Characterization of spectrally distinct Aurelia-1 and Aurelia-2 gold
nanorods (GNRs). (A) Dynamic light scattering–based
distribution of Aurelia-1 (larger peak [LP], 101.4 ± 1.53 [SD];
polydispersity index [PDI], 0.82 ± 0.004) (smaller peak [SP],
3.06 ± 0.02; PDI, 0.82 ± 0.004). (B) Dynamic
light scattering–based distribution of Aurelia-2 (LP, 68.76
± 1.04; PDI, 0.82 ± 0.004) (SP, 1.06 ± 0.03; PDI,
0.82 ± 0.004). (C) Multispectral optoacoustic
tomography (MSOT)–based detection of Aurelia-1 (blue) and
Aurelia-2 (red) GNRs inside a tissue-mimicking phantom. (D,
E) MSOT identification of the near-infrared spectral shape of
Aurelia-1 (absorption peak at 780 nm) and Aurelia-2 (absorption peak at
720 nm). (F) MSOT detection of predefined blue (Aurelia-1)
and red (Aurelia-2) color from the mixture of 1 mg of both GNRs after
spectral unmixing. (G, H) Transmission electron microscopy
image findings determined GNR size and total Aurelia-1 and Aurelia-2
size. Aurelia-1 and Aurelia-2 GNR sizes were as follows: Aurelia-1
length: 44.9 nm ± 2.01, width: 35.75 nm ± 1.20; Aurelia-2
length: 21.21 nm ± 2.12, width: 9.13 nm ± 0.25. The total
particle sizes, including silica and chitosan, of Aurelia-1 and
Aurelia-2 were as follows: Aurelia-1 length: 50.5 nm ± 3.06,
width: 38.92 nm ± 0.87; Aurelia-2 length: 23.52 nm ± 2.09,
width: 10.23 nm ± 0.43. a.u. = arbitrary units.