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grafts, including pore dimension and distribution, play an important role in the
active cell regeneration process in terms of nutrient/oxygen exchange and metabolite waste removal. Furthermore, 3D printed tissue and vascular constructs can be
tailor-made to patient-specific organ tissue morphologies using various image mapping techniques like X-ray, magnetic resonance imaging (MRI), or computed
tomography (CT) [19]. The extreme precision and delicate cell/biomaterial handling algorithms used in 3D bioprinting allow for microvascular construction with
native-like cellular signaling.
In this chapter we will discuss different 3D printing approaches, including inkjet,
extrusion, laser and scaffold-free methods, and their current applications in fabrication of microvascular network (diameter <1 mm) and vascular graft (diameter
≥1 mm).
5.2 Methodology
In each method section, the discussion of the application is divided into microvascular channel creation and vascular graft creation, with tables corresponding to
each. Table 5.1 is for microvascular channel creation, and Table 5.2 is vascular graft
creation.
5.2.1 Inkjet-Based Printing
5.2.1.1 Principle (Fig. 5.1)
Inkjet printing technology was developed in the 1950s. In 2D printing, materials are
first loaded as liquids into a nozzled chamber. During printing, the materials are
pushed out from a syringe-like device, forming a stream of droplets due to PlateauRayleigh instability. The droplets are then charged by an electrode and deflected by
an electric field to print at a desired position on the substrate. In 3D inkjet printing,
the same principles are applied. The printing materials, which can include a hydrogel scaffold, living cells, or a mixture of both, are precisely deposited as droplets
[19]. Different types of driving energy technologies have been described, including
thermal, piezoelectric, and electrostatic modalities. In thermal inkjet systems, rapid
heat energy provides the driving pressure for the bioink droplets, whereas in piezoelectric systems, polycrystalline ceramics promote the conversion of electric energy
to mechanical energy, to allow for particle deposition. The nozzle is critical for
droplet loading in inkjet systems. However, the shear forces exerted by the nozzle
on the printed droplets can impact cell viability and the chemical properties of the
bioink. This necessitated the development of a droplet-on-demand system,
introduced to minimize such damages, using a micro-valve to precisely deliver the
bioink [7].
E. Yeung et al.
grafts, including pore dimension and distribution, play an important role in the
active cell regeneration process in terms of nutrient/oxygen exchange and metabolite waste removal. Furthermore, 3D printed tissue and vascular constructs can be
tailor-made to patient-specific organ tissue morphologies using various image mapping techniques like X-ray, magnetic resonance imaging (MRI), or computed
tomography (CT) [19]. The extreme precision and delicate cell/biomaterial handling algorithms used in 3D bioprinting allow for microvascular construction with
native-like cellular signaling.
In this chapter we will discuss different 3D printing approaches, including inkjet,
extrusion, laser and scaffold-free methods, and their current applications in fabrication of microvascular network (diameter <1 mm) and vascular graft (diameter
≥1 mm).
5.2 Methodology
In each method section, the discussion of the application is divided into microvascular channel creation and vascular graft creation, with tables corresponding to
each. Table 5.1 is for microvascular channel creation, and Table 5.2 is vascular graft
creation.
5.2.1 Inkjet-Based Printing
5.2.1.1 Principle (Fig. 5.1)
Inkjet printing technology was developed in the 1950s. In 2D printing, materials are
first loaded as liquids into a nozzled chamber. During printing, the materials are
pushed out from a syringe-like device, forming a stream of droplets due to PlateauRayleigh instability. The droplets are then charged by an electrode and deflected by
an electric field to print at a desired position on the substrate. In 3D inkjet printing,
the same principles are applied. The printing materials, which can include a hydrogel scaffold, living cells, or a mixture of both, are precisely deposited as droplets
[19]. Different types of driving energy technologies have been described, including
thermal, piezoelectric, and electrostatic modalities. In thermal inkjet systems, rapid
heat energy provides the driving pressure for the bioink droplets, whereas in piezoelectric systems, polycrystalline ceramics promote the conversion of electric energy
to mechanical energy, to allow for particle deposition. The nozzle is critical for
droplet loading in inkjet systems. However, the shear forces exerted by the nozzle
on the printed droplets can impact cell viability and the chemical properties of the
bioink. This necessitated the development of a droplet-on-demand system,
introduced to minimize such damages, using a micro-valve to precisely deliver the
bioink [7].
E. Yeung et al.