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Owen, et al.
by the alginate beads are smooth and form an The compressive modulus of the polyHIPE
open porosity with a similar morphology to the decreased as alginate bead content increased
polyHIPE surface that cures against air on the top (Figure 3). A linear relationship was observed
of the emulsion. between wt% of alginate beads and compressive
moduli (R = 0.998).
2
3.2 Porogen leaching of polyHIPEs decreases
the compressive modulus 3.3 Porogen leached polyHIPE had superior
mineralized matrix distribution
A Seeding efficiency was significantly higher on
the 100 wt% alginate porogen leached polyHIPE
scaffolds in comparison to plain scaffolds, with
approximately 30% higher metabolic activity
observed on day 0 (P < 0.05, Figure 4A). By day
14, metabolic activity was still significantly higher
(100 wt% vs. plain, P < 0.05). Calcium deposition
B C by ARS staining was greatest on the plain scaffold
in comparison to both porogen leached scaffolds
on day 7 (P < 0.05), but there was no significant
difference by day 14 (Figure 4B). Collagen
deposition by DR80 staining on the 50 wt%
polyHIPEs was significantly lower on day 7 in
comparison to 100 wt% polyHIPEs (P < 0.05),
D E
with no significant differences between any group

F G

Figure 2. (A) Alginate bead size distribution after
sieving. Low (B, D, F, scale bars 500 μm) and
high (C, E, G, scale bars 200 μm) magnification
scanning electron microscopy images of (B and C)
plain polymerized high internal phase emulsions Figure 3. Compressive modulus of polymerized
(polyHIPEs), (D and E) 50 wt% alginate bead high internal phase emulsions (polyHIPEs) at
polyHIPEs, and (F and G) 100 wt% alginate bead different alginate bead incorporation. Porogen
polyHIPEs. Large macropores left by alginate leaching with alginate significantly reduced the
beads clearly visible in the 50 and 100 wt% compressive moduli at 50 wt% (P < 0.05) and 100
polyHIPEs (D-G), with interconnection between wt% (P < 0.001) in comparison to plain polyHIPEs
macro pores occurring at the highest wt% (G). (n = 4).

International Journal of Bioprinting (2020)–Volume 6, Issue 2 105