Lam Van K, Phan Thuc, Ly Khanh, Luo Xiaolong, Nehmetallah George, Raub Christopher B
Department of Biomedical Engineering, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA.
Department of Electrical Engineering and Computer Science, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA.
Biomed Opt Express. 2022 Jan 14;13(2):805-823. doi: 10.1364/BOE.449125. eCollection 2022 Feb 1.
Optical phase and birefringence signals occur in cells and thin, semi-transparent biomaterials. A dual-modality quantitative phase and polarization microscope was designed to study the interaction of cells with extracellular matrix networks and to relate optical pathlength and birefringence signals within structurally anisotropic biomaterial constructs. The design was based on an existing, custom-built digital holographic microscope, to which was added a polarization microscope utilizing liquid crystal variable retarders. Phase and birefringence channels were calibrated, and data was acquired sequentially from cell-seeded collagen hydrogels and electrofabricated chitosan membranes. Computed phase height and retardance from standard targets were accurate within 99.7% and 99.8%, respectively. Phase height and retardance channel background standard deviations were 35 nm and 0.6 nm, respectively. Human fibroblasts, visible in the phase channel, aligned with collagen network microstructure, with retardance and azimuth visible in the polarization channel. Electrofabricated chitosan membranes formed in 40 µm tall microfluidic channels possessed optical retardance ranging from 7 to 11 nm, and phase height from 37 to 39 µm. These results demonstrate co-registered dual-channel acquisition of phase and birefringence parameter maps from microstructurally-complex biospecimens using a novel imaging system combining digital holographic microscopy with voltage-controlled polarization microscopy.
光学相位和双折射信号出现在细胞以及薄的半透明生物材料中。设计了一种双模态定量相位和偏振显微镜，用于研究细胞与细胞外基质网络的相互作用，并关联结构各向异性生物材料构建体中的光程长度和双折射信号。该设计基于现有的定制数字全息显微镜，并在此基础上添加了利用液晶可变延迟器的偏振显微镜。对相位和双折射通道进行了校准，并从接种细胞的胶原水凝胶和电纺壳聚糖膜中依次采集数据。标准目标的计算相位高度和延迟的准确率分别在99.7%和99.8%以内。相位高度和延迟通道的背景标准偏差分别为35 nm和0.6 nm。在相位通道中可见的人成纤维细胞与胶原网络微观结构对齐，在偏振通道中可见延迟和方位角。在40 µm高的微流体通道中形成的电纺壳聚糖膜的光学延迟范围为7至11 nm，相位高度为37至39 µm。这些结果表明，使用一种将数字全息显微镜与电压控制偏振显微镜相结合的新型成像系统，可以从微观结构复杂的生物样本中共同记录相位和双折射参数图的双通道采集。
