传统光声成像外源对比剂的光吸收主要集中在可见光区和传统近红外区(NIR, 750~900 nm), 开发具有更高光学组织穿透能力的近红外二区(NIR-II, 1 000~1 700 nm)光吸收外源对比剂对活体深层组织光声成像具有重要意义。本文中, 作者选取了光吸收峰在1 000 nm左右的半导体型单壁碳纳米管为近红外二区光学吸收外源对比剂, 测试了其在近红外二区激光激发下能够产生较强的光声效应。进一步地, 作者通过将该纳米材料包埋在仿体组织的不同深度的位置, 获得了仿体组织的深层光声成像, 成像深度可达1.5 cm。试验结果表明, 具有近红外二区光吸收能力的半导体型单壁碳纳米管在活体深层组织光声成像中有很大的应用潜力。

The optical absorption of exogenous contrast agents in conventional photoacoustic imaging is mainly concentrated in the visible region and the traditional near infrared region (NIR, 750~900 nm). The development of near-infrared-II (NIR-II, 1 000~1 700 nm) nanoprobes with higher optical tissue penetration depth is of great significance for photoacoustic imaging of deep tissue in vivo. In this paper, semiconductor single-walled carbon nanotubes with optical absorption peaks of about 1 000 nm were selected as the exogenous contrast agent for near-infrared-Ⅱphotoacoustic imaging. The strong photoacoustic effect was tested under near-infrared-Ⅱlaser excitation. Furthermore, the deep photoacoustic imaging of the phantom tissue was obtained by embedding the nanomaterial in different depths of the tissue-mimic phantom. The imaging depth can reach 1.5 cm. Experimental results show that semiconductor single-walled carbon nanotubes (SWCNTs) with near-infrared-Ⅱ optical absorption have great potential in photoacoustic imaging of deep tissues in vivo.