Physical and in vitro biological evaluation of a PA 6/MWCNT electrospun composite for biomedical applications

Significant progress in the study of scaffolds for cell growth has taken place that has led to the development of a wide variety of metallic, polymeric, ceramic, and composite biomaterials. This article describes the fabrication and characterization of an electrospun net with tunable morphological and mechanical properties composed by aligned fibers of polyamide 6 (PA 6) and carboxyl-functionalized multi-walled carbon nanotubes (MWCNT). Physical and short-term biological properties of the nets were evaluated, focusing on the effect of the filler addition. The production technique used, induced the alignment of MWCNT within the nanofiber axis and the formation of a roughness on the fiber's surface. The proliferation and activation of MG63 cell line osteoblasts were enhanced due to surface modification caused by the filler addition compared to the purely PA 6 networks.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.2613547'Provincia Autonoma di Trento' (PAT

Effects of cardiomyopathic mutations on the biochemical and biophysical properties of the human alpha-tropomyosin

Mutations in the protein alpha-tropomyosin (Tm) can cause a disease known as familial hypertrophic cardiomyopathy. In order to understand how such mutations lead to protein dysfunction, three point mutations were introduced into cDNA encoding the human skeletal tropomyosin, and the recombinant Tms were produced at high levels in the yeast Pichia pastoris. Two mutations (A63V and K70T) were located in the N-terminal region of Tm and one (E180G) was located close to the calcium-dependent troponin T binding domain. The functional and structural properties of the mutant Tms were compared to those of the wild type protein. None of the mutations altered the head-to-tail polymerization, although slightly higher actin binding was observed in the mutant Tm K70T, as demonstrated in a cosedimentation assay. The mutations also did not change the cooperativity of the thin filament activation by increasing the concentrations of Ca2+. However, in the absence of troponin, all mutant Tms were less effective than the wild type in regulating the actomyosin subfragment 1 Mg2+ ATPase activity. Circular dichroism spectroscopy revealed no differences in the secondary structure of the Tms. However, the thermally induced unfolding, as monitored by circular dichroism or differential scanning calorimetry, demonstrated that the mutants were less stable than the wild type. These results indicate that the main effect of the mutations is related to the overall stability of Tm as a whole, and that the mutations have only minor effects on the cooperative interactions among proteins that constitute the thin filament

Scaffolds of poly (epsilon-caprolactone) with whiskers of hydroxyapatite

Scaffolds of Poly (epsilon-caprolactone)/hydroxyapatite were produced and studied for tissue engineering applications. The materials were selected due to its biodegradability (PCL) and bioactivity (HA), and above all their biocompatibility toward the human tissue. The composites produced were characterized by SEM, XRD, and EDS. By analyzing these characterizations it was possible to obtain further information about the composition and morphology aspects of all portions of the composite scaffold.45184990499