130
properties of the printed structures in vitro. Similarly, Kolesky et al. described the
use of Pluronic F127 and GelMA laden with human neonatal dermal fibroblasts
(HNDFs), to print vascular networks [28]. In that experiment, the microvascular
channel was formed similar to the strategy employed by Wu et al. [51]. After the
evacuation of Pluronic F127, the GelMA was photopolymerized before HUVECs
were seeded into the channels. The group showed high cell viability of HNDFs and
HUVECs, 1 week after printing.
Kolesky et al. described the use of “vascular ink,” which contained Pluronic
F127 and thrombin mixtures, and “cell ink,” which contained fibrinogen and gelatin
mixtures, in the construction of a thick vascular network (>10 mm) [29]. The group
demonstrated the perfusability of the vascular constructs in a complex microenvironment. The vascular channels, which were lined by HUVECs, were incorporated
into a human mesenchymal cell (hMSC) printed network. After 6 weeks, the group
described the osteogenic differentiation of the hMSCs. This experiment demonstrated the development of thick vascular network using 3D printing technology.
Vascular Graft Creation (Table 5.2)
Various fabrication technologies have been investigated, to improve oxygen and
nutrients delivery in printed vascular grafts. Wang et al. developed a novel bioink
delivery system to fabricate vascular tissue (diameter 3–5 mm) with a strong outer
layer coated with synthetic polymer, to provide mechanical protection for the inner
core [52]. The inner core was coated with a cell-laden hydrogel, to provide an organized microenvironment that would support cellular metabolism. In the experiment,
a double nozzle system was used to deposit the polyurethane and adipose-derived
stem cell (ADSC) bioink. The thickness of the outer layer had a huge impact on the
geometry of the construct, the formation of the interface between the two layers,
and the viability of the printed cells. This study optimized these parameters to create
robust vascular constructs and drew attention to the evaluation of perfusion ability
of printed vascular channels.
Besides the in vitro vascular graft engineering studies described here, a preclinical study was conducted by Fukunishi et al. [14]. The group performed a thoracic
inferior vena cava (IVC) interposition graft implantation surgery in vivo, using a 3D
printed graft composed of polyglycolic acid (PGA) and poly(L-lactide-co-εcaprolactone) (PLCL) scaffolds. The study involved a 6-month follow-up period.
No significant difference in mechanical properties was noted between the tissueengineered vascular graft and the native IVC. The extracellular content of the
TEVG, examined at 6-month time points, demonstrated that elastic and collagen
levels were comparable to native IVC. This study validated the feasibility of 3D
printing patient-specific vascular constructs to treat vascular disease. Further animal
studies are warranted for the development of clinically relevant and patient-specific
3D printed vascular constructs.
E. Yeung et al.
properties of the printed structures in vitro. Similarly, Kolesky et al. described the
use of Pluronic F127 and GelMA laden with human neonatal dermal fibroblasts
(HNDFs), to print vascular networks [28]. In that experiment, the microvascular
channel was formed similar to the strategy employed by Wu et al. [51]. After the
evacuation of Pluronic F127, the GelMA was photopolymerized before HUVECs
were seeded into the channels. The group showed high cell viability of HNDFs and
HUVECs, 1 week after printing.
Kolesky et al. described the use of “vascular ink,” which contained Pluronic
F127 and thrombin mixtures, and “cell ink,” which contained fibrinogen and gelatin
mixtures, in the construction of a thick vascular network (>10 mm) [29]. The group
demonstrated the perfusability of the vascular constructs in a complex microenvironment. The vascular channels, which were lined by HUVECs, were incorporated
into a human mesenchymal cell (hMSC) printed network. After 6 weeks, the group
described the osteogenic differentiation of the hMSCs. This experiment demonstrated the development of thick vascular network using 3D printing technology.
Vascular Graft Creation (Table 5.2)
Various fabrication technologies have been investigated, to improve oxygen and
nutrients delivery in printed vascular grafts. Wang et al. developed a novel bioink
delivery system to fabricate vascular tissue (diameter 3–5 mm) with a strong outer
layer coated with synthetic polymer, to provide mechanical protection for the inner
core [52]. The inner core was coated with a cell-laden hydrogel, to provide an organized microenvironment that would support cellular metabolism. In the experiment,
a double nozzle system was used to deposit the polyurethane and adipose-derived
stem cell (ADSC) bioink. The thickness of the outer layer had a huge impact on the
geometry of the construct, the formation of the interface between the two layers,
and the viability of the printed cells. This study optimized these parameters to create
robust vascular constructs and drew attention to the evaluation of perfusion ability
of printed vascular channels.
Besides the in vitro vascular graft engineering studies described here, a preclinical study was conducted by Fukunishi et al. [14]. The group performed a thoracic
inferior vena cava (IVC) interposition graft implantation surgery in vivo, using a 3D
printed graft composed of polyglycolic acid (PGA) and poly(L-lactide-co-εcaprolactone) (PLCL) scaffolds. The study involved a 6-month follow-up period.
No significant difference in mechanical properties was noted between the tissueengineered vascular graft and the native IVC. The extracellular content of the
TEVG, examined at 6-month time points, demonstrated that elastic and collagen
levels were comparable to native IVC. This study validated the feasibility of 3D
printing patient-specific vascular constructs to treat vascular disease. Further animal
studies are warranted for the development of clinically relevant and patient-specific
3D printed vascular constructs.
E. Yeung et al.