Automated Fabrication of the High-Fidelity Cellular Micro-Scaffold through Proportion-Corrective Control of the Photocuring Process

Fabricated cellular micro-scaffold that recapitulates natural extracellular matrix (ECM) has shown huge potential in the study of cell behaviors. However, the reproducing of the physiological morphology with high efficiency and accuracy in the micro-scaffold still remains as a major challenge. Here, we propose a novel automated fabrication method to engineer high-fidelity cellular micro-scaffold with a proportion-corrective control algorithm to modulate the photocuring process of biodegradable hydrogel in real-time. A digital holographic microscopy (DHM) system is integrated into the micro-fabrication system based on the digital micro-mirror device (DMD) to enable the real-time detection of the photocuring process. Before the photocuring, the theoretical curing thickness is determined by the calibrated model. To fabricate a micro-scaffold with high-fidelity morphology, the incident UV light is divided into different grid areas and achieve local discrete photocuring control. For every local area, the real-time added value of the cured thickness is compared with the theoretical value to determine the distortion which is corrected by the second-step exposure controlled by the proportion-corrective algorithm. Finally, the algorithm efficiently improved the fabrication accuracy from 200μm to 50μm. With the long-term culture, the cells viabilities exceeded 96%. The experimental results verified the effectiveness and feasibility of the proposed control algorithm.