金纳米颗粒的摄入对细胞光学性质影响的数值仿真

Numerical simulation of the effects of gold nanoparticles on optical properties of biological cells

采用时域有限差分法(FDTD)方法计算了细胞摄入金纳米颗粒后的消光光谱,并对金纳米颗粒在细胞中3种不同的分布做了比较:金纳米颗粒均匀分布细胞膜上;金纳米颗粒在细胞质内均匀分布,不存在于细胞核中;金纳米颗粒在整个细胞中均匀分布.分析结果表明,由于金纳米颗粒的等离子共振效应,细胞在可见光区域的散射截面产生增强,并且其消光光谱的峰形和消光峰的位置也发生相应的变化,这种变化依赖于金纳米颗粒在细胞内的分布情况.当金纳米颗粒在细胞膜上均匀分布的时候,细胞的消光光谱的峰值最大,而另外2种情况则形成较宽的消光峰.计算结果有助进一步理解纳米颗粒在细胞内的扩散或生长的过程.

The finite-difference time-domain method （FDTD） is employed to study the optical properties of gold nanoparticles （NPs） introduced into biological cells with different distributions. Three distribution types of gold NPs in the cell are taken into consideration ： NPs are homogeneously localized in the cell membrane; NPs are homogeneously localized in the cytoplasm, not in nucleus; NPs are homogeneously localized in the whole cell. The results indicate that gold NPs enhance the light scattering cross section of the cells in visible-light region and change the extinction spectra specifically,which depends on the distribution of the Nps due to surface plasmon resonance. When NPs are homogeneously localized in the cell membrane, the extinction spectra exhibit the maximal plasmon peak while the other two cases have lower, broader surface plasmon features. It gives us a profound understanding of the dispersion and growth behavior of NPs in cells.