PEGDA Bioprinting

Overview

Poly(ethyelene glycol) diacrylate, or PEGDA, is a PEG-based hydrogel that reacts and crosslinks in the presence of LAP photoinitiator and Allevi blue light technology. The recommended preparation provided in the user instruction below yields a streamlined matrix bioink that supports 3D printed cell-laden constructs. However, preparation can be modified by users to suit their needs. Follow this step-by-step process for PEGDA bioprinting.

Note: Due to low viscosity, PEGDA solutions can be difficult to work with when bioprinting. For optimal results, we suggest mixing this reagent with a more viscous material.

Materials

• PEGDA
• LAP
• Plastic syringe (5 mL or 10 mL)
• Printing dish of your choice
• Percoll
• Metal or UV-block tips
• Printing dish of your choosing
• 0.45 µm sterile filters (we suggest these)
• Optional: Treated glass (See protocol)

Methods

1. Measure 0.8% w/v LAP concentration and mix in cell media or PBS at 60°C in a light-protected vial. Mix until all LAP is dissolved.
2. Measure 33.33% w/v PEGDA concentration and add to the solution, still in a light-protected vial. Mix at 60°C until all PEGDA is dissolved.
3. Adjust pH of solution from step 2 to 7.4.
4. Filter solution with a 0.45 µm syringe filter under sterile conditions.*
5. Mix solution with Percoll to create a 40% (v/v) Percoll solution.
   • Note: For 5 ml, you will need 3 ml of solution and 2 ml of Percoll.
6. Mix in desired cell concentration in a sterile container.*
7. Load cell-laden bioink into a sterile plastic syringe.
8. Load syringe into Allevi bioprinter.
9. Place the desired printing dish onto the print-bed.
10. Design or upload your CAD file in the Allevi software and use the print settings outlined below. Print your desired structure.
    • Note that this material will need to be combined with some type of support or sacrificial reagent such as pluronic or PCL.

* For prints without cells, step 4 & step 6 may be skipped.

Print Settings

Speed (mm/s)	Layer Height (mm)	Nozzle Diam (mm)	Gauge	Pressure (psi)	Print Temp (C)
4.0	0.3	0.3	30 tapered	3-5	25

Post-print settings

Crosslinking Time (s)	Crosslink Intensity (mW/cm^2)
240	10

Notes

1. Gelation time and gel stiffness can be adjusted by varying the concentration of PEGDA or LAP. For help adjusting print parameters please contact [email protected].
2. A fill volume change of more than 2 ml may affect pressure settings.
3. A lower gauge size or tapered gauge will require lower pressure, while a higher gauge will require higher pressure for extrusion. Lowering the gauge size will also generally lower resolution

We hope that you found this step-by-step guide for PEGDA bioprinting to be helpful! You are now ready to analyze and image your 3D bioprinted structure – click here for post-print analysis protocols.

References

B. D. Fairbanks et. al, “Photoinitiated Polymerization of PEG-diacrylate with lithium phenyl-2,4,6-trimethylbenzoylphosphinate: polymerization rate and cytocompatibility,” Biomaterials, vol. 30, no. 35, pp. 6702-6707, Dec 2009.

Chan V et al. “Three-dimensional photopatterning of hydrogels using stereolithography for long-term cell encapstulation.” Lab Chip. 2010(10) 2062-70.

Lin, Hang et al. “Application of Visible Light-based Projection Stereolithography for Live Cell-Scaffold Fabrication with Designed Architecture.” Biomaterials 2013(34). pp. 331- 39.