RESUMO
Mineralized films are interesting biomaterials to repair bone defects. They can be easily shaped into bone defect and be permeated by body fluids as well as allow cell proliferation. Xanthan and chitosan films mineralized with hydroxyapatite prepared and characterized in this work showed an improved film stability and controlled swelling degree when dipped in different pH buffers. The layer-by-layer technique used in the film's preparation associated with the behaviour at different pH allowed to explore separately each interaction - polysaccharide-polysaccharide and polysaccharide-ions. The entanglement between polysaccharides, the interaction of the oppositely charged polysaccharides ionic groups (amine for chitosan and carboxylate for xanthan) and the interaction with Ca2+ ions confers a pH-responsive behaviour to the films. The mineralization with in situ hydroxyapatite formation resulted in an additional stability in the mineral phase. It has lower crystallinity similar to bone mineral as confirmed by X-Ray diffractogram. The films that were dipped in calcium phosphate solution during their production had positive results with in vitro cell adhesion test using MG63 cells culture.
Assuntos
Materiais Biocompatíveis/química , Quitosana/química , Durapatita/química , Polissacarídeos Bacterianos/química , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , SolubilidadeRESUMO
Glass-ceramics based on the Li2O-SiO2 system have been extensively used as restorative dental materials due to their excellent chemical durability, aesthetics, inertness in the buccal environment, and high fracture strength; but they are not bioactive. On the other hand, all known bioactive glasses show ability to bond to bone, teeth and cartilage coupled to osteoconduction and osteoinduction, but their fracture strength and toughness are rather low. The aim of this study is to develop and evaluate the in vitro biocompatibility of a new type of (bioactive and strong) lithia-silica glass-ceramic. For these purposes, two types of glass-ceramics based on a multicomponent lithia-silica system were studied: lithium metasilicate (LM) and lithium disilicate (LD). The in vitro bioactivity study was conducted in a SBF solution, before and after different times of immersion; the new materials were analyzed by XRD, FTIR, and SEM. Some samples were subjected to in vitro biodegradation tests to quantify the release of lithium and the weight loss. Cytotoxicity, adhesion, and cell proliferation on different samples were examined by using the Methyl Tetrazolium salt (MTS) and Alizarin Red. For ~40â¯vol% crystallinity, lithium metasilicate was detected as the major phase, whereas for ~80â¯vol% crystallinity, lithium disilicate was the major phase. The LD proved to be strong (3p-bending strength of 233⯱â¯12â¯MPa) and bioactive after 14â¯days of immersion in SBF. In terms of lithium ion release, the LD was outside the toxic range (>8.3â¯ppm). The LM and LD are not cytotoxic. The LD shows the best cellular adhesion and proliferation, leading to the formation of a mineralized matrix after 21â¯days. These results clearly suggest that the new LD brand is strong and highly biocompatible and warrants further study.
Assuntos
Cerâmica/farmacologia , Porcelana Dentária/farmacologia , Teste de Materiais , Animais , Apatitas/química , Varredura Diferencial de Calorimetria , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Análise do Estresse Dentário , Humanos , Camundongos Endogâmicos BALB C , Minerais/química , Difração de Raios XRESUMO
The possibility of producing valued devices from low cost natural resources is a subject of broad interest. The present study explores the preparation and characterization of silk fibroin dense membranes using waste silk fibers from textile processing. Morphology, crystallinity, thermal resistance and cytotoxicity of membranes as well as the changes on the secondary structure of silk fibroin were analyzed after undergoing treatment with ethanol. Membranes presented amorphous patterns as determined via X-ray diffraction. The secondary structure of silk fibroin on dense membranes was either random coil (silk I) or beta-sheet (silk II), before and after ethanol treatment, respectively. The sterilized membranes presented no cytotoxicity to endothelial cells during in vitro assays. This fact stresses the material potential to be used in the fabrication of biomaterials, as coatings of cardiovascular devices and as membranes for wound dressing or drug delivery systems.