Photoswitchable NIR-Emitting Gold Nanoparticles
Photoswitchable NIR-Emitting Gold Nanoparticles
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DOI：
10.1002/anie.201604290
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发表时间：
2016-09-05
影响因子：
16.6
通讯作者：
Montalti, Marco
中科院分区：
文献类型：
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作者：
Bonacchi, Sara;Cantelli, Andrea;Montalti, Marco
证明了金纳米颗粒（GNP）在结合到表面的偶氮苯配体发生光异构化时的近红外发射的光转换。光物理结果证实了从配体到 GNP 的激发能量转移过程的发生，产生敏化近红外发射。由于这一过程，在激发配体时，反式金核的激发效率比顺式高得多，并且 tc 光异构化导致 GNP NIR 发射相应减少。因此，可以通过双激发时近红外发射的比率检测来监测光异构化。通过使用专用装置同时检测吸光度和发光变化来实时跟踪光异构化过程。令人惊讶的是，结合到 GNP 表面的配体的光异构化速率与溶液中生色团的测量结果相同。这一结果表明，激发能量转移到金有助于光异构化，而不是与之竞争。这些结果为开发用于治疗诊断的新型近红外发射刺激响应纳米材料铺平了道路。
Photo-switching of the NIR emission of gold nanoparticles (GNP) upon photo-isomerization of azobenzene ligands, bound to the surface, is demonstrated. Photophysical results confirm the occurrence of an excitation energy transfer process from the ligands to the GNP that produces sensitized NIR emission. Because of this process, the excitation efficiency of the gold core, upon excitation of the ligands, is much higher for the trans form than for the cis one, and tc photo-isomerization causes a relevant decrease of the GNP NIR emission. As a consequence, photo-isomerization can be monitored by ratiometric detection of the NIR emission upon dual excitation. The photo-isomerization process was followed in real-time through the simultaneous detection of absorbance and luminescence changes using a dedicated setup. Surprisingly, the photo-isomerization rate of the ligands, bound to the GNP surface, was the same as measured for the chromophores in solution. This outcome demonstrated that excitation energy transfer to gold assists photo-isomerization, rather than competing with it. These results pave the road to the development of new, NIR-emitting, stimuli-responsive nanomaterials for theranostics.