Tissue engineering is a branch of regenerative medicine that aims to manipulate cells and scaffolds to create bioartificial tissues and organs for patients. A major challenge lies in monitoring the blood supply to the new tissue following transplantation: the integration and neovascularization of scaffolds in vivo is critical to their functionality. Photoacoustic imaging (PAI) is a laser-generated ultrasound-based technique that is particularly well suited to visualising microvasculature due to the high optical absorption of haemoglobin. Here, we describe an early proof-of-concept study in which PAI in widefield tomography mode is used to image biological, decellularized human tracheal scaffolds. We found that PAI allowed the longitudinal tracking of scaffold integration into subcutaneous murine tissue with high spatial resolution at depth over an extended period of time. The results of the study were consistent with post-imaging histological analyses, demonstrating that PAI can be used to non-invasively monitor the extent of vascularization in biological tissue-engineered scaffolds. We propose that this technique may be a valuable tool for studies designed to test interventions aimed at improving the speed and extent of scaffold neovascularization in tissue engineering. With technological refinement, it could also permit in vivo monitoring of revascularization in patients, for example to determine timing of heterotopic graft transfer.

组织工程是再生医学的一个分支，旨在操纵细胞和支架为患者创造生物人工组织和器官。主要挑战在于监测移植后新组织的血液供应：体内支架的整合和新生血管形成对其功能至关重要。光声成像 (PAI) 是一种基于激光产生超声波的技术，由于血红蛋白的高光吸收性，特别适合微血管可视化。在这里，我们描述了一项早期概念验证研究，其中使用宽场断层扫描模式下的 PAI 对生物脱细胞人类气管支架进行成像。我们发现，PAI 允许在较长时间内以高空间分辨率在深度上纵向跟踪支架整合到小鼠皮下组织中。该研究结果与成像后组织学分析一致，表明 PAI 可用于非侵入性监测生物组织工程支架中血管化的程度。我们认为，这项技术可能是一个有价值的研究工具，旨在测试旨在提高组织工程中支架新生血管形成的速度和程度的干预措施。随着技术的改进，它还可以对患者的血运重建进行体内监测，例如确定异位移植物移植的时间。