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Rat Adipose Tissue-Derived Stem Cells Transplantation Attenuates Cardiac Dysfunction Post Infarction and Biopolymers Enhance Cell Retention

DANOVIZ, Maria E.; NAKAMUTA, Juliana S.; MARQUES, Fabio L. N.; SANTOS, Leonardo dos; ALVARENGA, Erica C.; SANTOS, Alexandra A. dos; ANTONIO, Ednei L.; SCHETTERT, Isolmar T.; TUCCI, Paulo J.; KRIEGER, Jose E.
Fonte: PUBLIC LIBRARY SCIENCE Publicador: PUBLIC LIBRARY SCIENCE
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Background: Cardiac cell transplantation is compromised by low cell retention and poor graft viability. Here, the effects of co-injecting adipose tissue-derived stem cells (ASCs) with biopolymers on cell cardiac retention, ventricular morphometry and performance were evaluated in a rat model of myocardial infarction (MI). Methodology/Principal Findings: (99m)Tc-labeled ASCs (1 x 10(6) cells) isolated from isogenic Lewis rats were injected 24 hours post-MI using fibrin a, collagen (ASC/C), or culture medium (ASC/M) as vehicle, and cell body distribution was assessed 24 hours later by gamma-emission counting of harvested organs. ASC/F and ASC/C groups retained significantly more cells in the myocardium than ASC/M (13.8+/-2.0 and 26.8+/-2.4% vs. 4.8+/-0.7%, respectively). Then, morphometric and direct cardiac functional parameters were evaluated 4 weeks post-MI cell injection. Left ventricle (LV) perimeter and percentage of interstitial collagen in the spare myocardium were significantly attenuated in all ASC-treated groups compared to the non-treated (NT) and control groups (culture medium, fibrin, or collagen alone). Direct hemodynamic assessment under pharmacological stress showed that stroke volume (SV) and left ventricle end-diastolic pressure were preserved in ASC-treated groups regardless of the vehicle used to deliver ASCs. Stroke work (SW)...

Emprego de matriz polimérica biodegradável em dispositivos vaginais para liberação sustentada de progesterona em fêmeas bovinas: testes in vitro e in vivo; Use of biodegradable polymeric matrix, in vaginal devices, to sustained progesterone release in cows: in vitro e in vivo tests

Pimentel, José Rodrigo Valim
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/06/2006 PT
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Com o aumento do número de animais inseminados por IATF (inseminação artificial em tempo fixo), a diminuição de custos e o incremento de índices reprodutivos têm sido os objetivos de vários grupos de pesquisa. Nos protocolos de IATF utilizados, empregam-se dispositivos de liberação sustentada de progesterona (P4), que são, em sua maioria, constituídos de um esqueleto de nylon, recoberto com uma camada de silicone com P4 . Visando a diminuição dos custos de produção e impacto ambiental, foi desenvolvido um dispositivo à base de biopolímeros. Neste estudo, foram comparados dispositivos confeccionados com uma blenda constituída de Poli-hidroxi-butirato (PHB) e Poli-&epsion;-caprolactona (PCL), com o Dispositivo Interno Bovino (DIB®), utilizado como controle . No teste in vitro, utilizaram-se dois tipos de dispositivo à base de biopolímeros, com uma área superficial de 147 cm2: DISP8 (46% PHB, 46% PCL e 8% P4; n=4), DISP10 (45% PHB, 45% PCL, 10% P4; n=4) e o DIB® (1 g de P4, área de 120 cm2; n=3). Os testes in vitro foram conduzidos segundo especificações da USP 23, em um dissolutor de comprimidos, empregando-se uma mistura de álcool/água (60/40) como meio de difusão. Amostras do meio foram colhidas aos 2 min....

Properties of films obtained from biopolymers of different origins for skin lesions therapy

Bellini, Márcia Zilioli; Oliva Neto, Pedro de; Moraes, Ângela Maria
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: 289-299
ENG
Relevância na Pesquisa
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Fundação de Amparo à Pesquisa no Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); In this study, the effects of the origin of xanthan used, in combination with chitosan, to prepare films for the treatment of skin lesions were evaluated. The characteristics of the films obtained with xanthan commercially available for the food industry sector and xanthan originated from a fermentation process conducted in a pilot plant were compared. Results showed that the source did not strongly interfere in many of the properties of the films, such as the mechanical properties, cytotoxicity to L929 cells, absorption of simulated body fluid and culture medium, stability in water and saline solution. Hence, even though the properties of biopolymers of different sources might vary, the films prepared with two distinct types of xanthan gum could be considered as potentially safe and similar in terms of relevant characteristics considering the aimed application.

Formação, estrutura e propriedades reologicas de sistemas biopolimericos.; Formation, structure and rheological properties of biopolymers systems.

Ana Luiza Mattos Braga
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 24/03/2006 PT
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A utilização de diversos biopolímeros é uma prática comum nas indústrias de alimentos, especialmente em produtos lácticos, embutidos e a base de soja. O objetivo geral deste trabalho foi estudar as interações entre proteínas e polissacarídeos em sistemas contendo, ou não, co-soluto, em solução aquosa (pH 7,0) ou géis acidificados. Dentre as proteínas e os polissacarídeos utilizados na indústria de alimentos, foram estudados mais profundamente a goma xantana, o caseinato de sódio e o isolado protéico de soja (tanto em solução quanto em géis). Os polissacarídeos jataí (LBG), gelana, Na-alginato e k-carragena foram estudados apenas em soluções. As interações entre os componentes foram estudadas 1) por microscopias confocal, de força atômica e de contraste de fases e rheo-SALS ("small angle light scattering"); 2) por reologia a baixas e altas deformações, em cisalhamento ou compressão; 3) por análises químicas para determinar o tipo de força das interações. Os estudos sobre as propriedades físicas de soluções puras de biopolímeros mostraram que soluções de proteína seguem um comportamento Newtoniano, enquanto que os polissacarídeos apresentam comportamento Newtoniano a baixa concentração e pseudoplástico com o aumento desta. O tratamento térmico de soluções de xantana bem como a adição de sacarose reduziram a elasticidade da solução...

Produção de nanoestruturas de biopolímeros através de deposição "Layer-by-Layer" com propriedades antibacterianas e de imobilização de linfócitos; Production of biopolymer nanostructures through layer-by-layer deposition with antibacterial and lymphocyte immobilization properties

Fernando da Cruz Vasconcellos
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/05/2011 PT
Relevância na Pesquisa
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O trabalho trata da produção de filmes nanoestruturados multicamadas de biopolímeros sobre substratos sólidos com a técnica de deposição layer-by-layer (LbL). A técnica de montagem layer-by-layer é uma ferramenta adequada para produção controlada de filmes de multicamadas com propriedades importantes tais como: a biocompatibilidade, a biodegrabilidade, a baixa toxicidade, a hidrofilicidade e a baixa citotoxicidade, concedendo a estes filmes grande versalitidade em suas aplicações. O foco principal da pesquisa foi estudar multicamadas dos polieletrólitos naturais quitosana e ácido hialurônico e sua aplicabilidade para: 1) promover a adesão de linfócitos B, 2) gerar superfícies antibacterianas. Os testes da preparação e o estudo da variação de parâmetros de montagem de filmes dos biopolímeros, assim como sua caracterização foram úteis para a avaliação dessas aplicações. O estudo também incluiu a produção de filmes multicamadas contendo outros biopolímeros (alginato de sódio e carboximetilcelulose), assim como polímeros sintéticos e nanopartículas. A caracterização dos filmes envolveu diversas técnicas de análise, dentre elas: microscopia de força atômica (MFA), que permitiu obter informações sobre a topologia e elasticidade dos filmes...

Effect of the Injection moulding processing conditions on biopolymers final properties

Teixeira, Pedro; Pontes, A. J.; Henriques, Elsa
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2011 ENG
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This research work intended to study the effect of the main injection moulding parameters in the final properties of biopolymers mouldings. An experimental procedure was carried out in which four biopolymers containing different composition percentages of poly-lactic acid (PLA) and plasticized starch (PLS) were compared with polypropylene (PP). For each material the effect of the processing conditions (mould temperature, injection temperature and holding pressure) on the final properties was discussed and the possibility of using biopolymers as a substitute of PP in household utility products was evaluated.

Development of bioplastics from agro-wastes

Macedo, Maria João; Moura, I.; Oliveira, M.; Machado, A. V.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 22/06/2015 ENG
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During centuries synthetic polymers have been used in a variety of applications in the everyday of human life. They became essential due to its versatility, durability and low cost [1]. However, due to their excessive use, several drawbacks as its resistance to the decomposition, toxicity after incineration and accumulation in the environment induce negative ecological impact in landfills and water contamination [2]. Moreover, plastics production implies the use of non-renewable resources, such as, oil and natural gas that represents about 8 % of global consumption [1,2]. Therefore, become crucial to search for new ecological materials toward innovative and cost-effective fabrication of environmentally degradable plastics demonstrating similar performance to conventional ones [1,3]. Simultaneously, the high amount of agro-wastes generated from food industry have been a growing concern, around 1.3 billion tons are leftover, which became an environmental and financial issue [1]. Among these agro-waste stands out, food waste, halum and stems of vegetables/fruits, grains and seeds, from which it is possible to obtain natural polymers [3]. Biopolymers exhibit unique properties and can be produced from plants and crops wastes. Rubber...

Fiber functionalization for biomedical applications

Mano, Maria Francisca Amaral Gomes Marques
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Dissertação de Mestrado
Publicado em /11/2014 ENG
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Deep-eutectic solvents (DES) are considered novel renewable and biodegradable solvents, with a cheap and easy synthesis, without waste production. Later it was discovered a new subclass of DES that even can be biocompatible, since their synthesis uses primary metabolites such as amino acids, organic acids and sugars, from organisms. This subclass was named natural deep-eutectic solvents (NADES). Due to their properties it was tried to study the interaction between these solvents and biopolymers, in order to produce functionalized fibers for biomedical applications. In this way, fibers were produced by using the electrospinning technique. However, it was first necessary to study some physical properties of NADES, as well as the influence of water in their properties. It has been concluded that the water has a high influence on NADES properties, which can be seen on the results obtained from the rheology and viscosity studies. The fluid dynamics had changed, as well as the viscosity. Afterwards, it was tested the viability of using a starch blend. First it was tested the dissolution of these biopolymers into NADES, in order to study the viability of their application in electrospinning. However the results obtained were not satisfactory...

Production of biopolymers by Pseudomonas aeruginosa isolated from marine source

Jamil,Nazia; Ahmed,Nuzhat
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2008 EN
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Two bacterial strains, Pseudomonas aeruginosa CMG607w and CMG1421 produce commercially important biopolymers. CMG607w isolated from the sediments of Lyari outfall to Arabian Sea synthesize the mcl-polyhydroxyalkanoates from various carbon sources. The production of PHAs was directly proportional to the incubation periods. Other strain CMG1421, a dry soil isolate, produced high viscous water absorbing extracellular acidic polysaccharide when it was grown aerobically in the minimal medium containing glucose or fructose or sucrose as sole source of carbon. The biopolymer had the ability to absorb water 400 times more than its dry weight. This property was superior to that of currently used non-degradable synthetic water absorbents. It acted as salt filter and had rheological and stabilizing activity as well.

Properties of films obtained from biopolymers of different origins for skin lesions therapy

Bellini,Márcia Zilioli; Oliva-Neto,Pedro de; Moraes,Ângela Maria
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2015 EN
Relevância na Pesquisa
36.982805%
In this study, the effects of the origin of xanthan used, in combination with chitosan, to prepare films for the treatment of skin lesions were evaluated. The characteristics of the films obtained with xanthan commercially available for the food industry sector and xanthan originated from a fermentation process conducted in a pilot plant were compared. Results showed that the source did not strongly interfere in many of the properties of the films, such as the mechanical properties, cytotoxicity to L929 cells, absorption of simulated body fluid and culture medium, stability in water and saline solution. Hence, even though the properties of biopolymers of different sources might vary, the films prepared with two distinct types of xanthan gum could be considered as potentially safe and similar in terms of relevant characteristics considering the aimed application.

Measuring distances within unfolded biopolymers using fluorescence resonance energy transfer: The effect of polymer chain dynamics on the observed fluorescence resonance energy transfer efficiency

Makarov, Dmitrii E.; Plaxco, Kevin W.
Fonte: American Institute of Physics Publicador: American Institute of Physics
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.982805%
Recent years have seen a number of investigations in which distances within unfolded proteins, polypeptides, and other biopolymers are probed via fluorescence resonance energy transfer, a method that relies on the strong distance dependence of energy transfer between a pair of dyes attached to the molecule of interest. In order to interpret the results of such experiments it is commonly assumed that intramolecular diffusion is negligible during the excited state lifetime. Here we explore the conditions under which this “frozen chain” approximation fails, leading to significantly underestimated donor-acceptor distances, and describe a means of correcting for polymer dynamics in order to estimate these distances more accurately.

Force spectroscopy of complex biopolymers with heterogeneous elasticity

Valdman, David; Lopez, Benjamin J.; Valentine, Megan T.; Atzberger, Paul J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
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Cellular biopolymers can exhibit significant compositional heterogeneities as a result of the non-uniform binding of associated proteins, the formation of microstructural defects during filament assembly, or the imperfect bundling of filaments into composite structures of variable diameter. These can lead to significant variations in the local mechanical properties of biopolymers along their length. Existing spectral analysis methods assume filament homogeneity and therefore report only a single average stiffness for the entire filament. However, understanding how local effects modulate biopolymer mechanics in a spatially resolved manner is essential to understanding how binding and bundling proteins regulate biopolymer stiffness and function in cellular contexts. Here, we present a new method to determine the spatially varying material properties of individual complex biopolymers from the observation of passive thermal fluctuations of the filament conformation. We develop new statistical mechanics-based approaches for heterogeneous filaments that estimate local bending elasticities as a function of the filament arc-length. We validate this methodology using simulated polymers with known stiffness distributions, and find excellent agreement between derived and expected values. We then determine the bending elasticity of microtubule filaments of variable composition generated by repeated rounds of tubulin polymerization using either GTP or GMPCPP...

Biological Effects of Spirulina (Arthrospira) Biopolymers and Biomass in the Development of Nanostructured Scaffolds

de Morais, Michele Greque; Vaz, Bruna da Silva; de Morais, Etiele Greque; Costa, Jorge Alberto Vieira
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
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Spirulina is produced from pure cultures of the photosynthetic prokaryotic cyanobacteria Arthrospira. For many years research centers throughout the world have studied its application in various scientific fields, especially in foods and medicine. The biomass produced from Spirulina cultivation contains a variety of biocompounds, including biopeptides, biopolymers, carbohydrates, essential fatty acids, minerals, oligoelements, and sterols. Some of these compounds are bioactive and have anti-inflammatory, antibacterial, antioxidant, and antifungal properties. These compounds can be used in tissue engineering, the interdisciplinary field that combines techniques from cell science, engineering, and materials science and which has grown in importance over the past few decades. Spirulina biomass can be used to produce polyhydroxyalkanoates (PHAs), biopolymers that can substitute synthetic polymers in the construction of engineered extracellular matrices (scaffolds) for use in tissue cultures or bioactive molecule construction. This review describes the development of nanostructured scaffolds based on biopolymers extracted from microalgae and biomass from Spirulina production. These scaffolds have the potential to encourage cell growth while reducing the risk of organ or tissue rejection.

Chemical Modeling of Acid-Base Properties of Soluble Biopolymers Derived from Municipal Waste Treatment Materials

Tabasso, Silvia; Berto, Silvia; Rosato, Roberta; Tafur Marinos, Janeth Alicia; Ginepro, Marco; Zelano, Vincenzo; Daniele, Pier Giuseppe; Montoneri, Enzo
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 04/02/2015 EN
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This work reports a study of the proton-binding capacity of biopolymers obtained from different materials supplied by a municipal biowaste treatment plant located in Northern Italy. One material was the anaerobic fermentation digestate of the urban wastes organic humid fraction. The others were the compost of home and public gardening residues and the compost of the mix of the above residues, digestate and sewage sludge. These materials were hydrolyzed under alkaline conditions to yield the biopolymers by saponification. The biopolymers were characterized by 13C NMR spectroscopy, elemental analysis and potentiometric titration. The titration data were elaborated to attain chemical models for interpretation of the proton-binding capacity of the biopolymers obtaining the acidic sites concentrations and their protonation constants. The results obtained with the models and by NMR spectroscopy were elaborated together in order to better characterize the nature of the macromolecules. The chemical nature of the biopolymers was found dependent upon the nature of the sourcing materials.

Introduction of Soft X-Ray Spectromicroscopy as an Advanced Technique for Plant Biopolymers Research

Karunakaran, Chithra; Christensen, Colleen R.; Gaillard, Cedric; Lahlali, Rachid; Blair, Lisa M.; Perumal, Vijayan; Miller, Shea S.; Hitchcock, Adam P.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 26/03/2015 EN
Relevância na Pesquisa
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Soft X-ray absorption spectroscopy coupled with nano-scale microscopy has been widely used in material science, environmental science, and physical sciences. In this work, the advantages of soft X-ray absorption spectromicroscopy for plant biopolymer research were demonstrated by determining the chemical sensitivity of the technique to identify common plant biopolymers and to map the distributions of biopolymers in plant samples. The chemical sensitivity of soft X-ray spectroscopy to study biopolymers was determined by recording the spectra of common plant biopolymers using soft X-ray and Fourier Transform mid Infrared (FT-IR) spectroscopy techniques. The soft X-ray spectra of lignin, cellulose, and polygalacturonic acid have distinct spectral features. However, there were no distinct differences between cellulose and hemicellulose spectra. Mid infrared spectra of all biopolymers were unique and there were differences between the spectra of water soluble and insoluble xylans. The advantage of nano-scale spatial resolution exploited using soft X-ray spectromicroscopy for plant biopolymer research was demonstrated by mapping plant cell wall biopolymers in a lentil stem section and compared with the FT-IR spectromicroscopy data from the same sample. The soft X-ray spectromicroscopy enables mapping of biopolymers at the sub-cellular (~30 nm) resolution whereas...

POLYMERIC SUBSTANCES AND MICROBIAL COMMUNITIES IN SOURCE WATER AND IN BIOFILTRATION PROCESSES IN THE TREATMENT FOR DRINKING WATER

Guo, XINHAI
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
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The application of membrane filtration for drinking water treatment is limited by membrane fouling due to the accumulation of biopolymers. Biofiltration may be an effective pretreatment approach to reduce the biopolymers, thus improving the performance of membrane filtration. Biological treatment with the microbial community associated with drinking water treatment systems can potentially play a positive role on chemical contaminant removal and biopolymer reduction through biodegradation. However, extracellular polymeric substances (EPS) developed inside biofilters through microbial secretions may have adverse effects on downstream membrane filtration if an EPS sloughing event occurs. In this study, the efficacy of biofiltration to remove biopolymers was investigated. Methods developed for the analyses of EPS associated with microbial flocs and biofilms in wastewater were adapted to analyze surface waters where biopolymers are typically found at lower concentrations. Freeze-drying was found to be an effective method for concentrating water samples and to recover and analyze neutral and acidic polysaccharides (PS), but was ineffective for protein (PN) quantification. EPS extracted from the biofilter media was analyzed as part of the characterization of the microbial community associated with biofiltration. Results of water samples suggest that a passive biofilter was not effective for PS removal at the Peterborough drinking water pilot plant (DWPP). However...

Superficial distribution of aromatic compounds and geomicrobiology of sediments from Suruí Mangrove, Guanabara Bay, RJ, Brazil

Fontana,Luiz F.; Silva,Frederico S. da; Figueiredo,Natália G. de; Brum,Daniel M.; Netto,Annibal D. Pereira; Gigueiredo Junior,Alberto G. de; Crapez,Mirian A.C.
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 EN
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The distribution of selected aromatic compounds and microbiology were assessed in superficial sediments from Suruí Mangrove, Guanabara Bay. Samples were collected at 23 stations, and particle size, organic matter, aromatic compounds, microbiology activity, biopolymers, and topography were determined. The concentration of aromatic compounds was distributed in patches over the entire mangrove, and their highest total concentration was determinated in the mangrove's central area. Particle size differed from most mangroves in that Suruí Mangrove has chernies on the edges and in front of the mangrove, and sand across the whole surface, which hampers the relationship between particle size and hydrocarbons. An average @ 10% p/p of organic matter was obtained, and biopolymers presented high concentrations, especially in the central and back areas of the mangrove. The biopolymers were distributed in high concentrations. The presence of fine sediments is an important factor in hydrocarbon accumulation. With high concentration of organic matter and biopolymers, and the topography with chernies and roots protecting the mangrove, calmer areas are created with the deposition of material transported by wave action. Compared to global distributions...

Biomedical Biopolymers, their Origin and Evolution in Biomedical Sciences: A Systematic Review

Yadav, Preeti; Yadav, Harsh; Shah, Veena Gowri; Shah, Gaurav; Dhaka, Gaurav
Fonte: JCDR Research and Publications (P) Limited Publicador: JCDR Research and Publications (P) Limited
Tipo: Artigo de Revista Científica
EN
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Biopolymers provide a plethora of applications in the pharmaceutical and medical applications. A material that can be used for biomedical applications like wound healing, drug delivery and tissue engineering should possess certain properties like biocompatibility, biodegradation to non-toxic products, low antigenicity, high bio-activity, processability to complicated shapes with appropriate porosity, ability to support cell growth and proliferation and appropriate mechanical properties, as well as maintaining mechanical strength. This paper reviews biodegradable biopolymers focusing on their potential in biomedical applications. Biopolymers most commonly used and most abundantly available have been described with focus on the properties relevant to biomedical importance.

Estabilidad de enzimas en medios de distinta movilidad molecular. Impacto de interacciones con azúcares y biopolímeros y de la encapsulación; Enzyme stability in systems of different molecular mobility. Impact of interactions with sugars and biopolymers and encapsulation

Santagapita, Patricio Román
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2010 SPA
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El objetivo del presente trabajo fue analizar la estabilidad enzimática en medios de distinta movilidad molecular y las interacciones intermoleculares específicas que la favorecen. Se estudió el efecto de azúcares (trehalosa), sales y biopolímeros modificados con β-ciclodextrinas (CD) sobre las propiedades fisicoquímicas de la matriz y sobre la actividad enzimática. Se analizó también el uso de un dendrímero basado en polietilenglicol funcionalizado con CD como excipiente de matrices continuas, y se estudió la influencia de la confinación en cápsulas de polielectrolitos sobre la estabilidad enzimática y su liberación. Las enzimas utilizadas como sistemas modelo (lactasa, catalasa e invertasa) son de importancia biotecnológica. La estabilidad enzimática se analizó en distintas condiciones de humedad y temperatura de almacenamiento, en relación con la temperatura de transición vítrea y el estado físicoquímico de la matriz. La presencia de electrolitos afectó la cinética de varios fenómenos de relajación en los sistemas de trehalosa. El retraso de la cristalización de trehalosa con sales debe realizarse con mucha precaución ya que una vez que ésta cristaliza, la enzima permanece en un medio amorfo enriquecido en sales...

Study of Sorption Equilibrium of Biopolymers Alginic Acid and Xanthan with C.I. Disperse Yellow 54

Lozano-Álvarez,Juan Antonio; Jáuregui-Rincón,Juan; Mendoza-Díaz,Guillermo; Rodríguez-Vázquez,Refugio; Frausto-Reyes,Claudio
Fonte: Sociedad Química de México A.C. Publicador: Sociedad Química de México A.C.
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2009 EN
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Disperse yellow 54 (DY54) was adsorbed onto two biopolymers, alginic acid and xanthan. The adsorption isotherms for the biopolymer-DY54 system showed that the adsorption mechanism can best be described by Zimm-Bragg theory. UV-Visible, FT-IR and MicroRaman studies suggest that DY54 is bounded to both biopolymers alginic acid and xanthan through hydrogen bonding. Keto group of dye and hydroxyl groups of sugar residues from two polysaccharides were the principal functional groups involved in sorption mechanism.