Sintering effects of mullite-doping on mechanical properties of bovine hydroxyapatite.

In this study, sintering effects on microstructural behavior of bovine derived hydroxyapatite doped with powder mullite are considered in the temperature range between 1000°C and 1300°C. Results show that maximum values of both compressive strength and microhardness are achieved in the samples sintered at 1200°C for all mullite additions of 5, 7.5, 10 and 12.5wt%. Moreover, above 1000°C, decomposition of HA and new phase formations such as whitlockite and gehlenite play a major role in both compressive strength and microhardness properties which increase up to 10wt% mullite reinforcement.

Fabrication of magnetite-based core-shell coated nanoparticles with antibacterial properties.

We report the fabrication of biofunctionalized magnetite core/sodium lauryl sulfate shell/antibiotic adsorption-shell nanoparticles assembled thin coatings by matrix assisted pulsed laser evaporation for antibacterial drug-targeted delivery. Magnetite nanoparticles have been synthesized and subsequently characterized by transmission electron microscopy and x-ray diffraction. The obtained thin coatings have been investigated by FTIR and scanning electron microscope, and tested by in vitro biological assays, for their influence on in vitro bacterial biofilm development and cytotoxicity on human epidermoid carcinoma (HEp2) cells.

Usnic acid-loaded biocompatible magnetic PLGA-PVA microsphere thin films fabricated by MAPLE with increased resistance to staphylococcal colonization.

Due to their persistence and resistance to the current therapeutic approaches, Staphylococcus aureus biofilm-associated infections represent a major cause of morbidity and mortality in the hospital environment. Since (+)-usnic acid (UA), a secondary lichen metabolite, possesses antimicrobial activity against Gram-positive cocci, including S. aureus, the aim of this study was to load magnetic polylactic-co-glycolic acid-polyvinyl alcohol (PLGA-PVA) microspheres with UA, then to obtain thin coatings using matrix-assisted pulsed laser evaporation and to quantitatively assess the capacity of the bio-nano-active modified surface to control biofilm formation by S. aureus, using a culture-based assay. The UA-loaded microspheres inhibited both the initial attachment of S. aureus to the coated surfaces, as well as the development of mature biofilms. In vitro bioevalution tests performed on the fabricated thin films revealed great biocompatibility, which may endorse them as competitive candidates for the development of improved non-toxic surfaces resistant to S. aureus colonization and as scaffolds for stem cell cultivation and tissue engineering.