Conductive Tissue Bioprinting Protocol

Share on linkedin
Share on facebook
Share on twitter
Share on reddit
Share on whatsapp
Share on linkedin
Share on facebook
Share on twitter
Share on reddit
Share on whatsapp

Overview

3D-Graphene (3DG) is a biocompatible, conductive material utilized for printing electrically stimulated tissues such as cardiac, skeletal muscle and nerve, as well as biocompatible circuits. 3DG is printed at room temperature and can be seeded with cells post-print.

The recommended preparation provided in the user instruction below yields a streamlined printable biomaterial that creates reproducible 3D printed constructs. However, preparation can be modified by users to suit their needs.

Storage and Handling

3DG should be stored in airtight, glass containers in 4˚C. Due to the solvents present in its composition that quickly evaporate, the material should have minimal contact with air. Make sure to protect your eyes and skin while handling it, and do not inhale it. It is recommended to handle it in a fume hood. More information can be found in the material SDS. 

You Will Need

  1. 3 mL Dimension Inx 3D-Graphene
  2. Allevi 5 mL syringe
  3. 14G metal drawing needle
  4. 27G printing needle
  5. Allevi rough printing surface 

Instructions for Use

Printing:

  1. Remove your vial from 4˚C and let it reach room temperature;
  2. The material will look hardened right as it is taken out of the fridge, so wait for it to look fluid before handling it;
  3. Vigorously vortex the material until it is uniform;
    1. NOTE: If it seems that the material solvent is mostly separated from the powder, you may secure your vial to a vortex mixer with tape and leave it on for at least one hour. Mixing your vial for longer periods of time will allow for a better printing experience.  
  4. Use the 14G needle to puncture the vial’s cap and draw your print session quantity (3 mL), without turning the vial upside down to prevent material loss. 3D-Graphene is highly viscous, so loading may take a few minutes. We recommend that you use this vial for only one print session. If you use it for more sessions, make sure to appropriately seal it. It is advisable to switch the punctured cap to a solid cap for better further storage;
  5. After drawing the material, remove the syringe plunger and drawing needle;
  6. Remove the stopper from the plunger and place it in the syringe;
  7. Place the stopper back in the syringe, pushing it with the plunger until it touches and evenly distributes the drawn material in the syringe. Make sure that, while pushing the stopper with the plunger, they do not re-attach;
  8. Place the 27G printing needle and load your Allevi!
  9. Place the adhesive printing surface on your petri dish.

Post-printing:

  1. Let your printed construct sit in a fume hood for at least 2 hours before handling it. Note that prints can be stored indefinitely in airtight glass containers before washing;
  2. Submerge your printed construct in 70% ethanol
 for at least 1 hour. Gentle agitation is 
recommended. Change the ethanol and leave your object submerged for another hour;
  3. Replace the ethanol with PBS (sterile PBS for biological applications), and use it immediately. If you desire to store this object, freeze it at -20 ̊C, – 40 ̊C or -80 ̊C;
  4. If you did not use our dish and your construct fused with your surface, carefully use a razor blade to remove it. If you did use our dish, simply remove your construct while wearing gloves;
  5. If you desire, you may cut your print with scissors, scalpels, biopsy punches, etc.

Cell seeding:

  1. Aspirate any excess liquid from your printed construct, but do not let it dry completely. It should be slightly moist for cell seeding;
  2. 10-15 μL should be seeded in a 5 mm diameter, 1 mm thick printed construct;
  3. Gels can also be injected into bioprinted and washed objects. 

Print Settings

Speed (mm/s) Layer height (mm) Nozzle Diam (mm) Gauge Pressure (psi) Print Temp (°C)
160.20.22710-20 Room Temperature

Applications

Bone tissue: Natural bone is encapsulated in nerves and muscle tissue, so printing 3DG alongside HB can potentially create multi-tissue units.

Cardiac, neural and skeletal muscle tissue: 3DG is great for tissues that require electrical conduction. Because of its conductivity, 3DG can transmit electrical signals that are key for cardiac, neural and skeletal muscle function.

Biocompatible and flexible circuits: print circuits however you want, seed them with cells and run an electrical current for stimulation. 

Warnings

  • Do not store 3DG in liquid form in plastic containers for several hours, or it will dry out. Try to limit any and all air exposure before printing in order to ensure the best printing experience;
  • Printing with needles of higher gauges (smaller nozzle diameters) than the ones provided may cause intermittent clogging;
  • Do not let 3DG in liquid form come into prolonged contact with ferrous metals, it will corrode them. Do not let it come into contact with polyesters or polystyrenes either, it will fuse with them.
  • Do not let 3DG reach temperatures above 70 ̊C, or it will melt.
  • Do not try to sterilize printed constructs with heat, steam, ethylene oxide, or hydrogen peroxide. This material contains methylene chloride, 2-butoxyethanol, and dibutyl phthalate. 
  • For research purposes only. Not for human or clinical use.

References

Jakus et al. Three-Dimensional Printing of High-Content Graphene Scaffolds for Electronic and Biomedical Applications. ACS Nano. 9 (04). 2015.

Share this article

Share on linkedin
Share on facebook
Share on twitter
Share on reddit
Share on whatsapp