Silver Nanoparticles Monitored in Vivo

Silver nanoparticles passively diffuse into zebrafish embryos through their external pores, according to a study designed to explore nanoparticles' potential as imaging and therapeutic agents (ACS Nano 2007, 1, 133). Xiao-Hong Nancy Xu and coworkers at Old Dominion University utilized the nanoparticles as probes to observe their transport into the embryos, which are small, inexpensive, and well-suited for whole-animal studies. The team made measurements by using an optical microscopy technique recently developed in Xu's lab. The technology exploits silver nanoparticles' inherent brightness and color to measure individual nanoparticle sizes and trace nanoparticle movement. The researchers also monitored the nanoparticles' toxicity, discovering that a dose-dependent toxicity exists, even at subnanomolar concentrations. This toxicity may be due to nanoparticle aggregation within the pores, Xu says. Her team plans to continue using zebrafish for in vivo nanoparticle studies and to pin down which properties influence toxicity.