The aim of the present review was to highlight some of the available processes for cartilage repair and regeneration. Considering the high impact that cartilage degeneration has in the quality of life, in an aging society, efforts to promote better treatments are crucial. The current available processes have advantages and drawbacks, that should be further investigated, aiming to obtain tailored and successful repair. Finally, some suggestions for tissue engineering strategies are presented, so that the scientific community can debate pros and cons to be investigated.

The in vivo degradation processes by which scaffolds degrade and are replaced by neo-tissue are complex and may be influenced by many factors, including environmental conditions, material properties, porosity and 3D architecture. The present study is focused on the influence of design parameters, filament distance (FD) and lay-down pattern, on the degradation kinetics of Polycaprolactone (PCL) scaffolds obtained via BioExtrusion. Through the variation of design parameters it was possible to obtain two groups of scaffolds with distinct pore geometry and size. The in vitro degradation was performed in simulated body fluid (SBF) and in phosphate buffer solution (PBS) for six months. Our results highlight a more complex degradation pattern of the scaffolds in SBF than in PBS, probably related to a mineral deposition. Significant statistical differences in weight loss values at month 6, allowed us to conclude that degradation kinetics of PCL scaffolds is strongly influenced by the pore size.

The most promising strategies in tissue engineering involve the integration of a triad of biomaterials, living cells, and biologically active molecules to engineer synthetic environments that closely mimic the healing milieu present in human tissues, and that stimulate tissue repair and regeneration. To be clinically effective, these environments must replicate, as closely as possible, the main characteristics of the native extracellular matrix (ECM) on a cellular and subcellular scale. Photo-fabrication techniques have already been used to generate 3D environments with precise architectures and heterogeneous composition, through a multi-layer procedure involving the selective photocrosslinking reaction of a light-sensitive prepolymer. Cells and therapeutic molecules can be included in the initial hydrogel precursor solution, and processed into 3D constructs. Recently, photo-fabrication has also been explored to dynamically modulate hydrogel features in real time, providing enhanced control of cell fate and delivery of bioactive compounds. This paper focuses on the use of 3D photo-fabrication techniques to produce advanced constructs for tissue regeneration and drug delivery applications. State-of-the-art photo-fabrication techniques are described, with emphasis on the operating principles and biofabrication strategies to create spatially controlled patterns of cells and bioactive factors. Considering its fast processing, spatiotemporal control, high resolution, and accuracy, photo-fabrication is assuming a critical role in the design of sophisticated 3D constructs. This technology is capable of providing appropriate environments for tissue regeneration, and regulating the spatiotemporal delivery of therapeutics.

Tissue engineering, often referred to as regenerative medicine and reparative medicine, is an interdisciplinary field that necessitates the combined effort of cell biologists, engineers, material scientists, mathematicians, geneticists, and clinicians toward the development of biological substitutes that restore, maintain, or improve tissue function. It has emerged as a rapidly expanding approach to address the organ shortage problem and comprises tissue regeneration and organ substitution. Cells placed on/or within constructs is the most common strategy in tissue engineering. Successful cell seeding depends on fast attachment of cell to scaffolds, high cell survival and uniform cell distribution. The seeding time is strongly dependent on the scaffold material and architecture. Scaffolds provide an initial biochemical substrate for the novel tissue until cells can produce their own extra-cellular matrix (ECM). Thus scaffolds not only define the 3D space for the formation of new tissues, but also serve to provide tissues with appropriate functions. These scaffolds are often critical, both in vivo (within the body) or in vitro (outside the body) mimicking in vivo conditions. Additive fabrication processes represent a new group of non-conventional fabrication techniques recently introduced in the biomedical engineering field. In tissue engineering, additive fabrication processes have been used to produce scaffolds with customised external shape and predefined internal morphology, allowing good control of pore size and pore distribution. This article provides a comprehensive state-of-the-art review of the application of biomanufacturing additive processes in the field of tissue engineering. New and moving trends in biomanufacturing technologies and the concept of direct cell-printing technologies are also discussed.

This study aims to assess the in vivo performance of cell–scaffold constructs composed of goat marrow stromal cells (GBMCs) and SPCL (a blend of starch with polycaprolactone) fibre mesh scaffolds at different stages of development, using an autologous model. GBMCs from iliac crests were seeded onto SPCL scaffolds and in vitro cultured for 1 and 7 days in osteogenic medium. After 1 and 7 days, the constructs were characterized for proliferation and initial osteoblastic expression by alkaline phosphatase (ALP) activity. Scanning electron microscopy analysis was performed to investigate cellularmorphology and adhesion to SPCL scaffolds. Non-critical defects (diameter 6 mm, depth 3 mm) were drilled in the posterior femurs of four adult goats from which bone marrow and serum had been collected previously. Drill defects alone and defects filled with scaffolds without cells were used as controls. After implantation, intravital fluorescence markers, xylenol orange, calcein green and tetracycline, were injected subcutaneously after 2, 4 and 6 weeks, respectively, for bone formation and mineralization monitoring. Subsequently, samples were stained with L´evai–Laczk´o for bone formation and histomorphometric analysis. GBMCs adhered and proliferated on SPCL scaffolds and an initial differentiation into pre-osteoblasts was detected by an increasing level of ALP activity with the culture time. In vivo experiments indicated that bone neoformation occurred in all femoral defects. The results obtained provided important information about the performance of SPCL–GBMC constructs in an orthotopic goat model that enabled future studies to be designed to investigate in vivo the functionality of SPCL–GBMC constructs in more complex models, viz. critical sized defects, and to evaluate the influence of in vitro cultured autologous cells in the healing and bone regenerative process

Mesenchymal stem cells have a great potential for application in cell based therapies, such as tissue engineering. Adipose derived stem cells have shown the capacity to differentiate into several lineages, and have been isolated in many animal species. Dog is a very relevant animal model to study several human diseases and simultaneously an important subject in veterinary medicine. Thus, in this study we assessed the potential of canine adipose tissue derived stem cells (cASCs) to differentiate into the osteogenic and chondrogenic lineages by performing specific histological stainings, and studied the cell passaging effect on the cASCs stemness and osteogenic potential. We also evaluated the effect of the anatomical origin of the adipose tissue, namely from abdominal subcutaneous layer and from greater omentum. The stemness and osteogenic differentiation was followed by real time RT-PCR analysis of typical markers of mesenchymal stem cells (MSCs) and osteoblasts.</p> <p>The results obtained revealed that cASCs exhibit a progressively decreased expression of the MSCs markers along passages and also a decreased osteogenic differentiation potential. In the author’s knowledge, this work presents the first data about the MSCs markers profile and osteogenic potential of cASCs along cellular expansion. Moreover, the obtained data showed that the anatomical origin of the adipose tissue has an evident effect in the differentiation potential of the ASCs. Due to the observed resemblances with the human ASCs, we conclude that canine ASCs can be used as a model cells in tissue engineering research envisioning human applications

In the Tissue Engineering area, it is common the use biomaterials composed by matrices with a high percentage of collagen, which are perfect to tissue rebuilding and Regenerative Medicine. It is also known that the collagen support cell migration and vascularization process. However, in recent decades, the use of polymers as scaffolding matrices in tissue regeneration has been widely extended. Polymers can be modified to gather the desired biodegradability and bioactivity characteristics, and they have a wide variety of mechanical characteristics, which gives them different functions in accordance with the material component. The functions that are most indorsed to these biomaterials are drug delivery and temporary prosthesis. Thus, in this work, poly (L-lactic acid) (PLLA) films with different wettability (standard / super-hydrophobic) (S and SH, respectively) were used in an in vivo subcutaneous implant in rats (Rattus norvegicus) in order to measure the inflammatory response, using immunohistochemistry technique. The semi-crystalline polymer poly (L-lactic acid) is an aliphatic polyester which is characterized by good biodegradability, biocompatibility and versatility, and it has reasonable mechanical and processability properties in fiber formation. After implantation, it occurs an immune response in the surgery local, and depending on the implanted materials characteristics, the inflammatory reaction will vary. For this study 18 rats were used, 9 were implanted with PLLA S and 9 with PLLA SH. Each rat was implanted with 6 PLLA discs in 6 different sites, 4 subcutaneously and 2 intramuscularly. After collecting the samples (n=108), immunohistochemistry was performed for three antibodies: CD3 (T lymphocytes), CD163 (M2 macrophages) and CD68 (Total macrophages). There was a decrease in the number of cells identified around the site of the implant site for both biomaterials, where it was possible to verify that the superhydrophobic PLLA promoted a minor inflammatory response. Therefore, it was observed that for both biomaterials the inflammatory reaction decreased over time and that the adaptive immune system was not strongly activated.

Silica aerogel is a material composed of SiO2 that has exceptional physical properties when utilized for tissue engineering applications. Poly-ε-caprolactone (PCL) is a biodegradable polyester that has been widely used for biomedical applications, namely as sutures, drug carriers, and implantable scaffolds. Herein, a hybrid composite of silica aerogel, prepared with two different silica precursors, tetraethoxysilane (TEOS) or methyltrimethoxysilane (MTMS), and PCL was synthesized to fulfil bone regeneration requirements. The developed porous hybrid biocomposite scaffolds were extensively characterized, regarding their physical, morphological, and mechanical features. The results showed that their properties were relevant, leading to composites with different properties. The water absorption capacity and mass loss were evaluated as well as the influence of the different hybrid scaffolds on osteoblasts' viability and morphology. Both hybrid scaffolds showed a hydrophobic character (with water contact angles higher than 90°), low swelling (maximum of 14%), and low mass loss (1-7%). hOB cells exposed to the different silica aerogel-PCL scaffolds remained highly viable, even for long periods of incubation (7 days). Considering the obtained results, the produced hybrid scaffolds may be good candidates for future application in bone tissue engineering.

As nanofibras são fibras cujo diâmetro se encontra abaixo de 100 nm e que possuem propriedades físico-químicas únicas, incluindo alta porosidade, alta relação área/volume superficial e versatilidade oferecida pela grande diversidade de materiais disponíveis para a sua síntese. Essas características fazem das nanofibras um dos assuntos mais em foco da área da pesquisa biomédica. As nanofibras podem ser produzidas através de vários métodos, sendo o electrospinning o mais utilizado e aplicado em múltiplas áreas. No que se refere à medicina, as nanofibras podem ser usadas em material de penso, administração de medicamentos, biossensores, engenharia de tecidos e medicina regenerativa. Ademais, a superfície destes nanomateriais unidimensionais pode ser facilmente modificada para obter nanofibras com as características desejadas consoante a necessidade médica pretendida. Nesta monografia, são apresentados aspetos relativos ao desenvolvimento farmacêutico de nanofibras e avanços recentes no que diz respeito aos seus métodos de produção, caracterização e aplicações biomédicas. Para além disso, também são discutidas perspetivas futuras relacionadas com o scaling-up tecnológico e a viabilidade de passar as nanofibras para a prática clínica.Em conjunto com a realização do trabalho monográfico, durante o periodo de estágio curricular, realizei também um estágio em farmácia comunitária no qual aprendi o papel activo que o farmacêutico possui a nível de farmácia comunitária. Para além disso, tive a oportunidade de fazer um estágio curricular em Indústria Farmacêutica- Labesfal-Fresenius-Kabi, no departamento do controlo de qualidade.

The big news of this new therapeutic line is mainly the customization of the products to theneeds of a particular patient, striving for uniqueness and specificity.The exponential increase of scientific knowledge in the areas of biotechnology,medicine and cell biology has led to the evolution of very promising new therapies indisease prevention, control and treatment.Advanced therapy medicinal products (ATMP) have revolutionized the field of innovative therapies by offering therapeutic solutions for diseases whose treatmentes were limited or nonexistente. As such a new, innovative, complex and heterogeneous sector, strict regulatory scrutiny is of the most importance and the European Medicines Agency (EMA) has set up the Committee for Advanced Therapies (CAT), which is responsible for regulating and promoting development of this sector. Most of the entities involved in the development of this products are smal and medium enterprises (SMEs), hospitals and academic institutions, entities with limited human and financial resources, barriers that need to be overcome in order to boost this market. Some measures are underway to assist these entitites with regard to the regulatory and economic aspects, including thereduction of fees or opinion on the classification of products. Advanced therapies may in future be seen as a therapeutic pillar of health care, filling areas not covered by so-called conventional therapies, serving to increase the quality and average life expectancy of people with rare diseases hitherto inhealed.