Current treatments for brain aneurysms are invasive, traumatic, and not suitable in most patients with increased risks. A new alternative method is using scaffold stents to create a local and focal attraction force of cells for an in situ reconstruction of the tunica media. For this purpose, a nanostructured bioactive coating is designed to render an asymmetric region of the stent scaffold magnetic and biomimetic, which utilizes bacterial nanocellulose (BNC) as a platform for both magnetic and cell attraction as well as proliferation. The magnetization of the BNC is realized through the reaction of Fe III and II, precipitating superparamagnetic iron oxide nanoparticles (SPION). Subsequently, magnetic bacterial nanocellulose (MBNC) is coated with polyethylene glycol to improve its biocompatibility. Cytotoxicity and biocompatibility are evaluated using porcine aortic smooth muscle cells. Preliminary cellular migration assays demonstrate the behavior between MBNC and cells labeled with SPION. In this work, (1) synthesis of BNC impregnated with magnetic nanoparticles is successfully demonstrated; (2) a viable, resilient, and biocompatible hydrogel membrane is tested for neuroendovascular application using a stent scaffold; (3) cell viability and minimal cytotoxicity is achieved; (4) cell migration tests and examination of cellular magnetic attraction confirm the viability of MBNC as a multifunctional coating.
Titanium (Ti) is a material frequently used in orthopedic applications, due to its good mechanical properties and high corrosion resistance. However, formation of a non-adherent fibrous tissue between material and bone drastically could affect the osseointegration process and, therefore, the mechanical stability of the implant. Modifications of topography and configuration of the tissue/ material interface is one of the mechanisms to improve that process by manipulating parameters such as morphology and roughness. There are different techniques that can be used to modify the titanium surface; plasma electrolytic oxidation (PEO) is one of those alternatives, which consists of obtaining porous anodic coatings by controlling parameters such as voltage, current, anodizing solution and time of the reaction. From all of the above factors, and based on previous studies that demonstrated that bone cells sense substrates features to grow new tissue, in this work commercially pure Ti (c.p Ti) and Ti6Al4V alloy samples were modified at their surface by PEO in different anodizing solutions composed of H2SO4 and H3PO4 mixtures. Treated surfaces were characterized and used as platforms to grow osteoblasts; subsequently, cell behavior parameters like adhesion, proliferation and differentiation were also studied. Although the results showed no significant differences in proliferation, differentiation and cell biological activity, overall results showed an important influence of topography of the modified surfaces compared with polished untreated surfaces. Finally, this study offers an alternative protocol to modify surfaces of Ti and their alloys in a controlled and reproducible way in which biocompatibility of the material is not compromised and osseointegration would be improved.
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