Xu Xiao
School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin, People's Republic of China.
Lasers Med Sci. 2019 Apr;34(3):615-628. doi: 10.1007/s10103-018-2639-x. Epub 2018 Oct 22.
For nanoshell-assisted optical detection of cancers, gold shell, silica core (gold-silica) nanoshells are engineered to be the exogenous contrast agent. This work has performed systematic numerical parametric study to investigate the nonlinear dependences of the hemisphere diffuse reflectance on gold-silica nanoshells, laser irradiance, and hosting biology tissue. Planar phantom based tissue models have been constructed as platforms for study. The radiant transport equation (RTE) has been applied to mathematically describe the interactions among laser lights, hosting tissues, and hosted nanoshells. The diffuse reflectance signal under various combinations of parametric conditions has been computed and analyzed. Parametric parameters whose effects on the diffuse reflectance signal have been investigated are: (1) optical properties of a nanoshell generic, (2) nanoshell volume fraction, which is an indicator of nanoshell accumulation in the target tissue site, (3) the width of irradiating laser beam, and (4) thickness of the tissue slab. Seven nanoshell generics have been tested as the exogenous contrast agent including the R[50, 10] (radius of silica core is 50 nm and thickness of gold shell is 10 nm), R[55, 25], R[40, 15], R[40, 40], R[104, 23], R[75, 40] and R[154, 24] nanoshells. It has been found the R[55, 25] nanoshell works best as the exogenous contrast agent, the R[75, 40] and R[104, 23] nanoshells show good potentials as well while the R[50, 10] and R[40, 15] nanoshells should be avoided for diagnostic usage. The practice of neglecting the absorption characteristic of the exogenous contrast agent, which is quite common among the bio-nano community, has been proven to end up with an over-prediction of the effectiveness of the exogenous contrast agent. Such practice therefore is not well justified and should be avoided in future research. Interactions among laser lights, the tissue and nanoshells are highly nonlinear, demonstrated by that nanoshell generics with totally different optical properties might have similar effects on the diffuse reflectance signal and vice versa. Prior to any bench experiment, preliminary numerical investigation as this work has showcased is highly recommended.
对于纳米壳辅助的癌症光学检测，金壳、二氧化硅核（金 - 二氧化硅）纳米壳被设计为外源性造影剂。这项工作进行了系统的数值参数研究，以研究半球漫反射率对金 - 二氧化硅纳米壳、激光辐照度和宿主生物组织的非线性依赖性。基于平面体模的组织模型已被构建作为研究平台。辐射传输方程（RTE）已被用于从数学上描述激光、宿主组织和所含纳米壳之间的相互作用。已计算并分析了各种参数条件组合下的漫反射信号。已研究其对漫反射信号有影响的参数包括：（1）纳米壳通用光学性质，（2）纳米壳体积分数，它是纳米壳在目标组织部位积累的一个指标，（3）照射激光束的宽度，以及（4）组织平板的厚度。七种纳米壳通用类型已作为外源性造影剂进行测试，包括R[50, 10]（二氧化硅核半径为50纳米且金壳厚度为10纳米）、R[55, 25]、R[40, 15]、R[40, 40]、R[104, 23]、R[75, 40]和R[154, 24]纳米壳。已发现R[55, 25]纳米壳作为外源性造影剂效果最佳，R[75, 40]和R[104, 23]纳米壳也显示出良好的潜力，而R[50, 10]和R[40, 15]纳米壳应避免用于诊断用途。在生物纳米领域中很常见的忽略外源性造影剂吸收特性的做法，已被证明最终会导致对外源性造影剂有效性的过度预测。因此，这种做法没有充分的依据，在未来的研究中应避免。激光、组织和纳米壳之间的相互作用是高度非线性的，这表现为具有完全不同光学性质的纳米壳通用类型可能对漫反射信号有相似的影响，反之亦然。在进行任何实验台实验之前，强烈建议像本工作所展示的那样进行初步的数值研究。
