Nagda Riddhi, Shah Pratik, Lee Chang Seop, Park Sooyeon, Yang Seong Wook
Department of Systems Biology, College of Life Science and Biotechnology, Institute of Life Science and Biotechnology, Yonsei University, Seoul 03722, Korea.
UNIK Center for Synthetic Biology, University of Copenhagen, Thorvaldsensvej 40, 2000 Frederiksberg, Copenhagen, Denmark.
Nanomaterials (Basel). 2019 Apr 28;9(5):667. doi: 10.3390/nano9050667.
DNA-encapsulated Silver Nanoclusters (DNA/AgNCs) based sensors have gained increasing attention in past years due to their diverse applications in bioimaging, biosensing, and enzymatic assays. Given the potential of DNA/AgNCs for practical applications, the systematic studies of the fluorescent stability over an extended period is necessary. However, the correlation between nucleic acid properties and the long-term stability of DNA/AgNCs is less known. With locking-to-unlocking sensors, in which the secondary structure of DNA template is standardized, we investigated the correlation between the DNA structure and the fluorescence stability of AgNCs. Post-synthesis of DNA/AgNCs, the fluorescence, and structures of templates were monitored over three weeks. By combining the fluorescence spectroscopy with the in-gel fluorescent assay, we found that AgNCs encapsulated by dimer-structured DNA/AgNCs templates were more stable than those of hairpin-structured DNA/AgNCs templates. While the orange fluorescence from the dimer templates increased over three weeks, the red fluorescence from the hairpin templates was diminished by >80% within two days at room temperature. Further tests revealed that hairpin-encapsulated red-emissive AgNCs is more sensitive to oxidation by atmospheric oxygen compared to dimer encapsulated orange AgNCs. Our observations may provide an important clue in encapsulating photophysically more stable AgNCs by tuning the DNA secondary structures. The proposed strategy here can be essential for pragmatic applications of DNA/AgNCs templates.
基于DNA包裹的银纳米簇（DNA/AgNCs）的传感器在过去几年中受到了越来越多的关注，因为它们在生物成像、生物传感和酶分析等方面有多种应用。鉴于DNA/AgNCs在实际应用中的潜力，有必要对其在较长时间内的荧光稳定性进行系统研究。然而，核酸性质与DNA/AgNCs长期稳定性之间的相关性却鲜为人知。通过使用锁定到解锁传感器（其中DNA模板的二级结构是标准化的），我们研究了DNA结构与AgNCs荧光稳定性之间的相关性。在合成DNA/AgNCs后，对模板的荧光和结构进行了为期三周的监测。通过将荧光光谱与凝胶内荧光测定相结合，我们发现由二聚体结构的DNA/AgNCs模板包裹的AgNCs比发夹结构的DNA/AgNCs模板包裹的AgNCs更稳定。虽然二聚体模板发出的橙色荧光在三周内增加，但发夹模板发出的红色荧光在室温下两天内减少了80%以上。进一步的测试表明，与二聚体包裹的橙色AgNCs相比，发夹包裹的红色发射AgNCs对大气中的氧气氧化更敏感。我们的观察结果可能为通过调整DNA二级结构来包裹光物理性质更稳定的AgNCs提供重要线索。这里提出的策略对于DNA/AgNCs模板的实际应用可能至关重要。
