To further test the printability of various PEG formulations, we produced different complex structures by heat-assisted DLP (Figures and). The 3D printed objects with gyroid architecture or Dprime surface showed high resolution and fine surface finish. After incubation in PBS pH 7.4 at 37 °C for 24 h, all objects maintained their structures with even better surface smoothness due to hydration. Moreover, no shape deformation that commonly occurs in conventional hydrogel printing was observed (Figures ). As shown in Figure , an average layer thickness of the object printed from PEGDMA 10k -PEGDA 700 (90/10, w/w) was about 58 µm, which is very close to the set value (50 µm). The hydrogel layer thickness was of 85 µm, with a size expanding ratio of ~1.5. This is consistent with the results obtained in the swelling test of the cylinder specimens. If needed, the layer thickness could be set to lower values (e.g., 25 µm) to further improve the z-resolution. Furthermore, we printed models of the human meniscus and ear, which are representative cartilagebased structures. Both of them displayed high fidelity and a smooth surface (Figures and). We further fabricated small-sized complex architectures using a trabecular model (f 3.20 mm ´ h 2.03 mm) with microchannels obtained by the CT scan of a trabecular bone core from a horse femur as described previously. It was found that the microstructure of the bone scaffold was well printed, with minimal feature size down to 50-60 µm (Figure ). The average print size deviation was calculated to be f -