<i>In Vivo</i> Detection of Gold Nanoshells in Tumors Using Diffuse Optical Spectroscopy

This study demonstrates the use of diffuse optical spectroscopy (DOS) for the noninvasive measurement of gold nanoshell concentrations in tumors of live mice. We measured the diffuse optical spectra (500-800 nm) using an optical fiber probe placed in contact with the tissue surface. We performed <i>in vitro</i> studies on tissue phantoms illustrating an accurate measurement of gold-silica nanoshell concentration within 12.6% of the known concentration. <i>In vivo</i> studies were performed on a mouse xenograft tumor model. DOS spectra were measured at preinjection, immediately postinjection, 1 and 24 h postinjection times, and the nanoshell concentrations were verified using neutron activation analysis.