In situ process monitoring and automated multi-parameter evaluation using optical coherence tomography during extrusion-based bioprinting

In three-dimensional (3D) bioprinting, errors during the printing process leads to lower structural fidelity, and the desired structural and functional performances cannot be fully satisfied. Process monitoring with high-speed imaging techniques is helpful for identifying material deposition errors. 3D reconstruction of printed objects enables comprehensive evaluation of structural characteristics, with wide-field full-depth imaging being necessary for large objects. In this study, we demonstrate 3D extrusion-based bioprinter-associated optical coherence tomography (3D P-OCT) to achieve high-speed, wide-field and full-depth imaging, and provide in situ process monitoring and comprehensive evaluation for 3D bioprinting. In 3D P-OCT, a wide field was achieved with a lateral image mosaic using the simplified iterative closest point algorithm, and the extension of imaging depth was achieved with a longitudinal image mosaic using image fusion based on maximum intensity values. During the printing process, 3D P-OCT enables real-time multi-parameter quantification for intelligent feedback. In conclusion, with in situ process monitoring and evaluation, 3D P-OCT contributes to ensure better structural and functional performances of 3D functional tissue constructs.