3. A UV light source (365 nm) is used to induce the photopolymerization. A set of optics are placed in front of the UV light
source to collimate and project the UV light to the DMD chip.
It is recommended to illuminate the entire DMD chip with
even light intensity. A homogenizer can be used to modulate
the light intensity.
4. A set of projection optics are placed below the DMD chip to
project the digital patterns to the fabrication reservoir. The
magnification of the projection optics dictates the resolution
and overall dimension of the printed structures.
5. A motorized syringe pump system is connected to the fabrication reservoir to add and remove the prepolymer solution.
6. A computer is used to control the DMD, the UV light source,
the syringe pump system, and the motorized stage. A software
is developed to synchronize the control of all the components.
7. 3D models can be built in computer-aided-design (CAD) software or from computed tomography (CT) and magnetic resonance imaging (MRI) scans.
8. The digital masks are sliced from the 3D models and fed into
the DMD continuously to alter the optical pattern projected
onto the prepolymer solution.
9. 3D printing can be realized by simultaneously moving the stage
and updating the digital masks which are both controlled by
the computer.
3.6 3D Bioprinting of
Vascularized Tissues
1. Design a set of digital masks according to the example provided
in Fig. 1, suitable for the fabrication of tissues with gradient
channel widths (ranging from 50 μm to 250 μm), mimicking
the branching structure of a vasculature network.
2. Digest HUVECs and 10T1/2 s by 0.05% trypsin-EDTA and
0.25% trypsin-EDTA, respectively (see Note 12).
3. Mix these two cell types at a ratio of 50:1 (40 million/mL
HUVECs and 800,000/mL 10T1/2 s) (see Note 13).
4. Prepare prepolymer A by dissolving 5% (w/v) GelMA and
0.15% (w/v) LAP in DPBS (see Note 14).
5. Prepare prepolymer B by dissolving 5% (w/v) GelMA, 2%
(w/v) GM-HA, and 0.15% (w/v) LAP in DPBS.
6. Filter the prepolymer A and B solutions with a 0.22 μm sterile
filter.
7. Load prepolymer A onto the fabrication stage and the first
mask on the left in Fig. 1 onto the DMD chip.
8. Expose the UV light for 15 s to fabricate the base layer. Remove
the unpolymerized part of the prepolymer A and wash
with DPBS.
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source to collimate and project the UV light to the DMD chip.
It is recommended to illuminate the entire DMD chip with
even light intensity. A homogenizer can be used to modulate
the light intensity.
4. A set of projection optics are placed below the DMD chip to
project the digital patterns to the fabrication reservoir. The
magnification of the projection optics dictates the resolution
and overall dimension of the printed structures.
5. A motorized syringe pump system is connected to the fabrication reservoir to add and remove the prepolymer solution.
6. A computer is used to control the DMD, the UV light source,
the syringe pump system, and the motorized stage. A software
is developed to synchronize the control of all the components.
7. 3D models can be built in computer-aided-design (CAD) software or from computed tomography (CT) and magnetic resonance imaging (MRI) scans.
8. The digital masks are sliced from the 3D models and fed into
the DMD continuously to alter the optical pattern projected
onto the prepolymer solution.
9. 3D printing can be realized by simultaneously moving the stage
and updating the digital masks which are both controlled by
the computer.
3.6 3D Bioprinting of
Vascularized Tissues
1. Design a set of digital masks according to the example provided
in Fig. 1, suitable for the fabrication of tissues with gradient
channel widths (ranging from 50 μm to 250 μm), mimicking
the branching structure of a vasculature network.
2. Digest HUVECs and 10T1/2 s by 0.05% trypsin-EDTA and
0.25% trypsin-EDTA, respectively (see Note 12).
3. Mix these two cell types at a ratio of 50:1 (40 million/mL
HUVECs and 800,000/mL 10T1/2 s) (see Note 13).
4. Prepare prepolymer A by dissolving 5% (w/v) GelMA and
0.15% (w/v) LAP in DPBS (see Note 14).
5. Prepare prepolymer B by dissolving 5% (w/v) GelMA, 2%
(w/v) GM-HA, and 0.15% (w/v) LAP in DPBS.
6. Filter the prepolymer A and B solutions with a 0.22 μm sterile
filter.
7. Load prepolymer A onto the fabrication stage and the first
mask on the left in Fig. 1 onto the DMD chip.
8. Expose the UV light for 15 s to fabricate the base layer. Remove
the unpolymerized part of the prepolymer A and wash
with DPBS.
168
Wei Zhu et al.