Qi Caixia, Shen Lin, Li Jin, Sun Xun, Song Lehui, Chen Jiadong, Wu Yixuan, Choo Jaebum, Chen Lingxin
Shandong Applied Research Center of Gold Nanotechnology (Au-SDARC), School of Chemistry & Chemical Engineering, Yantai University, 264005 Yantai, China.
CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, 264003 Yantai, China.
ACS Appl Mater Interfaces. 2024 Dec 11;16(49):67333-67343. doi: 10.1021/acsami.4c15017. Epub 2024 Nov 27.
Near-infrared (NIR) surface-enhanced resonance Raman (SERRS) nanoprobes have found wide applications in biomedicine; however, almost all of these nanoprobes are fluorescent because the resonant Raman dyes used cannot be fully quenched onto the underlying plasmonic nanoparticles. Therefore, suppressing the fluorescence backgrounds in resonant Raman spectroscopy imaging is extremely important. In this work, we use a black hole quencher, IQ1, as a Raman dye to develop absolutely nonfluorescent NIR resonant SERRS NPs. Ultrafast spectroscopy clarifies that the nonfluorescent mechanism of the dyes is attributed to the ultrafast internal conversion at the subpicosecond scale, which quenches the fluorescence of excited states. The resultant nanoprobes exhibit zero fluorescent background, femtomolar-level sensitivity (100 fM) as well as superb photostability (τ = 10006 s) without fluorescence photobleaching, outperforming that of fluorescent counterparts. More importantly, the SERRS NPs show a synergistic photothermal effect originating from the dye molecule-plasmon interactions, achieving a high photothermal conversion efficiency of 64.94%. Featuring these excellent properties, these SERRS NPs allow for longitudinally photostable cellular imaging and enhanced photothermal elimination of cancer cells. To the best of our knowledge, this is the first example of absolutely nonfluorescent NIR SERRS NPs, opening up promising applications for improved phototheranostics.
近红外（NIR）表面增强共振拉曼（SERRS）纳米探针在生物医学领域有广泛应用；然而，几乎所有这些纳米探针都有荧光，因为所使用的共振拉曼染料无法完全淬灭到下层的等离子体纳米颗粒上。因此，在共振拉曼光谱成像中抑制荧光背景极为重要。在这项工作中，我们使用一种黑洞猝灭剂IQ1作为拉曼染料来开发完全无荧光的近红外共振SERRS纳米颗粒。超快光谱表明，染料的无荧光机制归因于亚皮秒尺度的超快内转换，这淬灭了激发态的荧光。所得的纳米探针表现出零荧光背景、飞摩尔级灵敏度（100 fM）以及出色的光稳定性（τ = 10006 s）且无荧光光漂白现象，优于有荧光的同类产品。更重要的是，SERRS纳米颗粒显示出源自染料分子 - 等离子体相互作用的协同光热效应，实现了64.94%的高光热转换效率。具有这些优异特性，这些SERRS纳米颗粒可实现纵向光稳定的细胞成像并增强对癌细胞的光热消除。据我们所知，这是完全无荧光的近红外SERRS纳米颗粒的首个实例，为改进的光热诊疗开辟了广阔的应用前景。
