Papers by Author: M.C. Sá Miranda

Abstract: The ability of calcium titanium phosphate (CTP) and hydroxyapatite (HAp) microspheres to reversibly adsorb the enzyme glucocerebrosidase (GCR) while preserving its biological activity, and efficiently deliver it to Gaucher disease (GD) fibroblasts was investigated. CTP microspheres adsorbed ca. 3.6-fold more GCR than HAp microspheres. The activity of adsorbed GCR was higher than the free enzyme in the case of CTP microspheres and lower when HAp was used. GCR release from both types of microspheres was characterized by the initial elution of a large percentage of enzyme followed by a delayed release that extended for at least 30 days. Released GCR was internalized by GD fibroblasts increasing their intracellular enzymatic activity. In cells treated with the same amount of GCR-loaded CTP microspheres or free-GCR a higher intracellular activity was detected in the former case, suggesting an improved efficacy.

Abstract: In this study, the addition of calcium phosphate powders to an alginate matrix was evaluated as a strategy to modulate enzyme release-kinetics from alginate microspheres and, simultaneously, to improve cell adhesion to the polymer. Pre-adsorption of the enzyme to the ceramic powders resulted in a more adequate release pattern. The ratio of ceramic-to-polymer had a pronounced effect on osteoblast adhesion to microspheres. Cells were only able to spread on microspheres with the highest percentage of ceramic (0.4 w/w using a 1.5% w/v alginate solution).