No abstract

No abstract

Surface modification techniques based on the grafting of chemical functional groups and immobilization of bioactive molecules have been used to improve biocompatibility and clinical performance of bioabsorbable scaffolds in tissue engineering and medicine regenerative applications. This study aimed at developing and characterizing a biomimetic surface to stimulate bone regeneration by a simple and low-cost method of surface biofunctionalization of the poly (L-co-D,L lactic acid)-PLDLA scaffolds. The method was obtained by grafting reaction of carboxyl groups (-COOH) on their surface via acrylic acid (AAc) polymerization process, followed by immobilization of collagen type I (Col). Such approach resulted in a surface morphology markedly modified after treatment, with increase of pores and roughness on PLDLA-AAc surfaces and a network of fibrillar collagen deposition in nonspecific areas of PLDLA-Col surfaces. The cytocompatibility of collagen-immobilized scaffolds was significantly improved in terms of cellular adhesion, proliferation, collagen synthesis and maintenance of osteoblast-like phenotype, indicating, therefore, the fundamental role of collagen protein over the biological interactions that occur by bio-recognition mimetic mechanisms at biomaterials interface. These results indicate that the surface modification method used here may be useful as a strategy to develop biofunctional scaffolds, which provide a more successful clinical application of biomaterials in the tissue engineering field.

No abstract

The present study reports the deposition of coating using Plasma Electrolytic Oxidation (PEO) onto grade 4 titanium to produce novel surface features. Samples were treated in an electrolytic solution of calcium acetate and sodium glycerolphosphate. The temporal evolution of hydroxyapatite coatings with high Ra roughness and a maximum thickness of 120 µm was obtained. X-ray spectra revealed the presence of hydroxyapatite, rutile and calcium phosphate. Cell growth measurement by MTT assay showed that the coatings were not toxic because cells grew on all samples.

Poly(ε-caprolactone) (PCL) is an aliphatic polyester widely explored in the preparation of guided bone regeneration (GBR) membranes because of its interesting mechanical properties and biodegradability. However, PCL high hydrophobicity often impairs cell adhesion and proliferation as well as calcium phosphate growth, all of which are crucial to achieving suitable bone-tissue integration. In this work, aimed at achieving less-hydrophobic surfaces, amphiphilic molecules were added at low concentrations to the polymeric dope solutions that generated the GBR membranes. During membrane formation, these molecules migrate to the solution/air interface in such a way that, upon liquid-solid phase transition, the negatively charged heads are exposed while the apolar tails are anchored to the polymer bulk. As a consequence, these molecules became nucleating agents for subsequent calcium phosphate growth using an alternating soaking process. Herein, PCL porous membranes containing different amphiphilic molecules, such as stearic acid and bis(2-ethylhexyl) phosphate, were investigated. This new, simple, and atoxic method to superficially treat polymeric membranes could be extended to a wide range of polymers and applications.

No abstract

No abstract