Photoacoustic imaging (PAI) in the second near-infrared region (NIR-II), due to deeper tissue penetration and a lower background interference, has attracted widespread concern. However, the development of NIR-II nanoprobes with a large molar extinction coefficient and a high photothermal conversion efficiency (PCE) for PAI and photothermal therapy (PTT) is still a big challenge. In this work, the NIR-II CuTe nanorods (NRs) with large molar extinction coefficients ((1.31 ± 0.01) × 10⁸ cm^–1·M^–1 at 808 nm, (7.00 ± 0.38) × 10⁷ cm^–1·M^–1 at 1064 nm) and high PCEs (70% at 808 nm, 48% at 1064 nm) were synthesized by living Staphylococcus aureus (S. aureus) cells as biosynthesis factories. Due to the strong light-absorbing and high photothermal conversion ability, the in vitro PA signals of CuTe NRs were about 6 times that of indocyanine green (ICG) in both NIR-I and NIR-II. In addition, CuTe NRs could effectively inhibit tumor growth through PTT. This work provides a new strategy for developing NIR-II probes with large molar extinction coefficients and high PCEs for NIR-II PAI and PTT.

中文翻译：

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用于 NIR-II 光声成像的大摩尔消光系数 CuTe 纳米棒的生物合成

第二近红外区（NIR-II）的光声成像（PAI）由于具有更深的组织穿透力和更低的背景干扰，引起了广泛关注。然而，开发具有大摩尔消光系数和高光热转换效率（PCE）的NIR-II纳米探针用于PAI和光热疗法（PTT）仍然是一个巨大的挑战。在这项工作中，NIR-II CuTe纳米棒（NR）具有大摩尔消光系数（（1.31 ± 0.01）× 10 ⁸ cm ^–1 ·M ^–1 at 808 nm，（7.00 ± 0.38）× 10 ⁷ cm ^–1 · M ^{–1 (1064 nm) 和高 PCE (70% (808 nm)、48% (1064 nm)) 由活}金黄色葡萄球菌( S. aureus ) 细胞作为生物合成工厂合成。由于CuTe NRs具有强光吸收和高光热转换能力，其体外PA信号在NIR-I和NIR-II中约为吲哚菁绿（ICG）的6倍。此外，CuTe NRs可以通过PTT有效抑制肿瘤生长。这项工作为开发具有大摩尔消光系数和高 PCE 的 NIR-II PAI 和 PTT 探针提供了新策略。