Advances in biological imaging applications of fluorescent gold nanoclusters (invited)
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摘要: 金纳米团簇(AuNCs)因兼具优异荧光特性、超小尺寸、精确化学组成及良好生物相容性等优势,使其成为近些年备受关注的新型荧光探针。为了推动荧光AuNCs在成像领域的应用,研究者们一直致力于发展高性能荧光AuNCs的设计与制备策略。基于对AuNCs结构与发光机制的理解,诸如提高荧光量子产率和细胞摄取率等策略陆续被提出以增强AuNCs的细胞成像效果,极大提升了其作为荧光成像探针的潜力,并将AuNCs的应用推广至荧光寿命成像、多光子成像等新兴荧光成像技术。近些年发展的具有近红外二区荧光的AuNCs进一步推动了其在活体成像的应用。文中概述了AuNCs的制备方法、提高AuNCs细胞荧光成像效果的各种策略,以及AuNCs荧光成像应用的最新进展,并对该领域的挑战和未来发展进行了展望。Abstract: In recent years, due to the unique advantages such as excellent fluorescence properties, ultra-small size, precise chemical structure and good biocompatibility, gold nanoclusters (AuNCs) have become a kind of emerging fluorescent nanoprobe of great concern. In order to promote the application of AuNCs in fluorescence imaging, researchers have been devoted to designing preparation strategies for various high-performance fluorescent AuNCs. Based on the continuous understanding of the structure and luminescence mechanism of AuNCs, strategies such as enhancing the fluorescence quantum yield and cellular uptake of AuNCs have been proposed and applied to enhance the cellular imaging ability of AuNCs. These strategies greatly improve their potential as fluorescent imaging probes. Furthermore, fluorescent AuNCs are also utilized in advanced fluorescence imaging technologies such as fluorescence lifetime imaging and multi-photon fluorescence imaging. In addition, AuNCs with near-infrared II fluorescence have greatly promoted their application for in vivo imaging recently. This article summarizes the preparation methods of fluorescent AuNCs probes, reviews strategies to improve the fluorescence cellular imaging ability of AuNCs, and introduces the latest progress in the application of AuNCs in fluorescence imaging and also the challenges and future developments in the field.
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Key words:
- gold nanoclusters /
- fluorescence imaging /
- cell-targeting /
- fluorescent probes
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图 3 (a)荧光成像技术研究AuNCs进入细胞的过程[33];(b)在AuNCs表面修饰叶酸的示意图[38] ;(c)通过流式细胞术研究未修饰AuNCs (SG)与叶酸修饰AuNCs (FA)在具有不同叶酸受体表达水平的细胞的摄取量差异[38]
Figure 3. (a) Investigating the endocytosis of AuNCs by fluorescence imaging[33]; (b) Scheme of modification of folic acid on the surface of AuNCs[38]; (c) Differences in cellular uptake of unmodified AuNCs (SG) and folic acid-modified AuNCs (FA) in cells with different receptor expression levels by flow cytometry[38]
图 5 (a) AuNCs作为成像探针应用于荧光寿命成像技术[44];(b)利用AuNCs的多光子吸收性质实现细胞多光子成像[47];(c)高稳定性、高量子产率的AuNCs用于STED成像[48];(d) BSA-AuNCs用于超分辨径向涨落成像[49]
Figure 5. Fluorescent AuNCs for (a) fluorescence lifetime imaging[44], (b) multi-photon fluorescence imaging[47], (c) STED imaging[48] and (d) super-resolution radial fluctuations imaging[49]
图 7 (a) NIR-II荧光的AuNCs与Ln纳米颗粒结合实现活体内硫化氢比率荧光传感[57];(b) Gd掺杂的NIR-II荧光AuNCs实现MRI和NIR-II双模态成像[58]
Figure 7. (a) In vivo ratiometric fluorescence sensing of hydrogen sulfide by using NIR-II fluorescent AuNCs combined with Ln nanoparticles[57]; (b) NIR-II fluorescent AuNCs doped with Gd for MRI and NIR-II dual mode imaging[58]
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