Institute of Chemistry, Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14776 Potsdam, Germany.
Nanoscale. 2017 Feb 2;9(5):1951-1955. doi: 10.1039/c6nr08695k.
The excitation of localized surface plasmons in noble metal nanoparticles (NPs) results in different nanoscale effects such as electric field enhancement, the generation of hot electrons and a temperature increase close to the NP surface. These effects are typically exploited in diverse fields such as surface-enhanced Raman scattering (SERS), NP catalysis and photothermal therapy (PTT). Halogenated nucleobases are applied as radiosensitizers in conventional radiation cancer therapy due to their high reactivity towards secondary electrons. Here, we use SERS to study the transformation of 8-bromoadenine (A) into adenine on the surface of Au and AgNPs upon irradiation with a low-power continuous wave laser at 532, 633 and 785 nm, respectively. The dissociation of A is ascribed to a hot-electron transfer reaction and the underlying kinetics are carefully explored. The reaction proceeds within seconds or even milliseconds. Similar dissociation reactions might also occur with other electrophilic molecules, which must be considered in the interpretation of respective SERS spectra. Furthermore, we suggest that hot-electron transfer induced dissociation of radiosensitizers such as A can be applied in the future in PTT to enhance the damage of tumor tissue upon irradiation.
局部表面等离激元在贵金属纳米粒子（NPs）中的激发会产生不同的纳米级效应，如电场增强、热电子的产生和接近 NP 表面的温度升高。这些效应通常在表面增强拉曼散射（SERS）、NP 催化和光热治疗（PTT）等不同领域得到利用。卤代核苷碱基由于其对次级电子的高反应性，被用作传统放射治疗中的增敏剂。在这里，我们使用 SERS 来研究在 532、633 和 785nm 连续波激光照射下，8-溴腺嘌呤（A）在 Au 和 AgNPs 表面转化为腺嘌呤的过程。A 的解离归因于热电子转移反应，并且仔细探索了其潜在的动力学。该反应在几秒钟甚至几毫秒内进行。其他亲电分子也可能发生类似的解离反应，在解释各自的 SERS 谱时必须考虑到这一点。此外，我们建议，像 A 这样的增敏剂的热电子转移诱导解离可以在未来的 PTT 中应用，以增强肿瘤组织在照射下的损伤。
