The miniaturization of gold nanorods exhibits a bright prospect for intravital photoacoustic imaging (PAI) and the hollow structure possesses a better plasmonic property. Herein, miniature hollow gold nanorods (M‐AuHNRs) (≈46 nm in length) possessing strong plasmonic absorbance in the second near‐infrared (NIR‐II) window (1000–1350 nm) are developed, which are considered as the most suitable range for the intravital PAI. The as‐prepared M‐AuHNRs exhibit 3.5 times stronger photoacoustic signal intensity than the large hollow Au nanorods (≈105 nm in length) at 0.2 optical density under 1064 nm laser irradiation. The in vivo biodistribution measurement shows that the accumulation in tumor of miniature nanorods is twofold as high as that of the large counterpart. After modifying with a tumor‐targeting molecule and fluorochrome, in living tumor‐bearing mice, the M‐AuHNRs group gives a high fluorescence intensity in tumors, which is 3.6‐fold that of the large ones with the same functionalization. Moreover, in the intravital PAI of living tumor‐bearing mice, the M‐AuHNRs generate longer‐lasting and stronger photoacoustic signal than the large counterpart in the NIR‐II window. Overall, this study presents the fabrication of M‐AuHNRs as a promising contrast agent for intravital PAI.

中文翻译：

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具有增强效果的微型空心金纳米棒，用于在NIR-II窗口中进行体内光声成像。

金纳米棒的小型化为活体内光声成像（PAI）展示了广阔的前景，中空结构具有更好的等离子体性能。本文中，开发了在第二个近红外（NIR-II）窗口（1000-1350 nm）中具有强等离子体吸收性的微型空心金纳米棒（M-AuHNRs）（长度约46 nm）。 PAI的范围。在1064 nm激光辐照下，所制备的M-AuHNR在0.2光密度下的光声信号强度比大型中空Au纳米棒（长度约105 nm）强3.5倍。体内生物分布测量表明，微型纳米棒在肿瘤中的积累是大型纳米棒的两倍。用肿瘤靶向分子和荧光染料修饰后，在活着的荷瘤小鼠中，M-AuHNRs组在肿瘤中具有很高的荧光强度，是具有相同功能的大肿瘤的3.6倍。此外，在活体荷瘤小鼠的活体内PAI中，M-AuHNR比NIR-II窗口中的大型对应物产生更持久和更强的光声信号。总的来说，这项研究提出了将M-AuHNRs用作活体PAI的有希望的造影剂。