Navegando por Palavras-chave "biopolymers"

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    Avaliação da função coclear e resposta tecidual da mucosa da cavidade timpânica de cobaia, quando receptora de implante biodegradável
    (Universidade Federal de São Paulo (UNIFESP), 2014-10-29) Garcia, Leandro de Borborema [UNIFESP]; Testa, Jose Ricardo Gurgel Testa [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Introduction:Treatment of cochlear disorders represents a promisingfuture in otology. Local drug delivery has distinct advantages for the treatmentof the inner ear disease. The developmentof prolonged drug delivery system, by biopolymers, may mean significant progress,once they are able to keep drug concentrations on the desired site within therapeutical levels for a long period of time. Objective: To evaluate the cochlear function and tissue response of the mucosa of the tympanic cavity of guinea pigs, when receiving biodegradable implant.Methods: A total of 20 male guinea pigs were divided into 2 groups. After paracentesis in both ears, a biodegradable polymer of poly lactic-co-glycolic acid was implanted in only one middle ear. Histological analysis using neutrophil exudate and vascular neoformation (acute inflammation) and fibroblast proliferation and mononuclear inflammatory cells (chronic inflammation) as parameters was performed after 10 and 30 days of survival (groups 1 and 2, respectively). The Brain Stem Auditory Evoked Potentials was made in all ears justbefore the implantation of the biopolymer and the euthanasia. Results:Four ears in group 1 and 7 in group 2 had an increase of neutrophil exudate. Vascular neoformation occurred in ears with or without the implant, in both groups. Fibroblast proliferation and mononuclear inflammatory cells (lymphocytes and macrophages) increased in ears with implant in group 2. None of the groups showed sensorineural hearing loss. Conclusion:The cochlear function and tissue response by histological analysis of the mucosa of the tympanic cavity of guinea pigs, when receiving biodegradable implant, showed no statistically significant difference between ears with or without the implant.
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    The effect of andiroba oil and chitosan concentration on the physical properties of chitosan emulsion film
    (Assoc Brasil Polimeros, 2016) Kimura, Vanessa Tiemi [UNIFESP]; Miyasato, Cintia Satiyo [UNIFESP]; Genesi, Bianca Pereira [UNIFESP]; Lopes, Patricia Santos [UNIFESP]; Pedroso Yoshida, Cristiana Maria [UNIFESP]; da Silva, Classius Ferreira [UNIFESP]
    Chitosan film is used as a dressing to heal burns. The physical and biological properties of the film can be modified by the addition of phytotherapic compounds. This work used the casting -solvent evaporation technique to prepare chitosan film containing andiroba oil (Carapa guianensis) which has anti-inflammatory, antibiotic, and healing properties. The objective of this study was to determine the effect of the concentrations of chitosan and andiroba oil on the physical properties of chitosan films. The emulsion films were evaluated concerning the mechanical properties and fluid handling capacity. Additionally, scanning electron microscopy and thermal analysis were performed. The results showed that the barrier and mechanical properties were affected by the addition of andiroba oil, and these may be modulated as a function of the concentration of oil added to the film. The thermal analysis showed no evidence of chemical interactions between the oil and chitosan.
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    Phase Behaviour and Miscibility Studies of Collagen/Silk Fibroin Macromolecular System in Dilute Solutions and Solid State
    (Mdpi, 2017) Ghaeli, Ima; de Moraes, Mariana A. [UNIFESP]; Beppu, Marisa M.; Lewandowska, Katarzyna; Sionkowska, Alina; Ferreira-da-Silva, Frederico; Ferraz, Maria P.; Monteiro, Fernando J.
    Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pairs through the detection of phase separation and improvement of the mechanical and physical properties of the blend. This study presents the formulation of a stable and one-phase mixture of collagen and regenerated silk fibroin (RSF), with the highest miscibility ratio between these two macromolecules, through inducing electrostatic interactions, using salt ions. For this aim, a ternary phase diagram was experimentally built for the mixtures, based on observations of phase behavior of blend solutions with various ratios. The miscibility behavior of the blend solutions in the miscible zones of the phase diagram was confirmed quantitatively by viscosimetric measurements. Assessing the effects of biopolymer mixing ratio and salt ions, before and after dialysis of blend solutions, revealed the importance of ion-specific interactions in the formation of coacervate-based materials containing collagen and RSF blends that can be used in pharmaceutical, drug delivery, and biomedical applications. Moreover, the conformational change of silk fibroin from random coil to beta sheet, in solution and in the final solid films, was detected by circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR), respectively. Scanning electron microscopy (SEM) exhibited alterations of surface morphology for the biocomposite films with different ratios. Surface contact angle measurement illustrated different hydrophobic properties for the blended film surfaces. Differential scanning calorimetry (DSC) showed that the formation of the beta sheet structure of silk fibroin enhances the thermal stability of the final blend films. Therefore, the novel method presented in this study resulted in the formation of biocomposite films whose physico-chemical properties can be tuned by silk fibroin conformational changes by applying different component mixing ratios.