Marta L. Alves da Silva

The Influence of Patterned Nanofiber Meshes on Human Mesenchymal Stem Cell Osteogenesis

A specially designed electroconductive collector enables the electrospinning of P-NFM composed of areas of parallel/uniaxially aligned fibers and areas of random/orthogonal nanofiber distribution. The biological relevance of P-NFM is demonstrated using hBMSCs as an autologous cell source. The structures induce cell orientation along the uniaxially aligned fibers, mainly during earlier culturing periods under basal and osteogenic differentiation conditions. The microtopography of the P-NFM also controls the deposition of mineralized extracellular matrix along the pre-defined fiber direction. Genotypic characterization confirms the successful differentiation into the osteogenic lineage.

In vitro and in vivo assessment of magnetically actuated biomaterials and prospects in tendon healing

AIM To expand our understanding on the effect of magnetically actuated biomaterials in stem cells, inflammation and fibrous tissue growth. MATERIALS & METHODS Magnetic biomaterials were obtained by doping iron oxide particles into starch poly-ϵ-caprolactone (SPCL) to create two formulations, magSPCL-1.8 and 3.6. Stem cell behavior was assessed in vitro and the inflammatory response, subcutaneously in Wistar rats. RESULTS Metabolic activity and proliferation increased significantly overtime in SPCL and magSPCL-1.8. Electromagnetic fields attenuated the presence of mast cells and macrophages in tissues surrounding SPCL and magSPCL-1.8, between weeks 1 and 9. Macrophage reduction was more pronounced for magSPCL-1.8, which could explain why this material prevented growth of fibrous tissue overtime. CONCLUSION Magnetically actuated biomaterials have potential to modulate inflammation and the growth of fibrous tissue.

The functionalization of natural polymer-coated gold nanoparticles to carry bFGF to promote tissue regeneration

Gold nanoparticles (AuNPs) enable the treatment and real-time monitoring of several diseases, providing an exciting and advantageous nanomedicine strategy. These NPs have therefore been adequately functionalized to enable them to carry growth factors (GF), namely basic fibroblastic (bF) GF, which play an essential role in different and important cellular processes including cellular proliferation, survival, migration and differentiation. The AuNPs were coated with natural polymers, chitosan and heparin, to enhance their physicochemical properties such as suspension stability. The polyelectrolyte coating was monitored using a quartz crystal microbalance with dissipation, size and zeta-potential analysis. The natural polymer-coated AuNPs have a spherical shape and a positive surface charge due to chitosan amino groups, enabling their biofunctionalization with monoclonal antibodies to target specific biomolecules. Additionally, cellular assays with the chondrocyte cell line ATDC5 show that the NPs are cytocompatible at relevant concentrations. As a proof of concept of their potential application in tissue regeneration, the natural polymer-coated AuNPs were further functionalized with an antibody to selectively bind the desired GF. The bFGF concentration reached in the NPs without compromising the cytocompatibility demonstrates the potential of this carrier for tissue regeneration.