Figure 2.

Rapid “press-on” hydrogel patterning in an open-channel microarray chip. (A) Schematic illustration of press-on hydrogel confinement on patterned islands on PDMS substrate. (B) Demonstration of gel loading and press-on gel confinement using Collagen I (3 mg/mL) mixed with red or green food dye (top). Cross-sectional image of the device, yellow arrows indicate the stepped height of ~190 μm (bottom). (C) Fluorescence images of FITC-laden Collagen I confined within different shapes of hydrogel island. White dotted line indicates the shape of the patterned hydrogel island. (D) Schematic illustration of workflow for on-chip spheroid-in-gel formation. Schematics were created with BioRender.com.