Photostable and efficient upconverting nanocrystal-based chemical sensors.
Photostable and efficient upconverting nanocrystal-based chemical sensors.
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DOI：
10.1016/j.optmat.2018.07.031
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发表时间：
2018-10
影响因子：
3.9
通讯作者：
Cheryl A. Tajon;Hao Yang;Bining Tian;Yue Tian;P. Ercius;P. Schuck;E. Chan;B. Cohen
中科院分区：
文献类型：
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作者：
Cheryl A. Tajon;Hao Yang;Bining Tian;Yue Tian;P. Ercius;P. Schuck;E. Chan;B. Cohen
生命系统中的化学传感要求光学传感器明亮，稳定，对化学信号的快速动态敏感。镧系元素掺杂的上转换纳米颗粒（UCNP）有效地将近红外（NIR）光转换为更高能量的发射，并允许生物系统在没有可测量的背景或光漂白的情况下成像，并且具有减少的散射用于亚表面实验。尽管它们作为成像探针的优势，UCNP几乎没有先天的化学传感能力，并且需要与有机荧光团配对以充当生物传感器，尽管具有有效上转换能量转移（UET）的稳定UCNP-荧光团混合物的设计仍然是一个挑战。在这里，我们报告的Yb 3+和Er 3+掺杂的UCNP-荧光团共轭物与UET效率高达88%，和光稳定性100倍以上的UET激发下的自由荧光团的直接激发。尽管增加了Er 3+供体和有机受体之间的距离，薄的惰性壳层显着提高整体发射，而不影响UET效率。这可以解释为在核/壳界面处的Er 3+供体的量子产率的大幅增加和在表面处的大量荧光团受体。由UET激发的传感器显示出光稳定性的增加远远超过了其他方法报道的增加有机荧光团的寿命，那些共价连接到UCNP表面聚合物显示出更大的化学稳定性比那些直接协调的表面。通过将其他荧光化学传感器与UCNP缀合，这些杂交体可以扩展到一系列NIR响应生物传感器，用于定量对细胞信号传导至关重要的动态化学群体。
Chemical sensing in living systems demands optical sensors that are bright, stable, and sensitive to the rapid dynamics of chemical signaling. Lanthanide-doped upconverting nanoparticles (UCNPs) efficiently convert near infrared (NIR) light to higher energy emission and allow biological systems to be imaged with no measurable background or photobleaching, and with reduced scatter for subsurface experiments. Despite their advantages as imaging probes, UCNPs have little innate chemical sensing ability and require pairing with organic fluorophores to act as biosensors, although the design of stable UCNP-fluorophore hybrids with efficient upconverted energy transfer (UET) has remained a challenge. Here, we report Yb3+- and Er3+-doped UCNP-fluorophore conjugates with UET efficiencies up to 88%, and photostabilities 100-fold greater by UET excitation than those of the free fluorophores under direct excitation. Despite adding distance between Er3+donors and organic acceptors, thin inert shells significantly enhance overall emission without compromising UET efficiency. This can be explained by the large increase in quantum yield of Er3+donors at the core/shell interface and the large number of fluorophore acceptors at the surface. Sensors excited by UET show increases in photostability well beyond those reported for other methods for increasing the longevity of organic fluorophores, and those covalently attached to UCNP surface polymers show greater chemical stability than those directly coordinated to the nanocrystal surface. By conjugating other fluorescent chemosensors to UCNPs, these hybrids may be extended to a series of NIR-responsive biosensors for quantifying the dynamic chemical populations critical for cell signaling.