Page 184 - IJB-10-5

International Journal of Bioprinting Control nutrients to manipulate fungal growth

Four sample designs, which could be readily fabricated to flow homogeneously throughout the samples and avoid
using our multi-material DIW approach, were tested additional effects of various oxygen contents.
(Figure 4A). The objective of using these designs was to The foraging behavior of the mycelium of P. ostreatus
observe the foraging behavior of mycelium in structures on the four structures showed significant variations
with local variations in nutrient content and to determine and effects of the designs (Figure 4B). These results
if these variations can either promote or inhibit extension are consistent with the growth of mycelium on various
(Design I and Design II) or bridging (Design III and Design agar formulations (Figure 2), where a clear contrast
IV) between different inoculated regions in the structure. in mycelium density can be observed between zones
Each design contained zones of origin (yellow with white of different nutrient levels. When approaching a low-
circles), which were printed using the ink containing nutrient zone (Design I and Design III), the mycelium
liquid mycelium and medium levels of malt and peptone. formed is sparse. As such, both the extension (Design
After incubation, the mycelium grew from the zones of I) and bridging (Design III) of mycelium are inhibited.
origin and extended into the other zones. The prints were This results in a clear contrast between mycelium at the
intentionally designed to be porous, in order to allow air zones of origin and the low-nutrient zones. This contrast

Figure 4. Local variations in nutrients on a 2D surface guides the growth and foraging behavior of mycelium of P. ostreatus and G. lucidum. (A) Schematics of
design of 3D-printed fungal-based engineered living materials (ELMs) detailing the different constituent materials. Growth of mycelium of (B) P. ostreatus
and (C) G. lucidum on the 3D-printed substrates with zones containing varying concentrations of malt, peptone, and liquid mycelium, respectively. Scale
bars: 20 mm.

Volume 10 Issue 5 (2024) 176 doi: 10.36922/ijb.3939