Abstract Rationale Lung undergoes continuous deformation during breathing, which would influence the functions of lung resident cells and the progression of diseases such as metastasis. However, current imaging techniques have limitations in precisely analyzing the relation between the lung motion and disease progression. Histology offers high-resolution snapshots of cellular distribution and genetic expression, but it lacks information regarding dynamic processes such as breathing motion and immune cell dynamics. In vivo thoracic imaging window allows the real-time observation of lung structure and immune motility, it is limited to small region of interest and suppresses the breathing motion during imaging. We recently developed crystal ribcage system (Nature Methods, 2023) that enables high spatiotemporal resolution imaging under the physiological motion; however, high-resolution real-time imaging across the entire surface of a functioning lung has remained challenging. To overcome these limitations, we developed a robotic arm-assisted crystal ribcage platform for mapping across the whole lung surface. Methods For the whole lung surface imaging, the harvested lung was mounted in the ex vivo crystal ribcage platform and connected to a robot arm (Meca 500). Fluorescent images were obtained using a Nikon V3 spinning disk microscope. This robot arm provides precise six-degree-of-freedom motion control, enabling highly repeatable surface scanning. To induce the metastatic tumor, B16 melanoma cell expressing green fluorescent protein (B16-GFP) were injected into mTmG mice through the tail vein and lungs were harvested at day 11 post-injection for the imaging. Results For the high-resolution mapping of the curved lung surface, we divided the surface into smaller imaging regions based on local curvature. The robot arm adjusted the position and orientation of the ex vivo crystal ribcage so that each region could be aligned with the field of view of the microscope objective (Figure 1A and 1B). With the curvature-adaptive motion of the ex vivo lung, it was possible to obtain the fluorescent images of metastatic tumor nodules and alveoli for the entire lobe (Figure 1C). The perfusion and ventilation of the lung can be synchronized with the microscope and the robot arm. Conclusionand Future Work Our robot arm-based ex vivo crystal ribcage platform enables the longitudinal and whole-lung mapping of the lung. This system will be utilized to capture the dynamic time-lapse mapping of immune cell motility, tissue structure, and distensibility of the lung during disease progression to uncover the mechanobiological driver of lung pathology. This abstract is funded by: National Institutes of Health (DP2HL168562), Beckman Young Investigator Award, NSF CAREER Award
Kang et al. (Fri,) studied this question.