Differential effects of nanoselenium doping on healthy and cancerous osteoblasts in coculture on titanium.

In the present study, selenium (Se) nanoclusters were grown through heterogeneous nucleation on titanium (Ti) surfaces, a common orthopedic implant material. Normal healthy osteoblasts (bone-forming cells) and cancerous osteoblasts (osteosarcoma) were cultured on the Se-doped surfaces having three different coating densities. For the first time, it is shown that substrates with Se nanoclusters promote normal osteoblast proliferation and inhibit cancerous osteoblast growth in both separate (mono-culture) and coculture experiment. This study suggests that Se surface nanoclusters can be properly engineered to inhibit bone cancer growth while simultaneously promoting the growth of normal bone tissue.

Titanium surfaces with adherent selenium nanoclusters as a novel anticancer orthopedic material.

Current orthopedic implants have several problems that include poor osseointegration for extended periods of time, stress shielding and wear debris-associated bone cell death. In addition, numerous patients receive orthopedic implants as a result of bone cancer resection, yet current orthopedic materials were not designed to prevent either the occurrence or reoccurrence of cancer. The objective of this in vitro study was to create a new biomaterial which can both restore bone and prevent cancer growth at the implant-tissue interface. Elemental selenium was chosen as the biologically active agent in this study because of its known chemopreventive and chemotherapeutic properties. It was found that when selenite salts were reduced by glutathione in the presence of an immersed titanium substrate, elemental selenium nucleated and grew into adherent, hemispherical nanoclusters that formed a nanostructured composite surface. Three types of surfaces with different selenium surface densities on titanium were fabricated and confirmed by SEM images, AFM, and XPS profiles. Compared to conventional untreated titanium, a high-density selenium-doped surface inhibited cancerous bone cell proliferation while promoting healthy bone cell functions (including adhesion, proliferation, alkaline phosphatase activity and calcium deposition). These findings showed for the first time the potential of selenium nanoclusters as a chemopreventive titanium orthopedic material coating that can also promote healthy bone cell functions.

A nano-selenium reactive barrier approach for managing mercury over the life-cycle of compact fluorescent lamps.

Compact fluorescent lamps contain small quantities of mercury, release of which can lead to human exposures of potential concern in special cases involving multiple lamps, confined spaces, or young children. The exposure scenarios typically involve solid lamp debris that slowly releases elemental mercury vapor to indoor spaces. Here we propose and demonstrate a reactive barrier approach for the suppression of that mercury release, and demonstrate the concept using uncoated amorphous nanoselenium as the reactive component. Multilayer structures containing an impregnated reactive layer and a mercury vapor barrier are fabricated, characterized, and evaluated in three exposure prevention scenarios: carpeted break sites, disposal/recycling bags, and boxes as used for retail sales, shipping, and collection. The reactive barriers achieve significant suppression of mercury release to indoor spaces in each of thethree scenarios. The nanoselenium barriers also exhibit a unique indicator function that can reveal the location of Hg contamination by local reaction-induced change in optical properties. The article also presents results on equilibrium Hg vapor pressure above lamp debris, mathematical modeling of reaction and transport processes within reactive barriers, and landfill stability of nanoselenium and its reaction products.