Loading...
9 results
Search Results
Now showing 1 - 9 of 9
- Challenges and Innovations in Osteochondral Regeneration: Insights from Biology and Inputs from Bioengineering toward the Optimization of Tissue Engineering StrategiesPublication . Morouço, P.; Fernandes, C.; Lattanzi, W.Due to the extremely high incidence of lesions and diseases in aging population, it is critical to put all efforts into developing a successful implant for osteochondral tissue regeneration. Many of the patients undergoing surgery present osteochondral fissure extending until the subchondral bone (corresponding to a IV grade according to the conventional radiographic classification by Berndt and Harty). Therefore, strategies for functional tissue regeneration should also aim at healing the subchondral bone and joint interface, besides hyaline cartilage. With the ambition of contributing to solving this problem, several research groups have been working intensively on the development of tailored implants that could promote that complex osteochondral regeneration. These implants may be manufactured through a wide variety of processes and use a wide variety of (bio)materials. This review aimed to examine the state of the art regarding the challenges, advantages, and drawbacks of the current strategies for osteochondral regeneration. One of the most promising approaches relies on the principles of additive manufacturing, where technologies are used that allow for the production of complex 3D structures with a high level of control, intended and predefined geometry, size, and interconnected pores, in a reproducible way. However, not all materials are suitable for these processes, and their features should be examined, targeting a successful regeneration.
- Osteoarthritis, Exercise, and Tissue Engineering: A Stimulating Triad for Health ProfessionalsPublication . Morouço, Pedro; Fernandes, Cristiana; Santos-Rocha, RitaOsteoarthritis (OA) is a degenerative disease, promoted by abnormal chronic mechanical loading over the joint, for instance, due to excessive body mass. Patients frequently report pain, fatigue, and limitations in specific functional daily activities. Regarding the treatment of OA, two nonpharmacological options are available. However, it is not clear which type and intensity of exercise have better outcomes in treatment and how tissue engineering can be a promising field due to the mechanical load implants will suffer. The aims of this work were to investigate (1) the main characteristics, prevalence, and consequences of OA; (2) the exercise prescription guidelines and whether exercise interventions have a positive effect on OA treatment; and (3) the novel improvements on tissue engineering for OA treatment. Both patients and practitioners should be aware that benefits may come from prescribed and supervised exercise. Recent studies have highlighted that an optimal balance between exercise and nutritional income should be widely recommended. Regarding tissue engineering, significant steps towards the development of implants that mimic the native tissue have been taken. Thus, further studies should focus on the impact that exercise (repetitive loading) might have on cartilage regeneration. Finally, suggestions for future research were proposed.
- Four-dimensional (bio-)printing: A review on stimuli-responsive mechanisms and their biomedical suitabilityPublication . Morouço, Pedro; Azimi, Bahared; Milazzo, Mario; Mokhtari, Fatemeh; Fernandes, Cristiana; Reis, Diana; Danti, SerenaThe applications of tissue engineered constructs have witnessed great advances in the last few years, as advanced fabrication techniques have enabled promising approaches to develop structures and devices for biomedical uses. (Bio-)printing, including both plain material and cell/material printing, o ers remarkable advantages and versatility to produce multilateral and cell-laden tissue constructs; however, it has often revealed to be insu cient to fulfill clinical needs. Indeed, three-dimensional (3D) (bio-)printing does not provide one critical element, fundamental to mimic native live tissues, i.e., the ability to change shape/properties with time to respond to microenvironmental stimuli in a personalized manner. This capability is in charge of the so-called “smart materials”; thus, 3D(bio-)printing these biomaterials is a possible way to reach four-dimensional (4D) (bio-)printing. We present a comprehensive review on stimuli-responsive materials to produce scaffolds and constructs via additive manufacturing techniques, aiming to obtain constructs that closely mimic the dynamics of native tissues. Our work deploys the advantages and drawbacks of the mechanisms used to produce stimuli-responsive constructs, using a classification based on the target stimulus: humidity, temperature, electricity, magnetism, light, pH, among others. A deep understanding of biomaterial properties, the scaffolding technologies, and the implant site microenvironment would help the design of innovative devices suitable and valuable for many biomedical applications.
- Smart Materials for Biomedical Applications: The Usefulness of Shape-Memory PolymersPublication . Fernandes, Cristiana; Heggannavar, Geetha B.; Kariduraganavar, Mahadevappa Y.; Mitchell, Geoffrey; Alves, Nuno; Morouço, PedroThis review describes available smart biomaterials for biomedical applications. Biomaterials have gained special attention because of their characteristics, along with biocompatibility, biodegradability, renewability, and inexpensiveness. In addition, they are also sensitive towards various stimuli such as temperature, light, magnetic, electro, pH and can respond to two or more stimuli at the same time. In this manuscript, the suitability of stimuli-responsive smart polymers was examined, providing examples of its usefulness in the biomedical applications.
- Smart Polymers in Drug Delivery ApplicationsPublication . Heggannavar, Geetha B.; Achari, Divya; Fernandes, Cristiana; Mitchell, Geoffrey; Morouço, Pedro; Kariduraganavar, Mahadevappa Y.The most important components of living cells such as carbohydrates, proteins and nucleic acids are the polymeric molecules. Nature utilizes polymers both as constructive elements and as a part of the complicated cell machinery of living things. The rapid advancement in biomedical research has led to many creative applications for biocompatible polymers. With the development of newer and more potent drugs, a parallel expansion in more sophisticated drug delivery systems becomes mandatory. Smart polymeric drug delivery systems can respond to environmental changes and consequently, alter their properties reversibly enabling an efficient and safe drug delivery. This review comprehensively discusses various aspects of these polymers classified in different categories as per the type of stimulus.
- A review of additive manufacturing studies for producing customized ankle-foot orthosesPublication . Silva, Rui; Veloso, António; Alves, Nuno; Fernandes, Cristiana; Morouço, PedroAnkle-foot orthoses (AFO) are prescribed to improve the patient’s quality of life. Supporting weak muscles or restraining spastic muscles leads to smoother and more stable locomotion. Commonly, AFO are made using thermoplastic vacuum forming, which requires a long time for production and has limited design options. Additive manufacturing (AM) can solve this problem, leading to a faster and cheaper solution. This review aimed to investigate what is the state-of-art using AM for AFO. Evaluating the used manufacturing processes, customization steps, mechanical properties, and biomechanical features in humans would provide significant insights for further research. The database searches combined AM and AFO with no year or publication type restrictions. Studies must have examined outcomes on human participants with the orthoses built by AM. Other types of orthotic devices or different manufacturing techniques were excluded. Nineteen studies met the inclusion criteria. As stated by having all studies conducted in the last nine years, this is a very recent domain. Different AM processes have been used, with the majority relying on Fused Deposition Modeling. Overall, the manuscripts’ quality is deficient, which is critical to promoting further studies with higher samples. Except for one paper, AM-printed AFO was comparable or superior to the thermoplastic vacuum forming AFO in mechanical tests, kinematics, kinetics, and participant feedback.
- Scaffolds and Bioreactor characterisation towards Bone Regeneration: proposal of a computer-aided design modelPublication . Fernandes, Cristiana Henriques; Vieira, Paula Cristina Rodrigues Pascoal Faria; Ascenso, Rita Margarida Teixeira; Moura, Carla Sofia Monteiro deOver the last decades, the number of occupational accidents associated with bone problems has increased leading to a growing concern worldwide. Currently, autografts, allografts, and xenografts are used for bone regeneration. However, their application have associated risks. Tissue Engineering (TE) has investigated solutions to address these problems, specifically through the production of temporary supports, also called biocompatible and biodegradable scaffolds, which allow cell adhesion and proliferation, providing mechanical support to the formation of new bone tissue. These three-dimensional supports must meet certain requirements, namely mechanical and biological. Upon its production and in order to give an appropriate answer, the material must be biocompatible as well as the products derived from its degradation. The combination of materials and structure with the technique to be used will directly influence their physical and chemical properties and, consequently, their action in contributing to bone regeneration. Thus, the focus of this dissertation is to perform a critical analysis of the state-of-art in bone TE and present a proposal of an optimized temporary support geometry. For this, the choice of biomaterials, cells and their culture conditions (static vs. dynamic) and/or the addition of growth factors for the repair of large bone defects are addressed is addressed.
- Characterization of Biocompatible Poly(Ethylene Glycol)-Dimethacrylate Hydrogels for Tissue EngineeringPublication . Lopes, João; Fonseca, Rita; Viana, Tânia; Fernandes, Cristiana; Morouço, Pedro; Moura, Carla; Biscaia, SaraTissue Engineering depends on broadly techniques to regenerate tissues and/or organ functions. To do so, tailored polymeric and/or hydrogel scaffolds may be used to ensure the appropriate regeneration. Hydrogels are suitable materials for constructing cell-laden matrices as they can be produced with incorporation of cells and rapidly cross-linked in situ through photopolymerisation reactions. Measurement of the polymerization degree, as well as resistance to compression and water retention are fundamental tests to evaluate the characteristics of hydrogels. In this work, free-radical polymerisation of poly(ethylene glycol)-dimethacrylate (PEGDMA) in UV light was assessed. Several hydrogels with different photoinitiator and water contents were produced to evaluate their influence on hydrogels behaviour. Experiments showed that variations on water and photoinitiator content induce changes in the physical and chemical behaviour of hydrogels. As it was found, water content prevents polymerisation to occur and reduces the mechanical properties of hydrogels weakening them. Furthermore, differences were found in varying water content from 15 to 30%, since this increase turned hydrogels more fragile and increase their stabilization time for water retention.
- Comprehensive review on full bone regeneration through 3D printing approachesPublication . Fernandes, Cristiana; Moura, Carla; Ascenso, Rita M.T.; Amado, Sandra; Alves, Nuno; Pascoal-Faria, PaulaOver the last decades, the number of work accidents associated with bone fractures has increased leading to a growing concern worldwide. Currently, autografts, allografts, and xenografts are used for bone regeneration. However, their application has associated risks. Tissue engineering (TE) has brought solutions to address these problems, through the production of temporary supports, providing mechanical support to the formation of new bone tissue and biocompatible and biodegradable scaffolds, which allow cell adhesion and proliferation to ensure bone formation. The combination of materials and structure with the technique to be used will directly influence their physical and chemical properties and, consequently, their action in contributing to bone regeneration. Thus, the focus of this chapter is to perform an exhaustive literature review and a critical analysis of the state of the art in bone TE and present a proposal of an optimized temporary support geometry for bone regeneration in case of large bone defects. For this, it was listed and identified the best choice of biomaterials, fabrication method, cell type and their culture conditions (static vs. dynamic), and/or the inclusion of growth factors for the repair of large bone defects.