Abstract Plasmonic nanoparticles (NPs) are exploited to concentrate light, provide local heating and enhance drug release when coupled to smart polymers. However, the role of NP assembling in these processes is poorly investigated, although their superior performance as nanoheaters has been theoretically predicted since a decade. Here we report on a compound hydrogel (agarose and carbomer 974P) loaded with gold NPs of different configurations. We investigate the dynamics of light-heat conversion in these hybrid plasmonic nanomaterials via a combination of ultrafast pump-probe spectroscopy and hot-electrons dynamical modeling. The photothermal study ascertains the possibility to control the degree of assembling via surface functionalization of the NPs, thus enabling a tuning of the photothermal response of the plasmon-enhanced gel under continuous wave excitation. We exploit these assemblies to enhance photothermal release of drug mimetics with large steric hindrance loaded in the hydrogel. Using compounds with an effective hydrodynamic diameter bigger than the mesh size of the gel matrix, we find that the nanoheaters assemblies enable a two orders of magnitude faster cumulative drug release toward the surrounding environment compared to isolated NPs, under the same experimental conditions. Our results pave the way for a new paradigm of nanoplasmonic control over drug release.

中文翻译：

---

载有金纳米颗粒组件的琼脂糖凝胶中药物释放效率的等离子体控制

摘要 等离子纳米粒子 (NPs) 与智能聚合物结合时被用来聚集光、提供局部加热和增强药物释放。然而，NP 组装在这些过程中的作用很少被研究，尽管自 10 年以来，它们作为纳米加热器的优越性能一直在理论上被预测。在这里，我们报告了负载不同配置的金纳米颗粒的复合水凝胶（琼脂糖和卡波姆 974P）。我们通过超快泵浦探针光谱和热电子动力学建模的组合研究了这些混合等离子体纳米材料中光热转换的动力学。光热研究确定了通过纳米颗粒的表面功能化来控制组装程度的可能性，从而能够在连续波激发下调整等离子体增强凝胶的光热响应。我们利用这些组件来增强水凝胶中加载的具有大空间位阻的药物模拟物的光热释放。使用有效流体动力学直径大于凝胶基质网孔尺寸的化合物，我们发现，在相同的实验条件下，与孤立的 NP 相比，纳米加热器组件使向周围环境的累积药物释放速度提高了两个数量级。我们的结果为纳米等离子体控制药物释放的新范式铺平了道路。使用有效流体动力学直径大于凝胶基质网孔尺寸的化合物，我们发现，在相同的实验条件下，与孤立的 NP 相比，纳米加热器组件使向周围环境的累积药物释放速度提高了两个数量级。我们的结果为纳米等离子体控制药物释放的新范式铺平了道路。使用有效流体动力学直径大于凝胶基质网孔尺寸的化合物，我们发现在相同的实验条件下，与孤立的 NPs 相比，纳米加热器组件使向周围环境的累积药物释放速度提高了两个数量级。我们的结果为纳米等离子体控制药物释放的新范式铺平了道路。