Departamento de Física y Química Teórica and Departamento de Matemáticas, Facultad de Química, Universidad Nacional Autónoma de México, Mexico, Mexico.
Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France.
J Chem Phys. 2022 Feb 28;156(8):084701. doi: 10.1063/5.0078457.
Coating gold nanostructures with a silica shell has been long considered for biomedical applications, including photoacoustic imaging. Recent experimental and modeling investigations reported contradicting results concerning the effect of coating on the photoacoustic response of gold nanostructures. Enhanced photoacoustic response is generally attributed to facilitated heat transfer at the gold/silica/water system. Here, we examine the photoacoustic response of gold core-silica shell nanoparticles immersed in water using a combination of the two temperature model and hydrodynamic phase field simulations. Here, of particular interest is the role of the interfacial coupling between the gold electrons and silica shell phonons. We demonstrate that as compared to uncoated nanoparticles, photoacoustic response is enhanced for very thin silica shells (5 nm) and short laser pulses, but for thicker coatings, the photoacoustic performance are generally deteriorated. We extend the study to the regime of nanocavitation and show that the generation of nanobubbles may also play a role in the enhanced acoustic response of core-shell nanoparticles. Our modeling effort may serve as guides for the optimization of the photoacoustic response of heterogeneous metal-dielectric nanoparticles.
将金纳米结构涂覆二氧化硅壳层一直被用于生物医学应用，包括光声成像。最近的实验和模拟研究报告了关于涂层对金纳米结构光声响应的影响的相互矛盾的结果。光声响应增强通常归因于金/二氧化硅/水体系中传热的促进。在这里，我们使用双温模型和流体力学相场模拟的组合来研究浸入水中的金核-二氧化硅壳纳米粒子的光声响应。在这里，特别感兴趣的是金电子和二氧化硅壳声子之间的界面耦合的作用。我们证明，与未涂层的纳米粒子相比，光声响应在非常薄的二氧化硅壳（5nm）和短激光脉冲下增强，但对于较厚的涂层，光声性能通常会恶化。我们将研究扩展到纳米空化的范围，并表明纳米气泡的产生也可能在核壳纳米粒子的增强声响应中起作用。我们的建模工作可以作为优化异质金属-电介质纳米粒子的光声响应的指南。
