Near-Infrared Silica-Based Gold Nanoshells as Potential Rapid Diagnostic Imaging Agents For Breast Cancer Tumor Detection

摘要

Although much research has focused on using near-infrared silica-based goldnanoshells for dual-imaging and therapeutic applications in vivo, these particles may alsoprove useful as rapid diagnostic imaging agents for ex vivo applications, such asintraoperative tumor margin detection. In this thesis, gold nanoshells were successfullydesigned to target breast cancer cells through antibodies against the extracellular HumanEpidermal growth factor Receptor 2 (HER2) , whose overexpression is associated withmore aggressive forms of breast cancer. By comparing HER2-positive breast cancer cellsto normal (nonneoplastic) breast cells, the nanoshells effectively labeled HER2-overexpression within 5 minutes of incubation time. These nanoshells also enhanced contrast of the same cancer cells using two-photon microscopy, which enabledsubsequent validation of preferential labeling using a distinctive co-culture experiment.To ultimately translate these findings to the clinic, nanoshells of similar designwere studied for their effectiveness at enhancing contrast of malignancy in breast tissuesections and intact human breast tissue. Through detailed experimental conditions, thesenanoshells increased contrast of cancer cells in sectioned HER2-overexpressing breasttissue within 5 minutes of incubation time using reflectance confocal microscopy, aunique imaging capability not previously reported. Finally, these targeted nanoshellsiiwere used to effectively visualize HER2 receptor expression in intact human breast tissuespecimens within the same 5 minute incubation time point. Through two-photon imaging,it was shown that these nanoparticies preferentially labeled tissue surface receptors, withminimal penetration depth. Importantly, the enhanced surface labeling was observedmacroscopically through a standard stereomicroscope and confirmed microscopicallythrough reflectance confocal microscopy and immunohistochemistry. These resultssuggest that anti-HER2-nanoshells used in tandem with a near-infrared reflectanceconfocal microscope and a standard stereomicroscope may potentially be used to discernHER2-overexpressing cancerous tissue from normal tissue in near real time and offer arapid supplement to current diagnostic techniques.111were used to effectively visualize HER2 receptor expression in intact human breast tissuespecimens within the same 5 minute incubation time point. Through two-photon imaging,it was shown that these nanoparticles preferentially labeled tissue surface receptors, withminimal penetration depth. Importantly, the enhanced surface labeling was observedmacroscopically through a standard stereomicroscope and confirmed microscopicallythrough reflectance confocal microscopy and immunohistochemistry. These resultssuggest that anti-HER2-nanoshells used in tandem with a near-infrared reflectanceconfocal microscope and a standard stereomicroscope may potentially be used to discernHER2-overexpressing cancerous tissue from normal tissue in near real time and offer arapid supplement to current diagnostic techniques.iii