In craniofacial tissue regeneration, the current gold standard treatment is autologous bone grafting, however, it presents some disadvantages. Although new alternatives have emerged there is still an urgent demand of biodegradable scaffolds to act as extracellular matrix in the regeneration process. A potentially useful element in bone regeneration is strontium. It is known to promote stimulation of osteoblasts while inhibiting osteoclasts resorption, leading to neoformed bone. The present paper reports the preparation and characterization of strontium (Sr) containing hybrid scaffolds formed by a matrix of ionically cross-linked chitosan and microparticles of poly(ε-caprolactone) (PCL). These scaffolds of relatively facile fabrication were seeded with osteoblast-like cells (MG-63) and human bone marrow mesenchymal stem cells (hBMSCs) for application in craniofacial tissue regeneration. Membrane scaffolds were prepared using chitosan:PCL ratios of 1:2 and 1:1 and 5 wt % Sr salts. Characterization was performed addressing physico-chemical properties, swelling behavior, in vitro biological performance and in vivo biocompatibility. Overall, the composition, microstructure and swelling degree (≈245%) of scaffolds combine with the adequate dimensional stability, lack of toxicity, osteogenic activity in MG-63 cells and hBMSCs, along with the in vivo biocompatibility in rats allow considering this system as a promising biomaterial for the treatment of craniofacial tissue regeneration.
The search of suitable combinations of stem cells, biomaterials and scaffolds manufacturing methods have become a major focus of research for bone engineering. The aim of this study was to test the potential of dental pulp stem cells to attach, proliferate, mineralize and differentiate on 3D printed polycaprolactone (PCL) scaffolds. A 100% pure Mw: 84,500 ± 1000 PCL was selected. 5 × 10 × 5 mm3 parallelepiped scaffolds were designed as a wood-pilled structure composed of 20 layers of 250 μm in height, in a non-alternate order ([0,0,0,90,90,90°]). 3D printing was made at 170 °C. Swine dental pulp stem cells (DPSCs) were extracted from lower lateral incisors of swine and cultivated until the cells reached 80% confluence. The third passage was used for seeding on the scaffolds. Phenotype of cells was determined by flow Cytometry. Live and dead, Alamar blue™, von Kossa and alizarin red staining assays were performed. Scaffolds with 290 + 30 μm strand diameter, 938 ± 80 μm pores in the axial direction and 689 ± 13 μm pores in the lateral direction were manufactured. Together, cell viability tests, von Kossa and Alizarin red staining indicate the ability of the printed scaffolds to support DPSCs attachment, proliferation and enable differentiation followed by mineralization. The selected material-processing technique-cell line (PCL-3D printing-DPSCs) triplet can be though to be used for further modelling and preclinical experiments in bone engineering studies.
Electrospinning has proven to be a suitable technique for the production of small diameter tubes, with diverse applications, in the field of tissue engineering. In this work, tubular scaffolds were prepared by electrospinning a polycaprolactone/polylactic-co-glycolic acid (PLGA) blend and then treated with polypyrrole plasma for a possible application with urethral tissue. Scanning electron microscopy micrographs showed that for 10% and 20% of the PLGA in the blend, the microfibers, of varying diameters, were free of defects. The elastic modulus of the tubular scaffolds was highest (19 MPa) at 30% of PLGA, while the strain to break was maximum at 10-20% PLGA. However, at 30% of PLGA, within the polycaprolactone, the mechanical synergy (strain at break) was lost. Epithelial cells and smooth muscle cells' viability on 80/20 blends was high. When this scaffold was treated for 15 min with polypyrrol plasma, an improvement in cell viability was observed, with few polypyrrol particles being deposited and little scaffold degradation. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy showed the presence of NH, C-N, and CN groups as the chemical groups responsible of this behavior. Therefore, these scaffolds with the polypyrrole surface treatment can be used in the urethra tissue engineering.
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