Bioresorbable films of polycaprolactone blended with poly(lactic acid) or poly(lactic-co-glycolic acid).

Recent complications on the use of polypropylene meshes for hernia repair has led to the development of meshes or films, which were based on resorbable polymers such as polycaprolactone (PCL), polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA). These materials are able to create suitable bioactive environment for the growth and development of cells. In this research, we mainly focused on the relations among structure, mechanical performance and biocompatiblity of PCL/PLA and PCL/PLGA and blends prepared by solution casting. The films were characterized regarding the chemical structure, morphology, physicochemical properties, cytotoxicity, biocompatibility and cell growth. All the films showed high tensile strength ranging from 9.5 to 11.8 MPa. SAXS showed that the lamellar stack structure typical for PCL was present even in the blend films while the morphological parameters of the stacks varied slightly with the content of PLGA or PLA in the blends. WAXS indicated preferential orientation of crystallites (and thus, also the lamellar stacks) in the blend films. In vitro studies revealed that PCL/PLGA films displayed better cell adhesion, spreading and proliferation than PCL/PLA and PCL films. Further the effect of blending on the degradation was investigated, to understand the significant variable within the process that could provide further control of cell adhesion. The results showed that the investigated blend films are promising materials for biomedical applications.

Platelet lysate for expansion or osteogenic differentiation of bone marrow mesenchymal stem cells for 3D tissue constructs.

Background: The use of mesenchymal stem cells (MSCs) for the development of tissue-engineered constructs has advanced in recent years. However, future clinically approved products require following good manufacturing practice (GMP) guidelines. This includes using alternatives to xenogeneic-derived cell culture supplements to avoid rejection of the transplants. Consequently, human platelet lysate (PLT) has been adopted as an affordable and effective alternative to foetal bovine serum (FBS) in traditional 2D cultures. However, little is known about its effect in more advanced 3D culture systems. Methods: We evaluated bone marrow MSCs (BMSCs) proliferation and CD marker expression in cells expanded in FBS or PLT-supplemented media. Differentiation capacity of the BMSCs expanded in the presence of the different supplements was evaluated in 3D type I collagen hydrogels. Furthermore, the effects of the supplements on the process of differentiation were analyzed by using qPCR and histological staining. Results: Cell proliferation was greater in PLT-supplemented media versus FBS. BMSCs expanded in PLT showed similar osteogenic differentiation capacity in 3D compared with FBS expanded cells. In contrast, when cells were 3D differentiated in PLT they showed lower osteogenesis versus the traditional FBS protocol. This was also the case for adipogenic differentiation, in which FBS supplementation was superior to PLT. Conclusions: PLT is a superior alternative to FBS for the expansion of MSCs without compromising their subsequent differentiation capacity in 3D. However, differentiation in PLT is impaired. Thus, PLT can be used to reduce the time required to expand the necessary cell numbers for development of 3D tissue engineered MSC constructs.

Efficacy of Nerve-Derived Hydrogels to Promote Axon Regeneration Is Influenced by the Method of Tissue Decellularization.

Injuries to large peripheral nerves are often associated with tissue defects and require reconstruction using autologous nerve grafts, which have limited availability and result in donor site morbidity. Peripheral nerve-derived hydrogels could potentially supplement or even replace these grafts. In this study, three decellularization protocols based on the ionic detergents sodium dodecyl sulfate (P1) and sodium deoxycholate (P2), or the organic solvent tri-n-butyl phosphate (P3), were used to prepare hydrogels. All protocols resulted in significantly decreased amounts of genomic DNA, but the P2 hydrogel showed the best preservation of extracellular matrix proteins, cytokines, and chemokines, and reduced levels of sulfated glycosaminoglycans. In vitro P1 and P2 hydrogels supported Schwann cell viability, secretion of VEGF, and neurite outgrowth. Surgical repair of a 10 mm-long rat sciatic nerve gap was performed by implantation of tubular polycaprolactone conduits filled with hydrogels followed by analyses using diffusion tensor imaging and immunostaining for neuronal and glial markers. The results demonstrated that the P2 hydrogel considerably increased the number of axons and the distance of regeneration into the distal nerve stump. In summary, the method used to decellularize nerve tissue affects the efficacy of the resulting hydrogels to support regeneration after nerve injury.