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.

The evaluation of a semiautomated computer method to determine the effects of DMSO on Giardia lamblia-intestinal cell interaction.

In this work, we describe a semiautomated computer method to evaluate the activity of a common drug solvent, dimethyl sulfoxide (DMSO), on in vitro Giardia lamblia-host cell interaction. To compare the number of intestinal cells (IEC-6) and the adhered trophozoites over a specific area in control and treated coculture, a computer routine was created. Using video-light microscopy and digital image-processing tools, the operator was able to count the number of epithelial cells or parasites when they were still lying on the slide surface and without the need to detach them from the substrate for counting with a hemocytometer or other counting devices. Using this strategy, we calculated the total cell number per area and verified the effects of different concentrations of DMSO on G. lamblia-intestinal cell interaction and on the IEC-6 culture. At concentrations of 0.2% and 1%, this solvent produced a fragmentation on the monolayer of epithelial cells. However, DMSO did not affect the attachment of G. lamblia. In the course of these experiments, we compared the semiautomated method to the manual counting method and found that the first one generated smaller standard deviations (SD) than the second.