Figure 1.

(A) Schematic of hydrogel fabrication process. Hydrogel units were fabricated by photolithography. 20 µL of gel precursor solution was pipetted onto a glass slide and then exposed to UV light (500 mW; at a height of 50 mm above the gels) for 20 seconds. (B) We used four types of photomasks with square patterns of different sizes (200 × 200 × 150 µm³, 400 × 400 × 150 µm³, 500 × 500 × 150 µm³, and 1000 × 1000 × 150 µm³) (C) Schematic diagram of hydrogel assembly process. After fabrication, hydrogels were transferred into a petri dish containing Phosphate-Buffered Saline (PBS), and magnetic field was applied. (D) Hydrogels were assembled into different shapes. The assembly was subsequently stabilized by a secondary crosslinking step. Phase image of assembled hydrogels were shown. (E) Fabrication of a celtic-shaped fluidic patterning chamber using multiple layers of thin poly-methyl methacrylate (PMMA) and double sided adhesive (DSA) sheets. The designed system is a fluidic chamber composed of three circular peripheral wells all connected to the primary rectangular well, where the assembly takes place.