Browsing by Author "Silva, Daniela"
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- Characterization of the Mechanical and Biological Properties of a New Alumina ScaffoldPublication . Batista, Patrícia Sofia Pinhanços; Rodrigues, Miguel; Silva, Daniela; Morgado, Patrícia I.; Henriques, J.; Almeida, Maria; Silva, Abílio P.; Correia, Ilídio Joaquim SobreiraPurpose: In this work, an alumina scaffold was produced through a new method to be used in a near future as a bone substitute. Methods: In vitro and in vivo studies were performed in order to characterize the mechanical and biological properties of the scaffold. Results: the results obtained showed that this scaffold has high mechanical resistance and a porous surface that allows human osteoblast cells to adhere and proliferate. the in vivo studies revealed no systemic reaction. Conclusions: the alumina scaffold produced herein has the mechanical and biological properties that are compatible with its application in bone therapy.
- Development of a new chitosan hydrogel for wound dressingPublication . Ribeiro, MP.; Espiga, Ana; Silva, Daniela; Baptista, Patrícia; Henriques, Joaquim; Ferreira, Catarina L.; Silva, Jorge; Borges, João; Pires, Eduardo; Chaves, Paula; Correia, Ilídio Joaquim SobreiraWound healing is a complex process involving an integrated response by many different cell types and growth factors in order to achieve rapid restoration of skin architecture and function. The present study evaluated the applicability of a chitosan hydrogel (CH) as a wound dressing. Scanning electron microscopy analysis was used to characterize CH morphology. Fibroblast cells isolated from rat skin were used to assess the cytotoxicity of the hydrogel. CH was able to promote cell adhesion and proliferation. Cell viability studies showed that the hydrogel and its degradation by-products are noncytotoxic. The evaluation of the applicability of CH in the treatment of dermal burns in Wistar rats was performed by induction of full-thickness transcutaneous dermal wounds. Wound healing was monitored through macroscopic and histological analysis. From macroscopic analysis, the wound beds of the animals treated with CH were considerably smaller than those of the controls. Histological analysis revealed lack of a reactive or a granulomatous inflammatory reaction in skin lesions with CH and the absence of pathological abnormalities in the organs obtained by necropsy, which supported the local and systemic histocompatibility of the biomaterial. The present results suggest that this biomaterial may aid the re-establishment of skin architecture.
- Development of a new chitosan hydrogel for wound dressingPublication . Ribeiro, MP.; Espiga, Ana; Silva, Daniela; Baptista, Patrícia; Henriques, Joaquim; Ferreira, Catarina L.; Silva, Jorge C.; Borges, João P.; Pires, Eduardo; Chaves, Paula; Correia, Ilídio Joaquim SobreiraWound healing is a complex process involving an integrated response by many different cell types and growth factors in order to achieve rapid restoration of skin architecture and function. The present study evaluated the applicability of a chitosan hydrogel (CH) as a wound dressing. Scanning electron microscopy analysis was used to characterize CH morphology. Fibroblast cells isolated from rat skin were used to assess the cytotoxicity of the hydrogel. CH was able to promote cell adhesion and proliferation. Cell viability studies showed that the hydrogel and its degradation by-products are noncytotoxic. The evaluation of the applicability of CH in the treatment of dermal burns in Wistar rats was performed by induction of full-thickness transcutaneous dermal wounds. Wound healing was monitored through macroscopic and histological analysis. From macroscopic analysis, the wound beds of the animals treated with CH were considerably smaller than those of the controls. Histological analysis revealed lack of a reactive or a granulomatous inflammatory reaction in skin lesions with CH and the absence of pathological abnormalities in the organs obtained by necropsy, which supported the local and systemic histocompatibility of the biomaterial. The present results suggest that this biomaterial may aid the re-establishment of skin architecture.
- A poly(ε-caprolactone) device for sustained release of an anti-glaucoma drugPublication . Natu, Mădălina; Gaspar, Manuel; Ribeiro, Carlos; Correia, Ilídio Joaquim Sobreira; Silva, Daniela; Sousa, Hermínio C. de; Gil, MariaImplantable dorzolamide-loaded discs were prepared by blending poly(ε-caprolactone), PCL, with poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), Lu. By blending, crystallinity, water uptake and mass loss were modified relative to the pure polymers. Burst was diminished by coating the discs with a PCL shell. All samples presented burst release except PCL-coated samples that showed controlled release during 18 days. For PCL-coated samples, barrier control of diffusion coupled with partition control from the core slowed down the release, while for 50/50 Lu/PCL-coated samples, the enhancement in the porosity of the core diminished partition control of drug release. Nonlinear regression analysis suggested that a degradation model fully describes the release curve considering a triphasic release mechanism: the instantaneous diffusion (burst), diffusion and polymer degradation stages. The MTT test indicated that the materials are not cytotoxic for corneal endothelial cells. A good in vitro–in vivo correlation was obtained, with similar amounts of drug released in vitro and in vivo. The discs decreased intraocular pressure (IOP) in normotensive rabbit eyes by 13.0% during 10 days for PCL-coated and by 13.0% during 4 days for 50/50 Lu/PCL-coated samples. The percentages of IOP decrease are similar to those obtained by dorzolamide eyedrop instillation (11.0%).