Department of Materials Science and Engineering , Southern University of Science and Technology , 1088 Xueyuan Blvd. , Nanshan District, Shenzhen , Guangdong 518055 , P. R. China.
ACS Appl Mater Interfaces. 2018 Aug 8;10(31):26075-26083. doi: 10.1021/acsami.8b09152. Epub 2018 Jul 24.
Oligonucleotide-stabilized silver nanoclusters (AgNCs) show promising applications in bioimaging and bio-/chemo-sensing. However, their unsatisfactory photostability limits their practical applications. In this work, fluorescent AgNCs were synthesized in situ in a DNA hydrogel, consisting of cross-linked enzymatically amplified polymeric DNAs with cytosine-rich sequences in the presence of Ag. The fluorescence property of the resultant AgNCs was optimized by a rational design of the DNA sequences to cover a broad spectrum with comparable green and red emissions. Under the protection of the DNA hydrogel, the AgNCs showed significantly improved photostability in an ambient oxygen environment, as well as low cytotoxicity even at a high concentration. Therefore, these properties show the rolling-circle-amplification-stabilized AgNCs to be a promising possible fluorescent probe for the detection of reactive oxygen/nitrogen species (ROS/RNS) in live cells because red-emitting species are susceptible to oxidation and consequently convert to green-emitting species. Finally, the as-prepared AgNCs were demonstrated to be a sensitive and specific probe for cellular imaging and the monitoring of ROS/RNS levels, which broadens the applications of AgNCs and provides a new tool for related biological investigations.
寡核苷酸稳定的银纳米簇 (AgNCs) 在生物成像和生物/化学传感方面具有广阔的应用前景。然而，其较差的光稳定性限制了它们的实际应用。在这项工作中，AgNCs 在 DNA 水凝胶中就地合成，该水凝胶由具有富含胞嘧啶序列的交联酶扩增聚合物 DNA 组成，在 Ag 的存在下形成。通过对 DNA 序列的合理设计，优化了所得 AgNCs 的荧光性质，以覆盖具有可比绿色和红色发射的宽光谱。在 DNA 水凝胶的保护下，AgNCs 在环境氧气环境中表现出显著提高的光稳定性，并且即使在高浓度下也表现出低细胞毒性。因此，这些性质表明滚环扩增稳定的 AgNCs 是一种很有前途的荧光探针，可用于检测活细胞中的活性氧/氮物种 (ROS/RNS)，因为红色发射物种容易被氧化，因此转化为绿色发射物种。最后，所制备的 AgNCs 被证明是一种用于细胞成像和 ROS/RNS 水平监测的灵敏和特异性探针，这拓宽了 AgNCs 的应用，并为相关的生物学研究提供了新工具。
