Examinando por Materia "Chitosan"

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    Determinación de los cambios en altura y densidad ósea después de un proceso de preservación con un sustituto óseo sintético.
    (2016-11-10) Henao, Sandra Lorena; Morales, Lina Mariel; Valencia, Carlos; Arce, Sandra; Jaramillo, Adriana; Cruz, Carlos; Martínez, Carlos
    Objetivo: Determinar los niveles de altura y densidad osea alcanzada en alvéolos postexodoncia, 15 dias y tres meses despues de ser injertados con un sustituto óseo experimental. Materiales y Métodos: Se distribuyeron aleatoriamente 37 alvéolos postexodoncia en dos grupos, uno experimental (n=21) y otro control (n=16). En el grupo experimental se utilizó un material compuesto por β-Fosfato tricalcico y quitosano, en el grupo control se empleó un producto comercial compuesto por una mezcla bifásica de hidroxiapatita (HA) y fosfato tricalcico (TCP). Se realizaron tomografías a los 15 días y 3 meses postquirúrgicos determinando niveles óseos (altura y anchura en la zona injertada); también se determinó la densidad ósea utilizando unidades Hounsfield. La información obtenida se procesó con la aplicación STATA versión 13. Se calcularon frecuencias para el sexo, tipo de alvéolo y tipo de injerto utilizado, y para las variables numéricas de edad, densidad ósea, altura ósea, grosor crestal, se establecieron promedios y desviación estándar. El nivel de confianza se estableció en 95% y el nivel de significancia en 5%. Resultados: Al comparar la densidad y altura ósea en los dos grupos no se encontraron diferencias estadísticamente significativas, pero si al comparar el ancho en la zona de la cresta (p<0.05). Conclusiones: El biocompuesto cerámico con quitosano mostró ser útil en preservar niveles óseos en los alvéolos postexodoncia y presentó diferencias estadísticamente significas en el ancho del reborde. Aim: Determine bone density and height reached fifteen (15) days and three (3) months after being grafted an sockets with a synthetic bone substitute and compared with experimental ceramic biocomposite. Materials and Methods: Thirty-seven sockets (37) selected randomly were grafted in clinics of the University of Valle, sixteen sockets (16) for control group and twenty (21) for the experimental group. CT scans were performed at 15 days and 3 months post-surgery determining bone levels: vertical height and width in the grafted area; bone density is also determined by analyzing Hounsfield units. The information obtained was processed with the STATA version 13 application frequencies for gender, type of socket and type of graft used, and for numeric variables of age, bone density, bone height, thickness crestal, averages were established and deviation were calculated standard. The confidence level was set at 95% and the significance level of 5%. Results: Bone density and height, no statistically significant differences between the intervention group (group 1) and control (group 2). For peak thickness statistically significant differences (p<0.05). The variation or change between start and end of follow within each group found that there is no statistically significant difference. Conclusions: The ceramic biocomposite with chitosan and graft tricalcium phosphate and hydroxyapatite no statistically significant differences in density and height in the scans at 15 and 90 days. The bone width showed statistically significant differences.
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    Determining the Relation between the Proportion of the Amino Group and the Degree of Deacetylation of Chitosan.
    (2015-09-21) Escobar Sierra, Diana Marcela; Castro Ramírez, Alex Mauricio; Vergara Castrillón, Natalia Andrea
    Several methods such as elemental analysis or infrared spectroscopy technique (IR) have been already developed to determine the degree of N-acetylation, for chitin and chitosan. This paper proposed the potentiometric technique to determine the relationship between the amino group proportion and the deacetylation degree of chitosan, using two chitosan samples obtained from different sources: one, by previously established protocols, and a commercial chitosan. The polymers tested were characterized by X-ray Diffraction and Fourier Transform Infrared Spectroscopy to verify the purity of the polymers. The proposed technique allowed us to demonstrate that the molecular weight of the synthesized chitosan are within the range reported for the biopolymer with amino group proportions similar to those obtained for samples of commercial chitosan. Resumen Varios métodos han sido desarrollados para determinar el grado de N-acetilación de la quitina y el quitosano, como el análisis elemental, o la espectroscopía de infrarrojo (IR). En este trabajo se propuso emplear el método potenciométrico para determinar la relación entre el porcentaje del grupo amino y el grado de desacetilación del quitosano, para lo cual se emplearon dos muestras de quitosano obtenido de diferentes fuentes (utilizando protocolos establecidos previamente) y un Espectroscopía de Infrarrojo con Transformada de Fourier para corroborar la pureza de los polímeros. La técnica propuesta permitió demostrar que el peso molecular de los quitosanos sintetizados se encuentra dentro de los márgenes reportados para dicho biopolímero, con una proporción del grupo amino muy similar a la obtenida para muestras de quitosano comercial.
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    Preparation and characterization of scaffold nanofibers by electrospinning, based on chitosan and fibroin from Silkworm (Bombyx mori)
    (Universidad del Valle, 2017-01-30) Cárdena Pérez, Yesica C.; Vera Graziano, Ricardo; Muñoz Prieto, Efrén d. J.; Gómez Pachón, Edwin Y.
    (Eng) Here we present a study on the preparation of scaffolding for nanofibers composed of chitosan (QS) and fibroin from cocoon silkworm (Bombyx mori) (FGS) for its potential use in biomedicine. The scaffolds conformed by nanofibers were prepared from different mixtures of QS and FGS. They were characterized with analytical techniques such as scanning electron microscopy-SEM, infrared spectroscopy-FTIR, X-ray diffraction-XRD, Thermogravimetric Analysis-TGA, Differential Scanning Calorimetry-DSC and Citocompatibility tests, to determine its morphology, functional groups, thermal transitions, and cell viability of the scaffolding QS/FGS. Nanofibers of different diameters of QS/FGS (8-177 nm) were obtained and compared with the fibers of cocoons (22-36 μm) and fibroin (7-13 μm). The best scaffolds were achieved from a physical mixture with a weight ratio QS: FGS (1:3) dissolved in trifluoroacetic acid under the following electrospinning parameters. Voltage: 20 kV, injection flow: 0.5 ml/h, needle-collector distance: 12 cm, relative humidity: 28% Temperature: 25 ° C. It was determined that the scaffolding QS/FGS possessed fibers with nanometric diameters less than 200 nm, which allow optimal cell adhesion and thermal stability at the application site, with a view to control the degradation of the scaffold. Thermal analyses, supplemented with XRD studies reveal the internal structure of the fibers. Besides Cytocompatibility test on prepared cell scaffolds, it indicates that the integrity requirement was achieved and the necessity to control the pH to achieve an increased cell viability. The results show that nanofibers QS/FGS can be a good candidate for tissue engineering in biomedical applications such as scaffolds.