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- Additive manufactured Poly("-caprolactone)-graphene scaffolds: Lamellar crystal orientation, mechanical properties and biological performancePublication . Biscaia, Sara; Silva, João C.; Moura, Carla; Viana, Tânia; Tojeira, Ana; Mitchell, Geoffrey R.; Pascoal-Faria, Paula; Ferreira, Frederico Castelo; Alves, NunoUnderstanding the mechano–biological coupling mechanisms of biomaterials for tissue engineering is of major importance to assure proper scaffold performance in situ. Therefore, it is of paramount importance to establish correlations between biomaterials, their processing conditions, and their mechanical behaviour, as well as their biological performance. With this work, it was possible to infer a correlation between the addition of graphene nanoparticles (GPN) in a concentration of 0.25, 0.5, and 0.75% (w/w) (GPN0.25, GPN0.5, and GPN0.75, respectively) in three-dimensional poly("-caprolactone) (PCL)-based scaffolds, the extrusion-based processing parameters, and the lamellar crystal orientation through small-angle X-ray scattering experiments of extruded samples of PCL and PCL/GPN. Results revealed a significant impact on the scaffold’s mechanical properties to a maximum of 0.5% of GPN content, with a significant improvement in the compressive modulus of 59 MPa to 93 MPa. In vitro cell culture experiments showed the scaffold’s ability to support the adhesion and proliferation of L929 fibroblasts (fold increase of 28, 22, 23, and 13 at day 13 (in relation to day 1) for PCL, GPN0.25, GPN0.5, and GPN0.75, respectively) and bone marrow mesenchymal stem/stromal cells (seven-fold increase for all sample groups at day 21 in relation to day 1). Moreover, the cells maintained high viability, regular morphology, and migration capacity in all the different experimental groups, assuring the potential of PCL/GPN scaffolds for tissue engineering (TE) applications.
- Rosin Based Composites for Additive ManufacturingPublication . Sousa, Dora; Biscaia, Sara; Viana, Tânia; Gaspar, Miguel Belbut; Mahendra, Vidhura; Mohan, Saeed D.; Mateus, Artur; Mitchell, GeoffreyRosins are the non-volatile exudates of pine resins with hydrophobic characteristics that are widely used as a precursor for many industrial applications. In this paper we discuss the nature, process and its applications as a matrix for a composite material for additive manufacturing. The composite material has been tailored to chemical and mechanical properties with respect to their applications.
- Development of novel 3D scaffolds using BioExtruder by varying the content of hydroxyapatite and silica in PCL matrix for bone tissue engineeringPublication . Pattanashetti, Nandini A.; Viana, Tânia; Alves, Nuno; Mitchell, Geoffrey; Kariduraganavar, Mahadevappa Y.Polycaprolactone (PCL) is considered as a most widely used biodegradable polymers in tissue engineering. But, PCL is also associated with certain limitations like, low stiffness, hydrophobic nature and limited cell affinity. These drawbacks are addressed in the present study by incorporating different wt% of silicon dioxide (SiO2) and hydroxyapatite (HAp) in the PCL matrix. 3D scaffolds were developed using a novel BioExtruder. The physicochemical properties, thermal stability and wettability of the composite scaffolds were studied systematically. Optical and Scanning Electron Microscopic images were analysed for morphological evaluation of the scaffolds. The pore size of the developed scaffolds increased from 290 to 315 μmwith increasing SiO2 content, as examined by scanning electron microscope. An improved compressive modulus of 68.82 MPa was observed for 15 wt% SiO2 incorporated composite scaffold. The in-vitro degradation study of the composite scaffolds demonstrated an increase in the degradation rate for PCL/HAp scaffolds, while no significant change was observed for SiO2 incorporated scaffolds. Further, the cytotoxicity and cell proliferation studies were carried out using L929 Mouse Fibroblasts and MG-63 Osteoblasts respectively. The developed scaffolds revealed no toxic effects towards the cellular response and an increase in cell proliferation of ≥90% was observed during 7 days of cell culture. Thus, the scaffolds were proved to be potential candidate for bone tissue engineering application, particularly the scaffold with 10 wt% SiO2 incorporation into PCL/HAp (75/15) composite has resulted into higher cell proliferative % and improved mechanical strength.
- 3D printed poly(E-caprolactone)/Hydroxyapatite scaffolds for bone tissue engineering: A comparative study on a Composite Preparation by Melt blending or solvent casting techniques and the influence of bioceramic content on scaffold propertiesPublication . Biscaia, Sara; Branquinho, Mariana V.; Alvites, Rui D.; Fonseca, Rita; Sousa, Ana Catarina; Pedrosa, Sílvia Santos; Caseiro, Ana R.; Guedes, Fernando; Patrício, Tatiana; Viana, Tânia; Mateus, Artur; Maurício, Ana C.; Alves, NunoBone tissue engineering has been developed in the past decades, with the engineering of bone substitutes on the vanguard of this regenerative approach. Polycaprolactone-based scaffolds are fairly applied for bone regeneration, and several composites have been incorporated so as to improve the scaffolds’ mechanical properties and tissue in-growth. In this study, hydroxyapatite is incorporated on polycaprolactone-based scaffolds at two different proportions, 80:20 and 60:40. Scaffolds are produced with two different blending methods, solvent casting and melt blending. The prepared composites are 3D printed through an extrusion-based technique and further investigated with regard to their chemical, thermal, morphological, and mechanical characteristics. In vitro cytocompatibility and osteogenic differentiation was also assessed with human dental pulp stem/stromal cells. The results show the melt-blending-derived scaffolds to present more promising mechanical properties, along with the incorporation of hydroxyapatite. The latter is also related to an increase in osteogenic activity and promotion. Overall, this study suggests polycaprolactone/hydroxyapatite scaffolds to be promising candidates for bone tissue engineering, particularly when produced by the MB method.
- A Novel Biomanufacturing System to Produce Multi-Material Scaffolds for Tissue Engineering: Concept and Preliminary ResultsPublication . Viana, T.; Biscaia, S.; Dabrowska, E.; Franco, M.; Carreira, P.; Morouço, P.; Alves, N.This research work aims to validate a new system that enables the fabrication of multimaterial 3D structures using poly(e-caprolactone) and sodium alginate for potential use in Tissue Engineering applications. To produce multi-material scaffolds for Tissue Engineering, accurate techniques are needed to obtain three-dimensional constructs with clinically appropriate size and structural integrity. This paper presents a novel biomanufacturing system which can fabricate 3D scaffolds with precise shape and porosity, through the control of all fabrication modules by an integrated computational platform. The incorporation of a clean flow unit and a camera makes it possible to produce scaffolds in a clean environment and provides a monitoring tool to analyse constructs during the production, respectively.
- Fabrication of Poly(𝜀-caprolactone) Scaffolds Reinforced with Cellulose Nanofibers, with and without the Addition of Hydroxyapatite NanoparticlesPublication . Morouço, Pedro; Biscaia, Sara; Viana, Tânia; Franco, Margarida; Pereira Malça, Cândida Maria dos Santos; Mateus, Artur; Monteiro de Moura, Carla Sofia; Ferreira, Frederico C.; Mitchell, Geoffrey; Alves, Nuno M.Biomaterial properties and controlled architecture of scaffolds are essential features to provide an adequate biological and mechanical support for tissue regeneration, mimicking the ingrowth tissues. In this study, a bioextrusion system was used to produce 3D biodegradable scaffolds with controlled architecture, comprising three types of constructs: (i) poly(𝜀-caprolactone) (PCL) matrix as reference; (ii) PCL-based matrix reinforced with cellulose nanofibers (CNF); and (iii) PCL-based matrix reinforced with CNF and hydroxyapatite nanoparticles (HANP). The effect of the addition and/or combination of CNF and HANP into the polymeric matrix of PCL was investigated, with the effects of the biomaterial composition on the constructs (morphological, thermal, and mechanical performances) being analysed. Scaffolds were produced using a single lay-down pattern of 0/90∘, with the same processing parameters among all constructs being assured. The performed morphological analyses showed a satisfactory distribution of CNF within the polymer matrix and high reliability was obtained among the produced scaffolds. Significant effects on surface wettability and thermal properties were observed, among scaffolds. Regarding the mechanical properties, higher scaffold stiffness in the reinforced scaffolds was obtained. Results from the cytotoxicity assay suggest that all the composite scaffolds presented good biocompatibility.The results of this first study on cellulose and hydroxyapatite reinforced constructs with controlled architecture clearly demonstrate the potential of these 3D composite constructs for cell cultivation with enhanced mechanical properties.
- Poly(ɛ-caprolactone) and Polyethylene Glycol Diacrylate-based Scaffolds for TMJ Bioengineered Disc ImplantsPublication . Francisco, Luís; Moura, Carla; Viana, Tânia; Ângelo, David; Morouço, Pedro; Alves, NunoThe temporomandibular joint (TMJ), articulation between the mandibular condyle and the temporal bone, is divided into two compartments (superior and inferior) by a fibrocartilaginous disc. The TMJ disc consists on an avascular and non-innervated tissue, with viscoelastic behavior. Mechanically, the TMJ disc experiences tensile, compressive and shear forces. TMJ disc displacement or degeneration could lead to severe intra-articular temporomandibular joint disorders (TMD). Despite the large number of current therapies/treatments, there is limited treatment options for severe intra-articular TMD. A strategy to solve this problem could be the use of an interposal material to substitute the damaged TMJ disc, which will gradually degrade and give rise to new tissue. In this work three options were used and tested, one using a thermoplastic material, poly(ε-caprolactone) (PCL), another using an photopolymerized hydrogel, polyethylene glycol diacrilate (PEGDA) and the third using the combination of the two materials. Obtained results demonstrated that that the combination of different materials could represent a significant advantage in the TMJ disc TE and in the cartilage TE in general.
- Production and Characterisation of PCL/ES Scaffolds for Bone Tissue EngineeringPublication . Biscaia, Sara I.; Viana, Tânia F.; Almeida, Henrique A.; Bártolo, Paulo J.The combination of bio-fillers with synthetic polymers has been an exciting route for developing tissue engineering scaffolds, in particular for bone tissue regeneration. In this study, poly(e{open}-caprolactone) (PCL) scaffolds were produced using an additive manufacturing technique and eggshell (ES) powder was used as a filler. The morphology of PCL and PCL/ES scaffolds were analysed and the effect of ES in the polymer matrix was characterized using techniques of Differential Scanning Calorimetry and Thermogravimetric Analysis, Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Diffraction (XRD). Morphological observation revealed that the incorporation of ES in the polymer matrix modifies the flow behaviour of the material in spite of the same processing parameters, resulting in a decrease of scaffold pore size. Thermal analysis showed that the addition of the bio-filler improves the crystallization properties and thermal stability of the PCL. FT-IR spectra of ES powder showed characteristic bands of calcium carbonate and processed materials spectra indicated no changes on the functional groups compared to non-processed materials. Crystalline nature of ES was demonstrated through a characteristic broad peak in XRD pattern around 30o, which was also observed in the composites XRD spectra. The results indicate the potential of ES powder to be used as a filler for bio-based polymer scaffold composites.