Page 90 - MSAM-3-1

Materials Science in Additive Manufacturing Bioactive hydrogels for 3D bioprinting

H-BBG15 and H-BBG20 demonstrate improved printing H-BBG15, and H-BBG20. The figure shows the highest
outcomes, with more consistent geometries and closer to shape fidelity at 25, 25, 30, and 35°C for H-BBG0,
square pores. These differences in print outcomes can be H-BBG10, H-BBG15, and H-BBG20, respectively. We
attributed to the rheological behavior of the biomaterial compared the printability of these four biomaterial inks
inks. Note that the 3D-printed H-BBG0 scaffold, despite by using the highest shape fidelity for each of them. The
obvious irregularities in pore geometry, still maintains the addition of BBG appears to increase the printability, with
mesh structure. As shown in Figures 4 and 5, the H-BBG0 higher BBG concentrations improving the biomaterial ink’s
ink exhibits the lowest viscosity. From Figure 9, it becomes printability, i.e., its ability to form and retain the desired
evident that the lower viscosity leads to the higher surface geometry. H-BBG20 showed a slight improvement in
tension of the hydrogel after printing, contributing to shape fidelity compared to H-BBG15, while both samples
8
more fusion between adjacent layers and resulting in showed significant improvement (P <0.05) in shape fidelity
lower shape retention and formation of more deviated compared to H-BBG10 and H-BBG0 (plain hydrogel). The
pore shapes at the scaffold corners. The notable viscosity printability improvement is attributed to BBG’s effect on
increase in H-BBG15 and H-BBG20 inks correlates with improving the biomaterial ink’s rheological properties.
improved shape fidelity at their respective near-optimal Table 1 provides data on viscosity, shape fidelity, and
temperatures of 30°C and 35°C. Thus, the higher BBG filament uniformity obtained from various tests at 25,
content in H-BBG-15 and H-BBG20 inks contributes to 30, 35, and 40°C for H-BBG0, H-BBG10, H-BBG15, and
significant enhancement in the hydrogel printability. H-BBG20, with the data represented by the mean and
standard deviation for each set of temperature and BBG
Figure 10 depicts the shape fidelity of 3D-printed content. A plot of shape fidelity versus viscosity based
scaffolds at various nozzle (ink) temperatures (not just on the mean values for all the data points is shown in
the most desirable temperatures) for H-BBG0, H-BBG10,

Table 1. Viscosity, shape fidelity and filament uniformity for
A
each biomaterial ink composition extruded and printed at
25, 30, 35, and 40℃
Biomaterial 25°C 30°C 35°C 40°C
ink Mean SD Mean SD Mean SD Mean SD
H-BBG0
Vis 6.01 2.09 2.33 1.04 0.33 0.03 0.19 0.01
SF 0.57 0.29 0.11 0.04 - - - -
FU 0.89 0.03 - - - - - -
H-BBG10
Vis 6.34 2.57 0.44 0.21 0.32 0.02 0.25 0.01
B
SF 0.7 0.22 0.16 0.08 0.12 0.08 0.33 0.22
FU 0.89 0.02 - - - - - -
H-BBG15
Vis 14.12 6.47 4.88 0.95 0.37 0.02 0.19 0.01
SF 0.47 0.17 0.75 0.17 0.67 0.16 0.22 0.12
FU - - 0.93 0.02 - - - -
H-BBG20
Vis 158.15 99.64 15.74 10.08 4.68 2.09 0.58 0.05
SF 0.5 0.7 0.49 0.15 0.83 0.07 0.57 0.12
FU - - - - 0.94 0 - -
Notes: The viscosity (Vis, unit: Pa·s) and shape fidelity (SF) for each
biomaterial ink composition extruded and printed at 25, 30, 35, and
Figure 8. Filament width (A) and filament uniformity (B) obtained for 40°C are given. The filament uniformity (FU) for each sample is
printed filaments at various extrusion pressures with the temperature of reported at the near-optimal extrusion temperature and pressure: 25°C
best extrudability identified for the hydrogel biomaterial ink incorporating and 50 kPa for H-BBG0 and H-BBG10; 30°C and 100 kPa for H-BBG0;
different BBG content. and 35°C and 100 kPa for H-BBG20.
Abbreviation: BBG: Bioactive borate glass. Abbreviation: H-BBG: Hydrogel-bioactive borate glass.

Volume 3 Issue 1 (2024) 11 https://doi.org/10.36922/msam.2845