Percorrer por autor "Alves, Nuno"
A mostrar 1 - 4 de 4
Resultados por página
Opções de ordenação
- Development of a biocompatible hydrogel based on native temporomandibular joint extracellular matrix powderPublication . Trindade, Daniela; Moura, Carla; Calado, Cecília; Ângelo, David; Alves, NunoThe temporomandibular joint disc (TMJd) is an avascular and fibrocartilaginous tissue with low regeneration capacities. To date there is no permanent solution upon its damage. So, our group hypothesise that the combination of a synthetic material [poly(ethylene glycol) diacrylate, PEGDA] and decellularised matrices may be the answer, since it has the advantage of retaining extracellular matrix (ECM) components. For this purpose, lamb TMJd were decellularised with ethanol (96%) / acetone (99.5%) followed by an analysis to the ECM obtained. Afterwards, different concentrations of ECM powder were added to the PEGDA to obtain hybrid hydrogels. Their swelling capacities and mechanical behaviour (hydrated or dry) were assessed. Results show a reduction of the proteoglycans in the disc, except in the posterior region. Dried hydrogels with 2% ECM powder are the ones with the closer compressive modulus to the native disc, along with greater viscoelastic capacity, representing a possible approach to a TMJd replacement.
- Development of a biocompatible hydrogel based on native temporomandibular joint extracellular matrix powderPublication . Trindade, Daniela; Moura, Carla; Calado, Cecília; Ângelo, David; Alves, NunoThe temporomandibular joint disc (TMJd) is an avascular and fibrocartilaginous tissue with low regeneration capacities. To date there is no permanent solution upon its damage. So, our group hypothesise that the combination of a synthetic material [poly(ethylene glycol) diacrylate, PEGDA] and decellularised matrices may be the answer, since it has the advantage of retaining extracellular matrix (ECM) components. For this purpose, lamb TMJd were decellularised with ethanol (96%)/ acetone (99.5%) followed by an analysis to the ECM obtained. Afterwards, different concentrations of ECM powder were added to the PEGDA to obtain hybrid hydrogels. Their swelling capacities and mechanical behaviour (hydrated or dry) were assessed. Results show a reduction of the proteoglycans in the disc, except in the posterior region. Dried hydrogels with 2% ECM powder are the ones with the closer compressive modulus to the native disc, along with greater viscoelastic capacity, representing a possible approach to a TMJd replacement.
- From scans to steps: elevating stroke rehabilitation with 3D-printed ankle-foot orthosesPublication . Silva, Rui; Morouço, Pedro; Ricardo, Diogo; Campos, Inês; Alves, Nuno; Veloso, António P.Background: The integration of advanced 3D scanning and additive manufacturing technologies in stroke rehabilitation offers promising advancements in the design and production of ankle-foot orthoses. These technological innovations are progressively recognized for their potential to provide more precise and customized orthotic solutions for individuals with stroke-related impairments. Objectives: The primary aim of this study was to biomechanically test and validate the effectiveness of custom ankle-foot orthoses produced through additive manufacturing technology using data captured by a novel photogrammetric scanning system. The customized orthosis was compared with a standard prefabricated orthosis to assess their relative effectiveness in improving gait dynamics and patient satisfaction in stroke rehabilitation. Methods: Participants with equinovarus deformity, a common consequence of stroke, were fitted with custom ankle-foot orthoses, alongside conventional prefabricated orthoses. The study utilized the Qualisys® motion analysis system for comprehensive biomechanical gait analysis, and the QUEST questionnaire was employed to capture participant feedback on both types of orthoses. Detailed comparisons of gait dynamics were conducted using Statistical Parametric Mapping with each orthosis. Results: The study revealed notable kinematic and kinetic differences between the custom and prefabricated orthoses. The custom orthoses demonstrated superior performance in enhancing gait efficiency, symmetry, and safety. Patient feedback favored the customized orthoses over the prefabricated variants, with higher scores in comfort, fit, and overall effectiveness. Conclusions: This research underscores the effectiveness of custom orthoses produced through additive manufacturing technology for stroke rehabilitation. By offering a comprehensive evaluation of orthotic interventions and establishing a comparative framework, the study serves as a reference point for future research, advocating for a more personalized and evidence-based approach in orthotic design for improving the quality of life of stroke survivors.
- Ovine model as a temporomandibular disc substitute: characterisation and the outcomes of freezing storagePublication . Trindade, Daniela; Calado, Cecília; Alves, Nuno; Moura, CarlaThe temporomandibular joint (TMJ) is a ginglymoarthrodial joint that comprises a fibrocartilaginous disc that is highly predisposed to suffer from trauma or degenerative events, leading to disorders in the condyle–disc complex. The use of decellularized tissues has attracted interest in the tissue engineering (TE) field as an intact extracellular matrix can be obtained [1]. To this end, the ovine model was the first choice for a TMJ TE approach as they are easy to obtain, inexpensive and present an easily accessible surgical site [2]. When biological materials are used, their conservation should be taken into consideration, as sometimes it is not possible to test them immediately after extraction. With this, the present study aims to characterise the ovine disc, and determine its maximum freezing-time storage without alterations in its morphological and compression properties and biochemical composition. For this, two storage conditions were tested: (i) freezing at −20 ◦C in phosphate buffered saline (PBS) solution and thaw at 4 ◦C (PBS + 4 ◦C) and (ii) wrapping the discs in PBS embedded gauze and freezing at −20 ◦C followed by thaw at room temperature (RT) in PBS (Gauze + RT). Moreover, different time intervals were assessed: 1, 7 and 14 days. Results showed that the native disc presented a thickness of 1.62 ± 0.674 mm, weighted 0.385 ± 0.029 g and had a compressive modulus of 2.36 ± 0.072 MPa. Regarding biochemical composition, collagen content was higher in the central zone, whereas glycosaminoglycans were higher in the lateral and posterior zone. After performing both storage methods, morphological characteristics were minimally altered, but the biochemical content was significantly affected. After the 14-day experiments, there was an increase of about 30% in the compression modulus for Gauze + RT when compared to the fresh native disc, while for the PBS + 4 ◦C no changes were observed. This study determined that freezing the ovine discs may lead to changes in the native properties, indicating that when it is necessary to store them, these changes should be taken into consideration in future studies.