Percorrer por autor "Silva, Diana"
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- Antiseptic-loaded casein hydrogels for wound dressingsPublication . Garcia, Leonor Vasconcelos; Silva, Diana; Costa, Maria Madalena; Armés, Henrique; Salema-Oom, Madalena; Saramago, Benilde; Serro, Ana PaulaChronic wound treatment accounts for a substantial percentage of the medical expenses worldwide. Improving and developing novel wound care systems can potentially help to handle this problem. Wound dressings loaded with antiseptics may be an important tool for wound care, as they inhibit bacterial growth at the wound site. The goal of the present work was to investigate the potential of using casein hydrogel dressings loaded with two antiseptic drugs, Octiset® or polyhexanide, to treat chronic wounds. Casein-based hydrogels are inexpensive and have several properties that make them suitable for biomedical applications. Two types of casein were used: casein sodium salt and acid casein, with the formulations being labelled CS and C, respectively. The hydrogels were characterised with respect to their physical properties (swelling capacity, water content, morphology, mechanical resistance, and stability), before and after sterilisation, and they showed adequate values for the intended application. The hydrogels of both formulations were able to sustain controlled drug-release for, at least, 48 h. They were demonstrated to be non-irritant, highly haemocompatible, and non-cytotoxic, and revealed good antimicrobial properties against Staphylococcus aureus and Pseudomonas aeruginosa. Steam-heat sterilisation did not compromise the material’s properties. The in vivo performance of C hydrogel loaded with Octiset® was evaluated in a case study with a dog. The efficient recovery of the wounds confirms its potential as an alternative for wound treatment. To our knowledge, this is the first time that wound dressings loaded with Octiset®, one of the most efficient drugs for wound treatment, were prepared and tested.
- Atividades formativas e conteúdos de apoio no domínio da Ciência Aberta: a ação das bibliotecas da Universidade de AveiroPublication . Reis, Cecília; Cortês, Cristina; Silva, Diana; Vieira, Maria do Céu; Dias, SusanaA dimensão de apoio à investigação e aprendizagem das Bibliotecas de Ensino Superior (BES) é potenciada face ao contexto atual de Ciência Aberta (CA). A conceção de conteúdos e serviços de apoio à investigação requer das BES exigentes atividades de planeamento para as quais devem convergir vários fatores, como a colaboração com a comunidade, a diversificação das atividades de formação e de autoaprendizagem e a atualização constante das competências da equipa de trabalho. Vemo-nos com um papel promotor e facilitador, integrado em várias frentes colaborativas, fundamental para as atuais exigências aos investigadores, unidades de investigação e instituição no seu todo, de forma a dar resposta aos desafios e compromissos ligados à CA. As bibliotecas da Universidade de Aveiro (UA) definem as competências de literacia de informação e digitais nos domínios ligados às práticas de CA como uma área privilegiada, estabelecendo um plano de ações no apoio à comunidade.
- Book of Abstracts of 11th Iberian Conference on TribologyPublication . Serro, Ana Paula; Branco, Ana Catarina Branco; Carneiro, Carla; Silva, Diana; Guedes, M.; Figueiredo-Pina, Célio
- Chitosan/alginate based multilayers to control drug release fromophthalmic lensPublication . Silva, Diana; Pinto, Luís F. V.; Bozukova, Dimitriya; Santos, Luís F.; Serro, Ana Paula; Saramago, BenildeIn this study we investigated the possibility of using layer-by-layer deposition, based in natural polymers (chitosan and alginate), to control the release of different ophthalmic drugs from three types of lens materials: a silicone-based hydrogel recently proposed by our group as drug releasing soft contact lens (SCL) material and two commercially available materials: CI26Y for intraocular lens (IOLs) and Definitive 50 for SCLs. The optimised coating, consisting in one double layer of (alginate – CaCl2)/(chitosan + glyoxal) topped with a final alginate-CaCl2 layer to avoid chitosan degradation by tear fluid proteins, proved to have excellent features to control the release of the anti-inflammatory, diclofenac, while keeping or improving the physical properties of the lenses. The coating leads to a controlled release of diclofenac from SCL and IOL materials for, at least, one week. Due to its high hydrophilicity (water contact angle ≈ 0) and biocompatibility, it should avoid the use of further surface treatments to enhance the useŕs comfort. However, the barrier effect of this coating is specific for diclofenac, giving evidence to the need of optimizing the chemical composition of the layers in view of the desired drug.
- Controlled drug delivery from ophthalmic lensesPublication . Topete, Ana; Oliveira, Andreia; Pimenta, Andreia; Silva, Diana; Carrilho, Magda; Paradiso, Patrizia; Kumar, Prashneel; Galante, Raquel; Mata, José; Colaço, Rogério; Saramago, Benilde; Serro, Ana Paula
- Development of polycarbonate urethane-based materials with controlled diclofenac release for cartilage replacementPublication . Oliveira, Andreia S.; Ferreira, Inês; Branco, Ana C.; Silva, João C.; Costa, Carolina; Nolasco, Pedro; Marques, Ana C.; Silva, Diana; Colaço, Rogério; Figueiredo-Pina, Célio; Serro, Ana P.ydrogels are very promising human cartilage replacement materials since they are able to mimic its structure and properties. Besides, they can be used as platforms for drug delivery to reduce inflammatory postsurgical reactions. Polycarbonate urethane (PCU) has been used in orthopedic applications due to its long-term biocompatibility and bio-durability. In this work, PCU-based hydrogels with the ability to release an anti-inflammatory (diclofenac) were developed, for the first time, for such purpose. The materials were reinforced with different amounts of cellulose acetate (CA, 10%, 15%, and 25% w/w) or carbon nanotubes (CNT, 1% and 2% w/w) in order to improve their mechanical properties. Samples were characterized in terms of compressive and tensile mechanical behavior. It was found that 15% CA and 2% CNT reinforcement led to the best mechanical properties. Thus, these materials were further character- ized in terms of morphology, wettability, and friction coefficient (CoF). Contrarily to CNTs, the addition of CA significantly increased the material's porosity. Both mate- rials became more hydrophilic, and the CoF slightly increased for PCU + 15%CA. The materials were loaded by soaking with diclofenac, and drug release experiments were conducted. PCU, PCU + 15%CA and PCU + 2%CNT presented similar release pro- files, being able to ensure a controlled release of DFN for at least 4 days. Finally, in vitro cytotoxicity tests using human chondrocytes were also performed and con- firmed a high biocompatibility for the three studied materials.
- Diclofenac release from a silicon based contact lens material controlled by a chitosan/alginate coatingPublication . Filipe, Helena; Silva, Diana; Pinto, Luís F. V.; Henriques, José; Bozukova, Dimitriya; Saramago, Benilde; Serro, Ana Paula
- Effect of varying functional monomers in experimental self-adhesive composites : polymerization kinetics, cell metabolism influence and sealing abilityPublication . Ferreira, Marta Nunes; Santos, Marta Neves Dos; Fernandes, Inês; Marto, Carlos Miguel; Laranjo, Mafalda; Silva, Diana; Serro, Ana Paula; Carrilho, Eunice; Botelho, Maria Filomena; Azul, Ana Mano; Delgado, António H. S.The aim was to evaluate the effects of adding different functional monomers to experimental self-adhesive composites (SACs) on polymerization kinetics, cell metabolic activity, and sealing ability. SACs were formulated using urethane dimethacrylate as the base monomer and triethylene glycol dimethacrylate. Additionally, 10 wt.% of distinct functional monomers were added - 10-methacryloyloxydecyl dihydrogen phosphate, glycerol phosphate dimethacrylate (GPDM), 2-hydroxyethyl methacrylate (HEMA) or hydroxyethyl acrylamide (HEAA). ATR-FTIR was used to determine real-time polymerization kinetics (20 min, n = 3). The final extrapolated conversion and polymerization rates were determined (DC,max;Rp,max). The DC,max values were employed to calculate volumetric shrinkage. The MTT assay was performed on MDPC-23 cells using disc extracts at different concentrations (n = 8). Class V cavities were prepared in 60 sound human molars, assigned to six groups (n = 10), depending on the composite used and aging type (T0 or TC, if thermocycled for 10 000 cycles). One-way ANOVA, two-way, and Kruskal–Wallis tests were employed to treat the data (ɑ = 0.05). Varying the functional monomers had a large impact on DC,max, as confirmed by one-way ANOVA (p<0.001). The highest was obtained for HEMA (64 ± 3%). The HEMA and HEAA formulations were found to be significantly more toxic at concentrations below 100%. For microleakage, having a functional monomer or not did not show any improvement, irrespective of margin or aging period (Mann–Whitney U, p > 0.05). Larger functional monomers MDP and GPDM affected polymerization properties. Conversely, their acidity did not seem to be detrimental to cell metabolic activity. Regarding sealing ability, it seems that the functional monomers did not bring an advantage to the composites. Varying the functional monomer in SACs had a clear impact on the polymerization kinetics as well as on their cytotoxic potential. However, it did not confer better microleakage and sealing. Claiming self-adhesiveness based only on functional monomers seems dubious.
- Effects of Non-Conventional Sterilisation Methods on PBO-Reinforced PVA Hydrogels for Cartilage ReplacementPublication . Pires, Tomás; Oliveira, Andreia Sofia; Marques, Ana Clara; Salema-Oom, Madalena; Figueiredo-Pina, Célio; Silva, Diana; Serro, Ana PaulaArticular cartilage (AC) degradation is a recurrent pathology that affects millions of people worldwide. Polyvinyl alcohol (PVA) hydrogels have been widely explored for AC replacement. How- ever, their mechanical performance is generally inadequate, and these materials need to be reinforced. Moreover, to be used in a clinical setting, such materials must undergo effective sterilisation. In this work, a PVA hydrogel reinforced with poly(p-phenylene-2,6-benzobisoxazole) (PBO) nanofibres was submitted to three non-conventional sterilisation methods: microwave (MW), high hydrostatic pressure (HHP), and plasma (PM), in order to evaluate their impact on the properties of the material. Sterilisation was achieved in all cases. Properties such as water content and hydrophilicity were not affected. FTIR analysis indicated some changes in crystallinity and/or crosslinking in all cases. MW was revealed to be the most suitable method, since, unlike to PM and HHP, it led to a general improvement of the materials’ properties: increasing the hardness, stiffness (both in tensile and compression), and shear modulus, and also leading to a decrease in the coefficient of friction against porcine cartilage. Furthermore, the samples remained non-irritant and non-cytotoxic. Moreover, this method allows terminal sterilisation in a short time (3 min) and using accessible equipment.
- Effects of non-conventional sterilisation methods on PBO-reinforced PVA hydrogels for cartilage replacementPublication . Pires, Tomás; Oliveira, Andreia Sofia; Marques, Ana Clara; Salema-Oom, Madalena; Figueiredo-Pina, Célio G.; Silva, Diana; Serro, Ana PaulaArticular cartilage (AC) degradation is a recurrent pathology that affects millions of people worldwide. Polyvinyl alcohol (PVA) hydrogels have been widely explored for AC replacement. However, their mechanical performance is generally inadequate, and these materials need to be reinforced. Moreover, to be used in a clinical setting, such materials must undergo effective sterilisation. In this work, a PVA hydrogel reinforced with poly(p-phenylene-2,6-benzobisoxazole) (PBO) nanofibres was submitted to three non-conventional sterilisation methods: microwave (MW), high hydrostatic pressure (HHP), and plasma (PM), in order to evaluate their impact on the properties of the material. Sterilisation was achieved in all cases. Properties such as water content and hydrophilicity were not affected. FTIR analysis indicated some changes in crystallinity and/or crosslinking in all cases. MW was revealed to be the most suitable method, since, unlike to PM and HHP, it led to a general improvement of the materials’ properties: increasing the hardness, stiffness (both in tensile and compression), and shear modulus, and also leading to a decrease in the coefficient of friction against porcine cartilage. Furthermore, the samples remained non-irritant and non-cytotoxic. Moreover, this method allows terminal sterilisation in a short time (3 min) and using accessible equipment.