Morphologic reconstruction of 2D cellular micro-scaffold based on digital holographic feedback

The artificial 2D cellular micro-scaffold is increasingly needed in tissue engineering and biomedical engineering. Yet, the study of the influence between the scaffold physical properties and the cell behaviors during cell cultures still remains lacking. In this paper, the micro-scaffold based on the PEGDA hydrogel was fabricated by combining digital holographic microscope technique and DMD-based manipulation system. The morphology and thickness coefficients of the micro-scaffold shaped under the UV exposure was sampled in real-time by the holographic microscopy as the feedback and utilized to control the DMD-based local solidification of the micro-scaffold, which can modify and reconstruct the morphology of the scaffold to improve the fidelity of the shape. With this technique, the system can fabricate micro-scaffold with any customized shape and thickness, which can be seeded or encapsulated with cells to study the influence of substrate mechanism to the cell behaviors under micro-nano scale. The RGDS-linked (Arg-Gly-Asp-Ser) PEGDA as a typical hydrogel was utilized to fabricate the micro-scaffold to verify the effectiveness of the system. Through encapsulating NIH/3T3 cells inside scaffold with different morphologies, we cultured the cells for 7 days and evaluate the cell behaviors. As a result, the NIH/3T3 cell can maintain different proliferation speed with very high cell viability. The proposed micro-scaffold fabrication method provide novel techniques for more accurate biofabrication of microtissues for the future regenerative medicine.