Figure 4

Photothermal treatment of MCF-7 tumors. (a) Photographs of typical tumors removed from mice 20 days after photothermal therapy (for the target-AuNRs group, two of the tumors disappeared completely); (b) average tumor volume before and 20 days after the treatment; (c) images of HE stained sections of tumors obtained 3 h after 808 nm laser treatment. Target-AuNRs, AuNRs modified with peptide 1; PEG-AuNRs, PEG-modified AuNRs; Control-AuNRs, AuNRs modified with a control peptide; Saline, saline only and without AuNRs. Compared with the normal nucleus of cancer cells in the control tumor, contiguous cell necrosis is determined by the extensive pale eosinophilic cytoplasm (typically highlighted by dashed ovals), as well as karyolysis and nuclear swelling (typically highlighted by solid ovals). Cell apoptosis with the presence of nuclear pyknosis, hepereosinophilic cytoplasm (typically highlighted by arrows) and apoptotic bodies (typically highlighted by arrow heads) is marked. The normal tumor tissue area in each AuNRs treated group is also circled with angled dashed frames.