The growing demand for tissue engineered vascular grafts (TEVG) motivates the development of optimized fabrication and monitoring procedures. Bioreactors which provide physiologically-relevant conditions are important for improving holistic TEVG properties and performance. Herein we describe a fiber-based intraluminal imaging system that allows for in situ assessment of vascular materials and re-cellularization processes inside a bioreactor by simultaneous and co-registered measurements of endogenous fluorescence lifetime and exogenous marker fluorescence intensity. The lumen of 6 vascular grafts (∼4 mm diameter) were scanned by reciprocally rotating a 41° angle polished multimode optical fiber inside a protective glass tube with outer diameter of 3 mm. Tubular bovine pericardium constructs were recellularized using enhanced Green Fluorescent Protein (eGFP) transfected cells in a custom bioreactor. The imaging system has resolved consistently the cellular autofluorescence from that of tissue matrix in situ based on the lifetime fluorescence properties of endogenous molecular species. The location of the re-cellularized area was validated by the eGFP emission. Current results demonstrate the potential of this system as a valuable tool in tissue engineering for in situ studies of cell-tissue interactions in cylindrical or other 3-dimensional structures.

中文翻译：

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生物反应器内部工程化血管移植物中组织自体荧光和eGFP标记细胞的同时腔内成像。

对组织工程血管移植物（TEVG）的需求不断增长，推动了优化制造和监测程序的发展。提供生理相关条件的生物反应器对于改善整体TEVG特性和性能很重要。本文中，我们描述了一种基于纤维的腔内成像系统，该系统可通过同时和共注册内源荧光寿命和外源标记荧光强度的测量值，对生物反应器内的血管材料和再细胞化过程进行原位评估。通过在外径为3 mm的保护性玻璃管内往复旋转41°角抛光多模光纤，扫描6个血管移植物的内腔（直径约4 mm）。在定制的生物反应器中，使用增强的绿色荧光蛋白（eGFP）转染的细胞将管状牛心包构建体重新细胞化。基于内源性分子物种的终生荧光特性，成像系统从原位组织基质中一直分辨出细胞自发荧光。通过eGFP发射验证了重新细胞化区域的位置。当前结果表明，该系统作为组织工程中有价值的工具的潜力，可用于圆柱或其他3维结构中细胞-组织相互作用的原位研究。通过eGFP发射验证了重新细胞化区域的位置。当前结果表明，该系统作为组织工程中有价值的工具的潜力，可用于圆柱或其他3维结构中细胞-组织相互作用的原位研究。通过eGFP发射验证了重新细胞化区域的位置。当前结果表明，该系统作为组织工程中有价值的工具的潜力，可用于圆柱或其他3维结构中细胞-组织相互作用的原位研究。