Halaney David L, Katta Nitesh, Fallah Hamidreza, Aguilar Guillermo, Milner Thomas E
Laboratory of Guillermo Aguilar, Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States.
Laboratory of Thomas Milner, Department of Biomedical Engineering, University of Texas, Austin, TX, United States.
Front Bioeng Biotechnol. 2021 Mar 19;9:619686. doi: 10.3389/fbioe.2021.619686. eCollection 2021.
Transparent "Window to the Brain" (WttB) cranial implants made from a biocompatible ceramic, nanocrystalline Yttria-Stabilized Zirconia (nc-YSZ), were recently reported. These reports demonstrated chronic brain imaging across the implants in mice using optical coherence tomography (OCT) and laser speckle imaging. However, optical properties of these transparent cranial implants are neither completely characterized nor completely understood. In this study, we measure optical properties of the implant using a swept source OCT system with a spectral range of 136 nm centered at 1,300 nm to characterize the group refractive index of the nc-YSZ window, over a narrow range of temperatures at which the implant may be used during imaging or therapy (20-43°C). Group refractive index was found to be 2.1-2.2 for OCT imaging over this temperature range. Chromatic dispersion for this spectral range was observed to vary over the sample, sometimes flipping signs between normal and anomalous dispersion. These properties of nc-YSZ should be considered when designing optical systems and procedures that propagate light through the window, and when interpreting OCT brain images acquired across the window.
最近报道了一种由生物相容性陶瓷——纳米晶氧化钇稳定氧化锆（nc-YSZ）制成的透明“脑窗”（WttB）颅骨植入物。这些报道展示了在小鼠体内通过植入物利用光学相干断层扫描（OCT）和激光散斑成像进行的慢性脑成像。然而，这些透明颅骨植入物的光学特性既未得到完全表征，也未被完全理解。在本研究中，我们使用一个扫频源OCT系统测量植入物的光学特性，该系统的光谱范围为136纳米，中心波长为1300纳米，以表征nc-YSZ窗口在成像或治疗期间植入物可能使用的较窄温度范围（20 - 43°C）内的群折射率。发现在该温度范围内进行OCT成像时，群折射率为2.1 - 2.2。观察到该光谱范围内的色散在样品上有所变化，有时在正常色散和反常色散之间改变符号。在设计使光透过窗口传播的光学系统和程序时，以及在解释通过窗口获取的OCT脑图像时，应考虑nc-YSZ的这些特性。
