Extended Data Fig. 7: In vivo SERS imaging by NBT@Au GERTs.

a,b, SERS imaging (1340 cm⁻¹) merged with photographs of ALNs after 15 min of the intradermal injection with NBT@Au GERTs (80 μg of Au) in the left front paw of mice. Yellow arrow, the injection site. White arrows, ALNs. Raman imaging was performed before (a) and after (b) removing the skin, respectively. c, Raman spectra of sites 1 or 2 in (a) or (b). d, SERS imaging (1340 cm⁻¹) of the resected ALN following the imaging experiment in (b). e, H&E staining (8-μm thickness) and Raman imaging (50-μm thickness) analysis of the adjacent sections of ALN in (d), respectively. Image shown is representative of n = 3 independent replicates of experiments with similar results. f, Raman spectra of the sites in (d) and (e), respectively. Orange columns, peaks at 1340 cm⁻¹. g, SERS imaging (1340 cm⁻¹) of mouse abdominal subcutaneous blood vessels following i.v. injection of NBT@Au GERTs (40 mg kg⁻¹ of Au). Blue boxed image, the enlarged area. h, The vertically flipped image of the photographs of the resected abdominal skin with the subcutaneous blood vessels facing up, after the Raman imaging in (g) and euthanasia. i, Raman spectra of different sites in (g). Orange column, peaks at 1340 cm⁻¹. j, FWHM analysis of blood vessels along the blue dotted line in (g). Black line, the cross-sectional intensity profile (1340 cm⁻¹) of the blood vessel. Red line, the Gaussian fitting curve. k, Raman imaging (1340 cm⁻¹) of blood vessels in leg of mice following i.v. injection of NBT@Au GERTs (40 mg kg⁻¹ of Au). Arrow, microvessels. Asterisks, the regions of hindlimb without distinguishable signals of microvessels. l, Raman spectra of different sites in (k). Orange column, peaks at 1340 cm⁻¹. m, FWHM analysis of micro-blood vessels along the blue dotted line in (k). Black line, the cross-sectional intensity profile (1340 cm⁻¹) of the blood vessels. Red line, the Gaussian fitting curve. Raman measurement was carried out with a 5 × objective, 830-nm laser excitation, a laser power of 62.6 mW, acquisition time of 0.3 s and one time accumulation (a,b,d,g,k) or 1 s in (e), and one time accumulation.