Impact of single-walled carbon nanotubes on the embryo: a brief review.

Carbon nanotubes (CNTs) are considered one of the most interesting materials in the 21st century due to their unique physiochemical characteristics and applicability to various industrial products and medical applications. However, in the last few years, questions have been raised regarding the potential toxicity of CNTs to humans and the environment; it is believed that the physiochemical characteristics of these materials are key determinants of CNT interaction with living cells and hence determine their toxicity in humans and other organisms as well as their embryos. Thus, several recent studies, including ours, pointed out that CNTs have cytotoxic effects on human and animal cells, which occur via the alteration of key regulator genes of cell proliferation, apoptosis, survival, cell-cell adhesion, and angiogenesis. Meanwhile, few investigations revealed that CNTs could also be harmful to the normal development of the embryo. In this review, we will discuss the toxic role of single-walled CNTs in the embryo, which was recently explored by several groups including ours.

Significant toxic role for single-walled carbon nanotubes during normal embryogenesis.

In order to investigate the effect of SWCNTs in the embryo, we examined the outcome of SWCNTs in avian embryo at an early stage of development. We found that SWCNTs-treatment inhibits the angiogenesis of the chorioallantoic membrane (CAM) and in the chicken embryo. Moreover, we showed that SWCNTs can harm the normal development of the embryo since all SWCNTs-exposed embryos are smaller in comparison with their matched controls. We also found that the majority of SWCNTs-exposed embryos die before 12days of incubation. Macroscopic examination did not reveal any anomalies in these embryos. However, RT-PCR analysis of eleven genes, which are important regulators of cell proliferation, apoptosis, survival and angiogenesis, shows that these genes are deregulated in brain and liver tissues from SWCNTs-treated embryos in comparison with their matched controls. This study suggests that SWCNTs could have a very toxic effect on the normal development of the embryo. FROM THE CLINICAL EDITOR: In this study, a significant toxicity of single-walled carbon nanotubes was observed during normal embryogenesis: the nanotubes inhibited the angiogenesis of the chorioallantoic membrane (CAM) in chicken embryos. All exposed embryos died before 12 days of incubation, suggesting a severe effect.

Analytical solutions and validation of electric field and dielectrophoretic force in a bio-microfluidic channel.

In a microbiological device, cell or particle manipulation and characterization require the use of electric field on different electrodes in several configurations and shapes. To efficiently design microelectrodes within a microfluidic channel for dielectrophoresis focusing, manipulation and characterization of cells, the designer will seek the exact distribution of the electric potential, electric field and hence dielectrophoresis force exerted on the cell within the microdevice. In this paper we describe the approach attaining the analytical solution of the dielectrophoretic force expression within a microchannel with parallel facing same size electrodes present on the two faces of channel substrates, with opposite voltages on the pair electrodes. Simple Fourier series mathematical expressions are derived for electric potential, electric field and dielectric force between two distant finite-size electrodes. Excellent agreement is found by comparing the analytical results calculated using MATLAB™ with numerical ones obtained by Comsol. This analytical result can help the designer to perform simple design parametric analysis. Bio-microdevices are also designed and fabricated to illustrate the theoretical solution results with the experimental data. Experiments with red blood cells show the dielectrophoretic force contour plots of the analytical data matched to the experimental results.