for EPS production at a low cost and with sustainable substrates.

Microbial polysaccharides are of great biotechnological and commercial interest and have wide application in the food, cosmetic and medicine industries. Exopolysaccharide (EPS) production by the yeast Cryptococcus laurentii SD7, isolated from fresh water molluscs, was studied using agro-industrial byproducts as substrates in the submerged fermentation. The Central Composite Design (CCD) 23 was used to study the influence of pH, different concentrations on sugarcane molasses and corn steep liquor (CSL), for 48 hours. According to the results, the highest EPS production occurred at the initial pH 5 and at 8.4% concentration of sugarcane molasses, which were statistically significant variable at 10% (p < 0.1). The concentration of CSL had no influence in the studied range, thus, it can be used lowest concentration (0.3%). The time course of EPS production showed that while cell growth peaked within 48 hours, the highest EPS production (6.61 g L-1) occurred at 168 hours, with a productivity of about 0.04 g L-1 h-1. The pH of the medium remained approximately constant throughout the fermentation process. The yeast C. laurentii SD7 showed great potential for EPS production at a low cost and with sustainable substrates.

Improvement of polyhydroxybutyrate production by deletion of csrA in Escherichia coli

BACKGROUND: Poly-3-hydroxybutyrate (PHB) can be efficiently produced in recombinant Escherichia coli by the overexpression of an operon (NphaCAB) encoding PHB synthetase. Strain improvement is considered to be one of critical factors to lower the production cost of PHB in recombinant system. In this study, one of key regulators that affect the cell growth and PHB content was confirmed and analyzed. RESULT: S17-3, a mutant E. coli strain derived from S17-1, was found to be able to achieve high cell density when expressing NphaCAB with the plasmid pBhya-CAB. Whole genome sequencing of S17-3 revealed genetic alternations on the upstream regions of csrA, encoding a global regulator cross-talking between stress response, catabolite repression and other metabolic activities. Deletion of csrA or expression of mutant csrA resulted in improved cell density and PHB content. CONCLUSION: The impact of gene deletion of csrA was determined, dysfunction of the regulators improved the cell density of recombinant E. coli and PHB production, however, the detail mechanism needs to be further clarified.

Development And Evaluation Of Novel Bionanoparticles Loaded With Nanosized Lamotrigine By Using The Novel Isolated Biopolymer From Phaseolus Vulgaris Seeds

The aim of this research was to isolate and characterize the novel biopolymer from Phaseolus vulgaris seeds and to formulate lamotrigine loaded bionanoparticles using this biomaterial. The biopolymer was isolated by simplified and economical process and analysed for different physico-chemical and spectral properties. The nanosizing of lamotrigine was done by bath sonication method and its particle size in nano-range was screened by UV method. The bionanosuspension loaded with nanosized lamotrigine was prepared by bath sonication for 15 cycles (1cycle equal to 3 minutes). The formulated bionanosuspension loaded with lamotrigine using biopolymer was compared with lamotrigine loaded bionanosuspension by using HPMC. The bionanosuspension was subjected for pH study, dispersibility study, % entrapment efficiency, nanosizing screening, particle size study and in vitro study for drug release and stability study of formulated bionanosuspension. The best formulation LPVu7 showed up to 90.36 ±0.9% drug release in 36 hours. having t 50% of 17 hours and t80% of 29 hours with r2 value of 0.9927 as compared to release from LSP5 with 92.43±0.68% having t 50% of 16 hours and t80% of 28 hours with r2 value of 0.9951 in 36 hours. The results reveal that isolated biopolymer may be used as an alternative to synthetic polymer because of its novel inbuilt bioretardant cum biostabilizing properties. The formulated bionanosuspension are feasible for delivering the nanosized lamotrigine in sustained manner for prolonged time for long term treatment of epilepsy.

Xanthan gum production by Xanthomonas axonopodis pv. mangiferaeindicae from glycerin of biodiesel in different media and addition of glucose

Biodiesel production has been increasing yearly in Brazil. A large amount of glycerin is generated in this process and needs a correct destination. One possible use of this glycerin in crude form is in biotechnological processes. Xanthan gum is a commercial gum used primarily in the pharmaceutical and food industries as thickener, emulsifier and stabilizer. It is synthetized by species of the bacterium Xanthomonas generally from glucose. However, current research shows that species of this bacterium have the capacity to grow and synthesize the gum using glycerin from biodiesel. The aim of this study was to produce xanthan gum using glycerin from biodiesel production in medium with different nitrogen content, named complex and simple media. The kinetics of fermentation in simple medium showed a twofold increase in gum production (3.16 kg.m-3) compared to the one in complex medium (1.46 kg.m-3) after 120 hours. The gum generated in this study showed chemical and rheological characteristics of xanthan gum. Glucose supplementation did not show an increase in xanthan production but did increase the consistency index and the behavioral index of solutions of this gum.

Fibrin biopolymer as scaffold candidate to treat bone defects in rats

Bone tissue repair remains a challenge in tissue engineering. Currently, new materials are being applied and often integrated with live cells and biological scaffolds. The fibrin biopolymer (FBP) proposed in this study has hemostatic, sealant, adhesive, scaffolding and drug-delivery properties. The regenerative potential of an association of FBP, biphasic calcium phosphate (BCP) and mesenchymal stem cells (MSCs) was evaluated in defects of rat femurs. Methods: Adult male Wistar rats were submitted to a 5-mm defect in the femur. This was filled with the following materials and/or associations: BPC; FBP and BCP; FBP and MSCs; and BCP, FBP and MSCs. Bone defect without filling was defined as the control group. Thirty and sixty days after the procedure, animals were euthanatized and subjected to computed tomography, scanning electron microscopy and qualitative and quantitative histological analysis. Results: It was shown that FBP is a suitable scaffold for bone defects due to the formation of a stable clot that facilitates the handling and optimizes the surgical procedures, allowing also cell adhesion and proliferation. The association between the materials was biocompatible. Progressive deposition of bone matrix was higher in the group treated with FBP and MSCs. Differentiation of mesenchymal stem cells into osteogenic lineage was not necessary to stimulate bone formation. Conclusions: FBP proved to be an excellent scaffold candidate for bone repair therapies due to application ease and biocompatibility with synthetic calcium-based materials. The satisfactory results obtained by the association of FBP with MSCs may provide a more effective and less costly new approach for bone tissue engineering.(AU)

Uso de la ecografía de alta resolución de tejidos blandos para la caracterización de material exógeno y sus complicaciones / High Resolution Ultrasound of Soft Tissues for Characterization of Fillers and its Complications

Introducción: El ultrasonido de alta resolución ha demostrado ser un método diagnóstico útil para la detección de material exógeno, su caracterización y evaluación de sus complicaciones. Este trabajo es una serie de casos de 60 pacientes, recolectados en un periodo de tres años. Es un estudio retrospectivo, descriptivo. Objetivos: Describir las localizaciones más frecuentes del material exógeno en las zonas del cuerpo afectadas. Describir el tipo de material exógeno más utilizado y su aspecto ecográfico. Establecer las complicaciones más frecuentes. Métodos: Se realizó ecografía de alta resolución por parte de una radióloga con ocho años de entrenamiento en ecografía dermatológica. Los estudios se realizaron en un equipo Toshiba Xario 200 con transductor lineal de 18 MHz. Para el análisis estadístico se emplearon medidas de tendencia central, descripción de frecuencias y cruce de variables. Resultados: La edad promedio de los pacientes fue 55 años y el 90,5 % fueron mujeres. La zona más afectada fueron los surcos nasogenianos, donde se encontró material exógeno en el 85,7 % de los pacientes. La sustancia encontrada más comúnmente fueron los biopolímeros (39 %), la silicona líquida y el aceite tuvieron, respectivamente, el 32,5 % y 15,6 %. En el 67,2 % de los casos se encontró deformidad física en los pacientes, manifestada como masa palpable o visible. Conclusión: La ecografía permitió identificar los diferentes tipos de sustancias exógenas, su ubicación en la zona anatómica específica y las complicaciones relacionadas con su uso, lo cual suministró información útil al médico tratante e impactó en el manejo de los pacientes.

Introduction: High resolution ultrasound has proven to be a useful diagnostic method for the detection of exogenous material, its characterization and evaluation of its complications. This study is a series of cases of 60 patients collected in a period of 3 years. It is a retrospective, descriptive study. Objectives: To describe the most frequent locations of the exogenous material in the affected areas of the body. To describe the type of exogenous material most used and its ultrasound appearance. To establish the most frequent complications. Methods: High resolution ultrasound was performed by a radiologist with eight years of training in dermatological ultrasound. The studies were carried out in a Toshiba Xario 200 device with an 18 MHz lineal transductor. For the statistical analysis, measures of central tendency, description of frequencies and crossing of variables were used. Results: the average age of the patients was 55 years, 90.5% of the patients were women. The most affected area were the nasolabial folds where exogenous material was found in 85.7% of the patients. The substance most commonly found was biopolymers in 39%; liquid silicone and oil had respectively 32.5% and 15.6%. In 67.2% of the cases the patients presented physical deformity manifested as a palpable or visible mass. Conclusion: The ultrasound allowed us to identify the different types of exogenous substances, their location in the specific anatomical area and the complications related to their use, providing useful information to the attending physician and impacting the management of the patients.

Sugarcane biopolymer as a guide tube in the regeneration of peripheral nerves in rats / Biopolímero de caña de azúcar como tubo guía en la regeneración de nervios periféricos en ratones

SUMMARY: Peripheral nerve regeneration is a serious clinical problem. The goal of this work was to evaluate comparatively a biopolymer tube of sugarcane with an expanded polyethylene tube as a tube guide in peripheral nerve regeneration. Fourteen male albino Wistar rats were used, separated into three different groups: control (CG), lesion + polyethylene tube (PG) and lesion + sugarcane biopolymer (SBG). At 60 days old, animals from the PG and SBG underwent surgery for tubulization of the sciatic nerve, and 60 days after the injury they were sacrificed for collection of the nerve. In the analysis of the number of nerve fibers, a smaller number was seen in the PG and SBG groups compared to the CG, no difference was seen between the PG and SBG groups (p<0.05). With regard to the number of blood vessels, the SBG group had a larger number than the CG and PG groups (p<0.05). The SBG also presented increase on axonal diameter and G -ratio compared to PG (p<0.05). Taken together these data revealed that biopolymer tube favors a suitable environment for peripheral nerve regeneration.

RESUMEN: La regeneración nerviosa periférica es un problema clínico grave. El objetivo de este trabajo fue evaluar comparativamente un tubo de biopolímero de caña de azúcar con un tubo de polietileno expandido, como guía de tubo en la regeneración de nervios periféricos. Se utilizaron dieciocho ratas Wistar albinas macho, separadas en tres grupos: control (CG), lesión + tubo de polietileno (PG) y lesión + biopolímero de caña de azúcar (SBG). A los 60 días de edad, los animales del PG y SBG fueron sometidos a una cirugía para la tubulización del nervio ciático, y 60 días después de la lesión fueron sacrificados para la recolección del nervio. En el análisis del número de fibras nerviosas, se observó un número menor en los grupos PG y SBG en comparación con el CG; no se observaron diferencias entre los grupos PG y SBG (p <0,05). Con respecto al número de vasos sanguíneos, el grupo SBG tuvo un número mayor que los grupos CG y PG (p <0,05). El SBG también presentó un aumento en el diámetro axonal y la proporción G en comparación con PG (p <0,05). En conjunto, estos datos revelaron que el tubo de biopolímero favorece un entorno adecuado para la regeneración de nervios periféricos.

Estudio de la capacidad de absorción en hidrogeles semi-interpenetrados de poliacrilamida/poli(hidroxibu tirato-co-hidroxivalirato) / Study of the absorption capacity in semi-interpenetrating hydrogels of polyacrylamide/poly(hydro xybutyrate-co-hydroxy valerate) / Estudo da capacidade de absorção em hidrogéis semi-interpenetrados de poliacrila mida/poli(hidroxibutirato-co-hidroxivalerato)

Resumen Se sintetizaron hidrogeles semi-interpenetrados (semi-IPN) obtenidos a partir de acrilamida (AAm) y el biopolímero poli(hidroxibutirato-co-hidroxivalerato) (P(HB-co-HV)) de diferente masa molar (Mv). El análisis de la estructura química de los materiales se realizó mediante espectroscopia FT-IR. Los resultados sugirieron la incorporación del P(HB-co-HV) dentro de la red entrecruzada de la poliacrilamida (PAAm), lo que indicó que el hidrogel semi-IPN fue sintetizado. Adicionalmente, se analizaron muestras del gel seco semi-IPN a través de calorimetría diferencial de barrido. Se siguió gravimétricamente el comportamiento de hinchamiento de los hidrogeles en agua y se analizó el efecto de la composición porcentual y del porcentaje de reactivo entrecruzante (N,N'-metilenbisacrilamida, MBAAm) sobre los mecanismos de transporte de agua. Los resultados obtenidos indicaron que los hidrogeles semi-IPN se hinchan menos que el hidrogel de PAAm pura, lo que se atribuyó al carácter hidrófobo del biopolímero incorporado dentro de la red entrecruzada del material. Se calculó el exponente de difusión de los hidrogeles (n) y en todos los casos se obtuvo que n < 0,50. Por tanto, el proceso de difusión es menos Fickiano, lo que significa que la rapidez de penetración del agua es mucho menor que la velocidad de relajación de las cadenas de polímero.

Abstract Semi-interpenetrated hydrogels (semi-IPN) obtained from acrylamide (AAm) and the biopolymer poly(hydroxybutyrate-co-hydroxyvalerate) (P(HB-co-HV)) of different molar mass (Mv) were synthesized. Chemical structure of the synthesized materials was analyzed by using FT-IR spectroscopy. The results suggested the incorporation of P(HB-co-HV) within the cross-linked network of the Polyacrylamide (PAAm), which indicated that the semi-IPN hydrogel was synthesized. To confirm this result, semi-IPN dry gel samples were analyzed by differential scanning calorimetry. The swelling behavior of the hydrogels in water was followed gravimetrically and the effect of the percentage composition and percentage of crosslinking reagent (N,N'-methylenebisacrylamide, MBAAm) on the water transport mechanisms was analyzed. Results indicated that the semi-IPN hydrogels swell less than the PAAm hydrogel alone, which was attributed to the hydrophobic nature of the biopolymer incorporated within the crosslinked network of the material. Additionally, the diffusion exponent of the hydrogels (n) was calculated and in all cases, the obtained result was n < 0.50. This fact shows that the diffusion process is less Fickian, which means that the speed of water penetration is lower than the speed of relaxation of the polymer chain.

Resumo Foram sintetizados hidrogéis semi-interpenetrados (semi-IPN) obtidos a partir de acrilamida (AAm) e biopolímero poli(hidroxibutirato-co-hidroxivalerato) (P(HB-co-HV)) de diferente peso molecular (Mv). Os resultados da análise da estrutura química do material foram feitos por espectroscopia FT-IR. Os resultados sugerem à adição do P(HB-co-HV) no interior da rede de ligações cruzadas de poliacrilamida (PAAm), isto indica que o hidrogel semi-IPN foi sintetizado. Este resultado foi confirmado, por meio da análise de amostras de calorimetria diferencial de varredura do gel seco semi-IPN. O comportamento do inchamento dos hidrogéis na água foi seguido pela gravimetria e foi analisado o efeito da composição percentual e a percentagem de reagente de ligação cruzada (N,N'-metilenobisacrilamida, MBAAm) sobre o mecanismo de transporte de água. Os resultados indicam que os hidrogéis semi-IPN incham-se menos do que o hidrogel da PAAm pura. Este comportamento foi atribuído ao carácter hidrofóbico incorporado no material do biopolímero incorporado dentro da rede de ligações cruzadas. O expoente de difusão dos hidrogéis (n) foi calculado, e em todos os casos foi obtido que n < 0,50. Então o processo de difusão é menos Fickiano, o que significa que a velocidade de penetração da água é muito mais baixa do que a taxa de relaxamento da cadeia de polímero.

EFFICACY OF NATURAL BIOPOLYMER CHITOSAN MEMBRANE FOR GUIDED TISSUE REGENERATION / Шинэ санаа Шинэ нээлт

@#BACKGROUND. Periodontal regeneration is the reconstruction of periodontal tissues and restoration of functions, which is achieved through techniques, such as soft tissue grafts, guided tissue regeneration, bone replacement grafts, root bio-modification, and a combination of these techniques. Chitosan is a natural biopolymer with several beneficial properties, including excellent biocompatibility, low toxicity and corresponding degradation rates and hemostatic activities. This systematic review assessed the efficacy of biopolymer membrane (chitosan) for guided tissue regeneration (GTR) in animal and human studies. MATERIAL AND METHODS. The Cochrane Oral Health Group specialist trials, PubMed, MEDLINE, and EMBASE databases were searched for articles published before January 2017. Animal and human studies that used chitosan for GTR, which had a follow-up period of ≥6 weeks and 6 months, respectively, were retrieved. The following outcomes were analyzed: new bone (NB) and new cementum (NC) formation for animal studies and probing pocket depth and clinical attachment level changes for human studies. RESULTS. After a full-text review,six animal studies and three human studies were found to be eligible for this study. All included animal and human studies demonstrated that the use of chitosan for GTR exerts a positive effect on periodontal defects. Subgrouping meta-analysis outcomes of three dog studies revealed that GTR with pure chitosan membranes has a positive effect on NB (14.36%) and NC (10.21%) formation. CONCLUSION. Within the limitations of the present study, there is little evidence to demonstrate the efficacy of chitosan for GTR either in animal or human studies. Chitosan should rather be used as an adjunct component for membrane production.

Leucaena leucocephala (Lam.) de Wit., “subabul” stem lignin: Isolation, structural characterization and thermal properties.

Lignin is the second most abundant renewable biopolymer on earth after cellulose. It is being used in many industrial applications due to its abundance. In the present study, lignin was isolated from the stems of Leucaena leucocephala (Lam.) de Wit., a high biomass yielding plant using acidic dioxane under N2 atmosphere. Structural characterization of isolated dioxane lignin (DL) was performed by analytical techniques: UV, FT-IR, 1H NMR and 13C NMR. Their monolignol content was determined by nitrobenzene oxidation followed by HPLC-MS/MS analysis. The data was compared with commercial alkali lignin (AL). The results showed that DL is of hardwood guaiacyl-syringyl (GS) type, whereas AL is softwood type with more guaiacyl units and trace amounts of p-hydroxyphenyl units (H). Thermogravimetric analysis (TGA) of DL showed two stage thermal degradation profile similar to AL. The DTGmax for DL and AL were found in the second major loss event of second stage of TGA at 424°C and 404°C, respectively. Differential scanning calorimetry (DSC) study exhibited the glass transition temperatures (Tg) at 132°C and 122°C for DL and AL, respectively. The results from thermal stability studies suggest that dioxane lignin isolated from the "miracle tree" (subabul) can be exploited in various thermoplastic industrial applications.

Production and characterization of polyhydroxybutyrate (PHB) produced by Bacillus sp. isolated from Egypt.

Synthetic polymers are non-degradable and accumulated in the environment so, the efforts of scientists were forwarded to provide us with alternative environmentally biopolymers. Polyhydroxyalkanoates (PHAs) including polyhydroxybutyrate (PHB) are Group of the interesting biopolymers which have several medical applications such as drug delivery, suture, scaffold and heart valves. PHAs are biological macromolecules, thermoplastics, biodegradable and biocompatible. In this study, new bacterial isolates from Egypt were screened for their ability to produce PHB using Nile red dye. Out of 44 isolates, 19 bacterial isolates were selected according to strong of their fluorescence on mineral salt medium (MSM) agar plates supplemented with Nile red. The most potent strain was identified using biochemical tests as Bacillus sp. N-2. Production of PHB was carried out in limitation of nitrogen source using a minimal salt medium (MSM) supplemented with an excess of glucose as sole carbon source. PHB was accumulated in relation to cell dry weight about 20% (PHB/CDW). The obtained biopolymer was purified and analyzed using NMR, FT-IR, TGA and DSC thus; it was highly pure and identified as PHB. Optimization of PHB production from cheap sources appears to be a realistic goal in the future for reducing the costs and obtaining high yield.

Treatment of tympanic membrane perforation using bacterial cellulose: a randomized controlled trial / Tratamento do tímpano perfurado com enxerto de celulose bacteriana: ensaio clínico controlado e randomizado

ABSTRACT INTRODUCTION: Promising treatments for tympanic membrane perforation closure have been studied. Therapies derived from tissue engineering probably eliminate the need for conventional surgery. Bacterial cellulose is presented as an alternative that is safe, biocompatible, and has low toxicity. OBJECTIVES: To investigate the effect on healing of direct application of a bacterial cellulose graft on the tympanic membrane compared to the conventional approach with autologous fascia. METHODS: Randomized controlled trial. Forty patients with tympanic membrane perforations secondary to chronic otitis media were included, and were randomly assigned to an experimental group (20), treated with a bacterial cellulose graft (BC) and control group (20), treated with autologous temporal fascia (fascia). We evaluated the surgical time, hospital stay, time of epithelialization and the rate of tympanic perforation closure. Hospital costs were compared. The statistical significance level accepted was established at p < 0.05. RESULTS: The closure of perforations was similar in both groups. The average operation time in the fascia group was 76.50 min versus 14.06 min bacterial cellulose in the group (p = 0.0001). The hospital cost by the Brazilian public health system was R$ 600.00 for the bacterial cellulose group, and R$ 7778.00 for the fascia group (p = 0.0001). CONCLUSION: Bacterial cellulose grafts promoted the closure of the tympanic membrane perforations, and were demonstrated to be innovative, effective, safe, minimally invasive, efficacious and to have a very low cost.

RESUMO INTRODUÇÃO: Tratamentos promissores para o fechamento da perfuração da membrana timpânica vêm sendo estudados. Terapias provenientes de engenharia de tecidos provavelmente eliminarão a necessidade de uma intervenção cirúrgica convencional. A celulose bacteriana apresenta-se como uma alternativa por ser segura, de baixa toxicidade, biocompatível. OBJETIVOS: Investigar o efeito da aplicação direta do enxerto da celulose bacteriana na cicatrização de perfurações da membrana timpânica, comparado ao procedimento convencional com fáscia autóloga. MÉTODO: Incluíram-se 40 pacientes com perfuração da membrana timpânica por otite média crônica simples. Randomizados de 1 a 40, onde os ímpares (20) foram tratados com enxerto de celulose bacteriana (CB), e os pares (20), com enxerto de fáscia temporal autóloga (fáscia). Estudo clínico controlado e randomizado. O tempo cirúrgico e de hospitalização foram o tempo de epitelização e custos hospitalares. RESULTADOS: O fechamento das perfurações foi semelhante nos dois grupos. O tempo médio da cirurgia no grupo fáscia foi de 76,50 minutos e de 14,06 minutos no grupo com celulose bacteriana (p = 0,0001). O custo hospitalar pela tabela do SUS foi de R$ 600,00 para o grupo CB e R$ 7.778,00 para o grupo fáscia (p = 0,0001). CONCLUSÃO: A celulose bacteriana promoveu o fechamento da perfuração do tímpano, mostrando-se inovador, seguro, eficaz, efetivo, minimamente invasivo e de baixo custo.

Evaluation of the antimicrobial activity of chitosan and its quaternized derivative on E. coli and S. aureus growth

Abstract Chitosan is largely known for its activity against a wide range of microorganisms, in which the most acceptable antimicrobial mechanism is found to include the presence of charged groups in the polymer backbone and their ionic interactions with bacteria wall constituents. This interaction suggests the occurrence of a hydrolysis of the peptidoglycans in the microorganism wall, provoking the leakage of intracellular electrolytes, leading the microorganism to death. The charges present in chitosan chains are generated by protonation of amino groups when in acid medium or they may be introduced via structural modification. This latter can be achieved by a methylation reaction resulting in a quaternized derivative with a higher polymeric charge density. Since the charges in this derivative are permanents, it is expected a most efficient antimicrobial activity. Hence, in the present study, commercial chitosan underwent quaternization processes and both (mother polymer and derivative) were evaluated, in gel form, against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative), as model bacteria. The results, as acquired from turbidity measurements, differ between materials with an expressive reduction on the Gram-positive microorganism (S. aureus) growth, while E. coli (Gram-negative) strain was less sensitive to both polymers. Additionally, the antibacterial effectiveness of chitosan was strongly dependent on the concentration, what is discussed in terms of spatial polymer conformation.

Bioconversion of mixed free fatty acids to poly-3-hydroxyalkanoates by Pseudomonas putida BET001 and modeling of its fermentation in shake flasks

Background: The paper reports on the utilization of palm kernel oil (PKO) as a low cost renewable substrate for medium-chain-length poly-3-hydroxyalkanoates (mcl-PHA) production by Pseudomonas putida BET001. Investigation on the effects of selected key variables on growth, mixed free fatty acids consumption and mcl-PHA production by the bacterial culture in the shaken flask system were carried out along with its kinetic modeling. Results: The biomass production, fatty acids consumption and mcl-PHA production were found favorable when the strain was cultured in mineral medium at pH 6-7,28°C, aeration surface-to-volume ratio of 0.4 x 10(6) m-1, 250 rpm agitation rate for 48 h. Mcl-PHA production by this strain showed mixed growth and non-growth associated components as described by Luedeking-Piret kinetic model. Conclusion: The findings of this study provided add to the literature on key variables in for achieving good microbial growth and mcl-PHA production in shake flasks culture. In addition, suitable kinetic model to describe cultivation in this system was also presented.

An experimental study of bio-polymer composite film as a micro-skin autograft covering / 实用医学杂志

Objective To explore the promoting effects of bio-polymer composite film as a micro-skin auto-graft covering on wound healing. Methods The full thickness skin defect models were made on both sides of 30 experimental rabbits. Then, the rabbits were randomly divided into experimental group and control group. In the for-mer group, the side was covered with chitosan/glucomannan composite membrane and in the latter, the side cov-ered with acelluar porcine skin after micro-skin autograft. We obtained wound tissues at week 1 , 2, 3, 4 and 5 af-ter operation. The conditions of wound healing were observed, the rate of wound healing was calculated, HE stain-ing was made, and PCNA and CD31 were detected by immunohistochemistry. Results (1) During 2~4 weeks af-ter operation, the rate of wound healing in the experimental group was significantly higher than that of the control wound (P<0.01). (2) The amount of neutrophil in experimental group was less than that of the control after oper-ation. (3) During 1 ~ 2 weeks after operation, the expression of PCNA in the experimental group was higher than that of the control group (P < 0.01), but lower than the control wounds during 1 ~ 2 weeks after operation (P <0.01). (4) During 1 ~ 5 weeks after operation, the expression of CD31 in the experimental group was higher than that of the control group (P < 0.01). Conclusion Chitosan/glucan-mannan composite membrane as a micro-skin autograft covering may promote wound healing.

Porous Microcarrier-Enabled Three-Dimensional Culture of Chondrocytes for Cartilage Engineering: A Feasibility Study

Cartilage repair is substantially intractable due to poor self-healing ability. Porous microspheres can be a fascinating three-dimensional matrix for cell culture and injectable carrier in cartilage engineering. In this study, we assessed the feasible use of porous biopolymer microspheres for chondrocyte carriers. When seeded onto the blended biopolymer microspheres and followed by a dynamic spinner flask culture, the chondrocytes showed robust growth behaviors during the culture period. The gene expressions of SOX9, type II collagen, and aggrecan were significantly upregulated after 2-week of culture. Furthermore, immunolocalization of type II collagen and secretion of glycosaminolglycan became prominent. The results suggest the feasible usefulness of the porous microspheres as the cell culture matrix and the subsequent delivery into cartilage defects.