Uptake and toxicity of quantum dots in cancer cells

Most of the work on quantum dots has so far been focused on their production and fluorescence imaging. The possibility to use quantum dots as photosensitizers remains unexplored: Can these nanoparticles generate reactive oxygen species in biological envir onments? Such a potential of quantum dots will be studied with the ultimate aim for diagnostics and therapy. Two general limitations apply to most anticancer drugs and imaging agents: Low targeting selectivity, and inefficient passage through the biologic al barriers to the target. Nanotechnology is a rapidly developing multidisciplinary field covering a new generation of nanoscale particles for targeted delivery of anticancer drugs and imaging markers. However, synthesis of so-called quantum dots is far f rom being standardized, and many features are yet to be explored. The challenge is to improve the surface and the bioconjugation of these small probes, and to optimize them for successful applications in vivo. The possibility of using bioconjugated quantu m dots for biological applications and for animal imaging is exciting. However, data on the pharmacokinetics and toxicity in vivo are lacking. Before the benefits of targeting with quantum dots for imaging and treatment of cancer can be realized in clinic al use, more information about their properties must be gathered.