Submitted by: Van Thuy Duong

Category: Microscopy

Creation: We attempted to achieve spatially dynamic stiffening and softening within the same dSIS-NB-only (our novel bimaterial) gel using micropatterning with the LumenX bioprinter. A simple Purdue University logo was designed using the TinkerCAD website. The logo consisted of two parts: a larger ‘P’ designated for stiffening and a smaller ‘P’ for softening, which overlaid the larger ‘P’. The pre-formed soft gel was stiffened for 60 seconds with 0.5 mM tartrazine, and the larger ‘P’ appeared on the gel in a darker color. The gel was then washed and incubated with 5 mM Rh-PEGSH (red fluorescent molecules) and 6 mM LAP (photo initiator) before exposure with the smaller ‘P’ for 60seconds with 0.5 mM tartrazine. The smaller ‘P’ overlaid the larger ‘P’ to form a Purdue University logo. The red area was initially soft, then stiffened, and then softened again. The hydrogel was imaged using a 3D fluorescent confocal microscope (BC43) using a 2X objective.

Caption: This photo indicates that we can selectively and concurrently micropattern our hydrogel for use in tissue engineering, a big challenge of natural biomaterials. Indeed, this technique is important to precisely create tissues or disease models with different stiffnesses on the same hydrogel. This micropatterning technique also allows us to tether bioactive ligands or peptides to trigger biological activities of encapsulated cells within the hydrogel. Each pixel of the logo is 35 μm.