光热疗法由于其安全和高效的优点, 作为一种非破坏性方法在癌症治疗中有广泛的应用前景。光热疗法中, 所采用的纳米颗粒在近红外波段的光热转换效率取决于纳米颗粒的光谱吸收特性。采用时域有限差分法对球型、壳型、杆型、片型、笼型、星型和花型等七种不同金纳米颗粒的光谱吸收特性进行了仿真计算, 结果表明纳米颗粒的几何参数和结构对其光谱吸收效率和共振波长产生了显著的影响。通过对比七种金纳米颗粒的体积吸收系数, 发现金纳米片在近红外波段的光热转换效率优于其他六种金纳米颗粒。从电流密度矢量分布得出, 金纳米颗粒内部产生共振电流是导致金纳米颗粒在近红外波段具有明显的单色吸收特性的原因。

Due to its safety and high efficiency, photothermal therapy has been actively explored as minimally invasive approach to cancer therapy. The selection of nanoparticles to achieve photo thermal conversion efficiently is based on the absorption properties of the nanoparticles. Finite difference time domain method(FDTD) was used to calculate spectral absorption efficiencies for seven common types of gold nanoparticles: nanospheres, nanoshells, nanorods, nanosheets, nanocages, nanostars, and nanoflowers. The calculated results clearly demonstrate the dependence of absorption efficiencies and resonance wavelengths on the geometrical parameters of the nanoparticles. Via the volume absorption efficiencies, photothermal performance of the seven types of gold nanoparticles is compared quantitatively. The gold nanosheets are proved to offer the most superior photothermal performance in the near-infrared region (NIR) among the seven types of nanoparticles. From the vector distributions of the electric current densities, it is clearly shown that the resonant electric currents in the gold nanoparticles play the major role on the ultra large absorption cross-section in the NIR.