Bioprinting Hard Tissues using PCL (Polycaprolactone)

Overview

PCL (polycaprolactone) is a thermoplastic polymer that allows for enhanced control over the mechanical properties of 3D printed structures. It is specifically developed and optimized for bioprinting of 3D structures. PCL may be used on its own or printed with matrix bioinks such as gelatin methacrylate. Follow this protocol for bioprinting constructs using PCL.

The recommended preparation provided in the instructions below yields an easily printable biomaterial that creates reproducible 3D printed constructs; however, preparation can be modified by users to suit their needs.

Materials

• PCL
• MT27 Metal needle
• Metal Syringe (5 mL or 10 mL)
• Petri dish or well plate for printing
  • Sandpaper, painters tape or roughened printing surface for first layer adhesion

Methods for Bioprinting Hard Tissues using PCL

Material Prep: Thermal Method

1. Load PCL into metal syringe.
   1. Note: use a metal funnel to facilitate material loading into the metal syringe.
   2. Note: we recommend filling the entire metal syringe to the top with PCL pellets so that when melted the syringe will contain roughly 4 mL of material.
2. Screw the metal tip on the metal syringe.
3. Set your Allevi CORE™ extruder temperature to 110˚C.
4. Load your metal syringe into the extruder.
5. Wait for approximately 20 min until the PCL melts before starting to print.

Print Settings: Thermal Method

Speed (mm/s)	Layer height (mm)	Nozzle Diam (mm)	Gauge	Pressure (PSI)	Print Temperature (°C)
1.0	0.1	0.233	MT30	100	110
1.0	0.1	0.335	MT27	100	110
2.0	0.15	0.437	MT25	100	120
3.0	0.15	0.564	MT23	100	100
3.0	0.15	0.400	FMN400	100	100

Troubleshooting

1. If there is stringing observed during print, try lowering the print speed, using a nozzle with smaller I.D., or increasing the extruder temperature.
2. If the printed construct is deforming and lifting off from the print surface, make sure to set the bed temperature to 30-40°C.
3. It may be necessary to firmly attach the petri dish to the print bed using tape so that it does not shift position during printing.
4. If the printed structure is taller than it is wide, it is more likely that it will detach from the print surface. To prevent this, use a textured print surface such as the sandpaper printing surface.

We hope you found this protocol helpful for bioprinting hard tissues using PCL! Click here to learn how to prepare and bioprint solubilized PCL, or click here for more bioprinting protocols.