Trojan-like internalization of anatase titanium dioxide nanoparticles by human osteoblast cells

Dentistry and orthopedics are undergoing a revolution in order to provide more reliable, comfortable and long-lasting implants to patients. Titanium (Ti) and titanium alloys have been used in dental implants and total hip arthroplasty due to their excellent biocompatibility. However, Ti-based implants in human body suffer surface degradation (corrosion and wear) resulting in the release of metallic ions and solid wear debris (mainly titanium dioxide) leading to peri-implant inflammatory reactions. Unfortunately, our current understanding of the biological interactions with titanium dioxide nanoparticles is still very limited. Taking this into consideration, this study focuses on the internalization of titanium dioxide nanoparticles on primary bone cells, exploring the events occurring at the nano-bio interface. For the first time, we report the selective binding of calcium (Ca), phosphorous (P) and proteins from cell culture medium to anatase nanoparticles that are extremely important for nanoparticle internalization and bone cells survival. In the intricate biological environment, anatase nanoparticles form bio-complexes (mixture of proteins and ions) which act as a kind of ‘Trojan-horse’ internalization by cells. Furthermore, anatase nanoparticles-induced modifications on cell behavior (viability and internalization) could be understand in detail. The results presented in this report can inspire new strategies for the use of titanium dioxide nanoparticles in several regeneration therapies

Stabilizing metastable tetragonal HfO \u3c inf\u3e 2 using a non-hydrolytic solution-phase route: Ligand exchange as a means of controlling particle size

This journal is © 2016 The Royal Society of Chemistry. There has been intense interest in stabilizing the tetragonal phase of HfO2 since it is predicted to outperform the thermodynamically stable lower-symmetry monoclinic phase for almost every application where HfO2 has found use by dint of its higher dielectric constant, bandgap, and hardness. However, the monoclinic phase is much more thermodynamically stable and the tetragonal phase of HfO2 is generally accessible only at temperatures above 1720 °C. Classical models comparing the competing influences of bulk free energy and specific surface energy predict that the tetragonal phase of HfO2 ought to be stable at ultra-small dimensions below 4 nm; however, these size regimes have been difficult to access in the absence of synthetic methods that yield well-defined and monodisperse nanocrystals with precise control over size. In this work, we have developed a modified non-hydrolytic condensation method to precisely control the size of HfO2 nanocrystals with low concentrations of dopants by suppressing the kinetics of particle growth by cross-condensation with less-reactive precursors. This synthetic method enables us to stabilize tetragonal HfO2 while evaluating ideas for critical size at which surface energy considerations surpass the bulk free energy stabilization. The phase assignment has been verified by atomic resolution high angle annular dark field images acquired for individual nanocrystals

Evaluation of Lipid Content in Microalgae Biomass Using Palm Oil Mill Effluent (Pome)

The scope of this study is to assess the main component of palm oil mill effluent (POME) to be used as organic carbon for microalgae. The applicable parameters such as optical density, chlorophyll content, mixed liquor suspended solid, mixed liquor volatile suspended solid, cell dry weight (CDW), carbon:total nitrogen ratio and growth rate were also investigated in this study. The characteristics and morphological features of the isolates showed similarity with Chlorella. Chlorella pyrenoidosa (CP) was found to be a dominant species in POME and Chlorella vulgaris (CV) could grow well in POME. Furthermore, the optimal lipid production was obtained at the ratio 95:05 CDW with highest lipid production by CP compared to CV. At day 20, CDW for CV species was obtained at 193 mg/L and with lipid content at 56 mg/L. Finally, the concentration ratio at 50:50 showed a higher absorbance of chlorophyll a for both strains