ENGINEERING 2D AND 3D CELLULAR MICROENVIRONMENTS USING LASER DIRECT WRITE - 3D Bioprinting and Nanotechnology in Tissue Engineering and Regenerative Medicine - page 118

FIGURE 5.6
Examples of microbeads fabricated and patterned with LDW in a single step. Patterns are shown with microbead
diameter sizes of (a) 150 m m, (b) 350 m m with human breast cancer cells, (c) 500 m m, and (d) multiple bead sizes
in a single pattern with mouse embryonic stem cells. Scale bars are 200 m m. Bead size is controlled by adjusting
the laser beam diameter, and cell density is adjusted via the cell density on the print ribbon. Microbeads can be
patterned into custom configurations to study spatially sensitive aspects of the microenvironment.
Processing of LDW patterned and fabricated microbeads to microcapsules is current and ongo-
ing work. Figure 5.7 shows preliminary results of processed LDW microbeads into chitosan-alginate
microcapsules. It appears that processed microcapsules retain initial bead position on the patterned
substrate. The advantage of these capsules fabricated by LDW is that they can be placed accurately
(within 2% of their target spacing). By exchanging the ribbon during printing, coculture studies can
examine how signaling occurs from capsule to capsule. The spatial precision afforded by LDW allows
fabrication of capsules or beads that are approximately touching. This suggests future applications
where beads could be placed overlapping and processed to create hollow complex structures, or any
planar geometry.