Fig. 10

Imaging of cancer with microscopic precision using SERS nanoparticles. A Schematic synthesis process of GERTs, including (i) Au cores, (ii) 4-nitrobenzenethiol (4-NBT) modified Au cores, (iii) gap-enhanced Raman tags with a petal-like shell (P-GERTs), (iv) IR-780 modified P-GERTs and (v) GERTs. [207] B MPRs are injected intravenously into a mouse bearing an orthotopic brain tumor. As the nanoparticles circulate in the bloodstream, they diffuse through the disrupted blood–brain barrier and are then sequestered and retained by the tumor. The MPRs are too large to cross the intact blood–brain barrier and, therefore, cannot accumulate in healthy brain. [215] C SERS image of resection bed was acquired after surgical excision of tumor bulk (left). Resection was guided by white light only, with surgeon blinded to SERS images. Immunohistochemistry staining for human vimentin confirmed that SERS-positive signal (arrows 1 and 2) represented microscopic residual cancer at margins of resection bed (middle). Immunohistochemistry images on right are magnified views of areas indicated with arrows 1 and 2. D SERS image of locoregional tumor micrometastases. The multiple small foci of Raman signal (arrows 1 to 5) were found approximately 10 mm away from the margins of the bulk tumor. As confirmed by immunohistochemistry (middle), each of these 5 foci correlated with a separate tumor cluster (vimentin +) as small as 100 \(\mu m\) (micrometastases). Images on far right are magnified views of the metastases labeled 4 and 5. [216] A reprinted with permission from Ref. 207,