Figure 1.

Fabrication of microparticle-based gradient alginate hydrogels. (A) Photograph of gradient making system. (B) Flow rates of two syringes to pump a linear gradient for a 5-cm length × 2-mm diameter alginate hydrogel. After linear gradient pumping for 3 min, an additional 50 µL of alginate solution, which is the volume from the Y point to the beginning of quartz tube, was further pumped into a spiral mixer for 1 min. (C) Photomicrographs of microparticles in cross-sections of gradient alginate hydrogel segments. Segments 1–10 represent sequential segments of the gel. (D) Quantification of microparticles in each segment of gradient alginate hydrogels.