IEEE Trans Biomed Eng. 2021 Feb;68(2):706-711. doi: 10.1109/TBME.2020.3012663. Epub 2021 Jan 20.
In this study, we introduce the design, fabrication, and assessment of an optically and acoustically transparent, long-term and biocompatible cranial window for high-resolution photoacoustic microscopy of rat cerebral cortex.
The cranial window is fabricated with a polydimethylsiloxane (PDMS) layer bonded with a glass ring (outer diameter: 8 mm, inner diameter: 5 mm) via air plasma cleaning. A detailed comparison of image quality was performed with the implantation of cranial windows using different thicknesses of the PDMS film, and the cover glass. In addition, long-term in vivo monitoring of rat cerebral cortex was conducted to evaluate the stability of the cranial window. Furthermore, we successfully applied this window for longitudinal photoacoustic imaging in freely moving rats.
Based on a detailed evaluation, the cranial window fabricated with PDMS has a better imaging quality compared with a conventional cover-glass-based cranial window. The optimal film thickness is 50 μm considering the elastic deforming capability of PDMS. The cranial window maintained good quality for 21 and 12 days in anesthetized and free moving rats, respectively.
The cranial window has a good imaging quality for both anesthetized and behaving rats, enabling long-term, high-resolution, and steady photoacoustic imaging of cerebral vasculatures.
Based on the studies of both anesthetized and behaving rats, the proposed cranial window has the potential to be used in the longitudinal in vivo study of chronic brain diseases in freely moving rodents.
本研究介绍了一种光声透明、长期生物相容的颅窗的设计、制作和评估，用于大鼠大脑皮层的高分辨率光声显微镜检查。
通过空气等离子体清洗，将聚二甲基硅氧烷（PDMS）层与玻璃环（外径：8mm，内径：5mm）粘合，制作颅窗。通过不同厚度的 PDMS 膜和盖玻片的植入，对图像质量进行了详细比较。此外，还进行了大鼠大脑皮层的长期活体监测，以评估颅窗的稳定性。此外，我们成功地将该窗口应用于自由活动大鼠的纵向光声成像。
基于详细评估，与传统的盖玻片基颅窗相比，由 PDMS 制成的颅窗具有更好的成像质量。考虑到 PDMS 的弹性变形能力，最佳膜厚为 50μm。在麻醉和自由活动大鼠中，颅窗分别能保持 21 天和 12 天的良好质量。
该颅窗对麻醉和行为大鼠均具有良好的成像质量，能够实现大脑血管的长期、高分辨率、稳定的光声成像。
基于麻醉和行为大鼠的研究，所提出的颅窗有可能用于自由活动啮齿动物慢性脑部疾病的纵向体内研究。
