Fig. 3

In vitro PA and US imaging of GNRs@PEG-Iso4. A Representative 2D PA and US image of capillary tubes filled with the indicated amount of GNRs@PEG-Iso4 (upper), and quantification of PA signal (lower). Grayscale, co-registered US signal; Green, PA signal of NPs. Bar, 1 mm. B Representative 2D and 3D PA and US images (upper and middle panels, respectively) of an agar drop with or without GNRs@PEG-Iso4 (30 µl nanogold, 30 nmol Au, ~ 1.16 × 10¹¹ NPs), and quantification of PA signal (lower). The yellow dotted line in the upper marks the boundary between agar drop and the slime gel. Grayscale, co-registered US signal; Green: PA signal. Bar, 1 mm. Note that GNRs accumulated mainly at the periphery of the drop during the polymerization of the agar/GNRs mixture