Silk Fibroin/Calcium Phosphate Silicate Composites: In vitro Bioactivity

Abstract Co mposite materials of Silk Fib roin (SF) and Calciu m Phosphate Silicate (CPS) ceramic in the 15CaO-6SiO 2 -0.5P 2 O 5 system were prepared by method of mixing d ifferent percentage of component weight. The structure was characterized before and after in vitro test by FTIR, SEM. The concentration of Ca, Si and P after in vit ro test was analysed by ICP-A ES. FTIR of the composites before in vitro test depicts that random coil and β-sheet structures co-exist in the co mposites. CPS ceramic has a significant effect on the secondary structure of SF. SEM observed that CPS particles uniformly dispersed in SF matrix. FTIR of the composites after in vitro test revealed that carbonate containing hydroxyapatite (CO 3 HA) was formed on the surface. B-type CO 3 HA preferentially formed in the samp le with 75 wt. % CPS ceramic. SEM proved that hydroxyapatite (HA) fo rmed in a high level. ICP-A ES showed that HA precipitation were similar fo r the three composites. Based of these results, it can be concluded that the incorporation of CPS ceramic powder enhanced the in vitro bioactivity

Elastic-Plastic Properties of hard Cr-Based Nitride Coatings Deposited at Temperatures Below 200°C

Sets of Cr-based hard coatings were prepared via reactive closed field unbalanced magnetron sputtering (CFUBMS). Substrate temperature was kept in range of 150 to 200°C during deposition. Nanohardness (H) and effective modulus of elasticity (E*) of the coatings were examined, using depth-sensing indentation method. In order to present the mechanical properties and predict the tribological behaviour of the prepared coatings ratios H/E* (elasticity index), H3/E*2 (resistance to plastic deformation) and 1/(HE*2) (resistance to crack formation) were calculated and analysed. The results from the combined examination of the research ratios showed that they could be used for classification of the expected wear-resistant properties of Cr-based hard coatings deposited at temperature below 200°C

In vitro Bioactivity of Polycaprolactone/Bioglass Composites

A series of Polycaprolactone and Bioglass in the 85SiO 2-10CaO-5P2O 5 (mol. %) systems were synthesized at different quantity of the organic/inorganic co mponents. The 85S Bioglass was prepared via sol-gel method. It was added to the Polycaprolactone matrix at 20, 50 and 80 weight (wt.) %, respectively. In vitro bioactivity of the prepared composites was evaluated in 1.5 Simu lated Body Flu id (1.5 SBF). The obtained composite materials before and after static in vitro test were characterized by FTIR and SEM. The obtained experimental data proved that the synthesized co mposites exhibit good in vitro bioactivity. After immersion in 1.5SBF, SEM depicts the presence of nano-needle-like hydro xyapatite on the immersed 20PCL/80BG and 50PCL/50BG samples