Abstract Biosensing of circulating tumor cells (CTCs) is of vital significance in cancer theranostics. Thus, the development of highly efficient luminescent nano-bioprobes is imperative to meet the growing demand of CTCs-related clinical diagnosis and biomedical research. Herein, we exquisitely manipulate the stoichiometry of Se/In to synthesize CuInSe2 (CISe) quantum dots (QDs) with near-infrared (NIR) emission peak tunable from 920 to 1224 nm. Meanwhile, the excitation band of these CISe QDs spans from ultraviolet to NIR regions, which is highly desired for various bioapplications. Through surface coating of thin ZnS shell, an absolute NIR-II photoluminescence quantum yield of 21.8% can be achieve, which is the highest among Pb/Cd-free QDs reported so far. By virtue of their intense NIR-II emission, we demonstrate the application of CISe nanoprobes for autofluorescence-free bioassay of CTCs (e.g., human breast cancer MCF-7 cells) spiked in whole blood samples, with the limit of detection down to 12 cell/well of a 96-well plate. Furthermore, the CISe@ZnS nanoprobes are exploited for tumor-targeted bioimaging in live mice with a signal-to-noise ratio of 5.8. These findings reveal the great potentials of the novel NIR-II luminescent CuInSe2 nanoprobes in the field of cancer diagnosis and imaging-guided surgery.

中文翻译：

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基于CuInSe2量子点的宽带可激发NIR-II发光纳米生物探针用于检测循环肿瘤细胞

摘要 循环肿瘤细胞 (CTC) 的生物传感在癌症治疗诊断学中具有重要意义。因此，开发高效的发光纳米生物探针对于满足 CTC 相关临床诊断和生物医学研究日益增长的需求势在必行。在此，我们巧妙地操纵 Se/In 的化学计量来合成 CuInSe2 (CISe) 量子点 (QD)，其近红外 (NIR) 发射峰可从 920 到 1224 nm 可调。同时，这些 CISe QD 的激发带跨越了从紫外到近红外区域，这是各种生物应用非常需要的。通过表面涂覆薄的 ZnS 壳，可以实现 21.8% 的绝对 NIR-II 光致发光量子产率，这是迄今为止报道的无 Pb/Cd QD 中最高的。由于它们强烈的 NIR-II 发射，我们展示了 CISe 纳米探针在全血样品中掺入的 CTC（例如，人乳腺癌 MCF-7 细胞）的无自体荧光生物测定中的应用，检测限低至 96 孔板的 12 个细胞/孔。此外，CISe@ZnS 纳米探针用于活小鼠的肿瘤靶向生物成像，信噪比为 5.8。这些发现揭示了新型 NIR-II 发光 CuInSe2 纳米探针在癌症诊断和成像引导手术领域的巨大潜力。