IEEE Trans Nanobioscience. 2017 Oct;16(7):542-554. doi: 10.1109/TNB.2017.2741490. Epub 2017 Aug 18.
A novel nanoparticle mediated methodology for laser photocoagulation of the inner retina to achieve tissue selective treatment is presented.
Transport of 527, 577, and 810 nm laser, heat deposition, and eventual thermal damage in vitreous, retina, RPE, choroid, and sclera were modeled using Bouguer-Beer-Lambert law of absorption and solved numerically using the finite volume method. Nanoparticles were designed using Mie theory of scattering. Performance of the new photocoagulation strategy using gold nanospheres and gold-silica nanoshells was compared with that of conventional methods without nanoparticles. For experimental validation, vitreous cavity of ex vivo porcine eyes was infused with gold nanospheres. After ~6 h of nanoparticle diffusion, the porcine retina was irradiated with a green laser and imaged simultaneously using a spectral domain optical coherence tomography (Spectralis SD-OCT, Heidelberg Engineering).
Our computational model predicted a significant spatial shift in the peak temperature from RPE to the inner retinal region when infused with nanoparticles. Arrhenius thermal damage in the mid-retinal location was achieved in ~14 ms for 527 nm laser thereby reducing the irradiation duration by ~30 ms compared with the treatment without nanoparticles. In ex vivo porcine eyes infused with gold nanospheres, SD-OCT retinal images revealed a lower thermal damage and expansion at RPE due to laser photocoagulation.
Nanoparticle infused laser photocoagulation strategy provided a selective inner retinal thermal damage with significant decrease in laser power and laser exposure time.
The proposed treatment strategy shows possibilities for an efficient and highly selective inner retinal laser treatment.
目的：提出了一种新的基于纳米颗粒的内视网膜激光光凝方法，以实现组织选择性治疗。
方法：使用光吸收的布格-比尔-朗伯定律和有限体积法对 527、577 和 810nm 激光的传输、热沉积以及玻璃体、视网膜、RPE、脉络膜和巩膜的最终热损伤进行了建模。使用 Mie 散射理论设计了纳米颗粒。使用金纳米球和金-硅纳米壳对新的光凝策略的性能进行了比较，与无纳米颗粒的传统方法进行了比较。为了进行实验验证，将金纳米球注入离体猪眼的玻璃体腔。在纳米颗粒扩散约 6 小时后，用绿光激光照射猪视网膜，并同时使用光谱域光学相干断层扫描（海德堡工程公司的 Spectralis SD-OCT）进行成像。
结果：我们的计算模型预测，当注入纳米颗粒时，峰值温度从 RPE 向内层视网膜区域发生显著的空间位移。在 527nm 激光照射下，中层视网膜位置的 Arrhenius 热损伤在 14ms 内即可达到，与无纳米颗粒治疗相比，激光照射时间减少了约 30ms。在注入金纳米球的离体猪眼，SD-OCT 视网膜图像显示由于激光光凝，RPE 处的热损伤和扩张程度较低。
结论：纳米颗粒注入激光光凝策略可实现选择性的内层视网膜热损伤，同时显著降低激光功率和激光照射时间。
意义：所提出的治疗策略为高效、高度选择性的内层视网膜激光治疗提供了可能性。
