Inhibition of Embryonic Stem Cell Differentiation by Gold Nanoparticles

Nanomaterials are attractive for use in technological advancements because of their small size and unique properties. As a result, there has been a rapid increase in the production and applications of nanomaterials. Nanoparticles like carbon, cadmium and silver are highly toxic and are known to cause oxidative stress. However, there are conflicting reports regarding the toxicity of gold nanoparticles. We have investigated the effects of gold nanoparticles on the growth and differentiation of ESCs (embryonic stem cells). Analysis of ESCs treated with gold nanoparticles revealed a biphasic growth response. Higher concentrations (> 20 μg/mL) of gold nanoparticles inhibited growth, whereas the lower concentrations (< 10 μg/mL) stimulated ESC proliferation. Interestingly, ESC pluripotency was not affected by gold nanoparticles as demonstrated by the near normal expression of the specific pluripotent marker, Oct 4, and their differentiation potential. Inhibition of differentiation of both ESCs and embryoid bodies by gold nanoparticles suggest that they may pose developmental risks. Further analysis by transmission electron microscopy and atomic absorption spectroscopy revealed that gold nanoparticles were actively taken up by ESCs in a concentration dependent manner. These observations suggest that exposure to gold nanoparticles may cause embryotoxicity or effect early childhood development.