TY - JOUR
T1 - Miniature gold nanorods for photoacoustic molecular imaging in the second near-infrared optical window
AU - Chen, Yun Sheng
AU - Zhao, Yang
AU - Yoon, Soon Joon
AU - Gambhir, Sanjiv Sam
AU - Emelianov, Stanislav
N1 - Funding Information:
This work was supported in part by grants from Breast Cancer Research Foundation under grant BCRF-16-043 and National Institutes of Health under grants CA158598 and CA149740 (to S.E.); and from NCI CCNE-T U54 CA199075, The Canary Foundation and The Sir Peter Michael Foundation (to S.S.G.). The authors acknowledge T.Stoyanova for providing the cells.
Publisher Copyright:
© 2019, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2019/5/1
Y1 - 2019/5/1
N2 - In photoacoustic imaging, the second near-infrared (NIR-II) window is where tissue generates the least background signal. However, the large size of the few available contrast agents in this spectral range impedes their pharmacokinetics and decreases their thermal stability, leading to unreliable photoacoustic imaging. Here, we report the synthesis of miniaturized gold nanorods absorbing in the NIR-II that are 5–11 times smaller than regular-sized gold nanorods with a similar aspect ratio. Under nanosecond pulsed laser illumination, small nanorods are about 3 times more thermally stable and generate 3.5 times stronger photoacoustic signal than their absorption-matched larger counterparts. These unexpected findings are confirmed using theoretical and numerical analysis, showing that photoacoustic signal is not only proportional to the optical absorption of the nanoparticle solution but also to the surface-to-volume ratio of the nanoparticles. In living tumour-bearing mice, these small targeted nanorods display a 30% improvement in efficiency of agent delivery to tumours and generate 4.5 times greater photoacoustic contrast.
AB - In photoacoustic imaging, the second near-infrared (NIR-II) window is where tissue generates the least background signal. However, the large size of the few available contrast agents in this spectral range impedes their pharmacokinetics and decreases their thermal stability, leading to unreliable photoacoustic imaging. Here, we report the synthesis of miniaturized gold nanorods absorbing in the NIR-II that are 5–11 times smaller than regular-sized gold nanorods with a similar aspect ratio. Under nanosecond pulsed laser illumination, small nanorods are about 3 times more thermally stable and generate 3.5 times stronger photoacoustic signal than their absorption-matched larger counterparts. These unexpected findings are confirmed using theoretical and numerical analysis, showing that photoacoustic signal is not only proportional to the optical absorption of the nanoparticle solution but also to the surface-to-volume ratio of the nanoparticles. In living tumour-bearing mice, these small targeted nanorods display a 30% improvement in efficiency of agent delivery to tumours and generate 4.5 times greater photoacoustic contrast.
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U2 - 10.1038/s41565-019-0392-3
DO - 10.1038/s41565-019-0392-3
M3 - Article
C2 - 30833692
AN - SCOPUS:85062625856
SN - 1748-3387
VL - 14
SP - 465
EP - 472
JO - Nature Nanotechnology
JF - Nature Nanotechnology
IS - 5
ER -