In vitro remodeling and structural characterization of degradable polymer scaffold-based tissue-engineered vascular grafts using optical coherence tomography

Non-destructive imaging strategies to monitor long-term cultures is essential for vascular engineering. The goal of this study is to investigate whether optical coherence tomography (OCT) can be a suitable approach to monitor the long-term remodeling process of biodegradable polymeric scaffold-based tissue-engineered vascular grafts (TEVG) after pulsatile stimulation and to observe polymeric scaffold degradation during bioreactor cultivation. In the present study, a perfusion system driven by a ventricular assist device was provided for a three-dimensional culture system as a pulsatile force. We characterized the structural features of wall thickness and polyglycolic acid degradation based on optical signal attenuation using catheter-based OCT. Scanning electron microscopy confirmed morphological changes. Also, polymer degradation and the detection of different types of collagen was visualized after 4 weeks of culture by means of polarized microscopy. Findings on OCT imaging correlated with those on histological examination and revealed the effects of pulsatile stimulation on the development of engineered vessels. This finding demonstrated that real-time imaging with OCT may be a promising tool for monitoring the growth and remodeling characterization of TEVG and provide a basis to promote the ideal and long-term culture of vascular tissue engineering.