Case Study: Hydroxyapatite and PCL


Hydroxyapatite and polycaprolactone blends have been previously investigated as scaffolds for bone tissue engineering [1]. In addition to its biocompatibility, hydroxyapatite offers osteoconductive properties. However, with a high melting temperature and insolubility in water, hydroxyapatite presents challenges for extrusion bioprinting. When mixed with polycaprolactone, which exhibits a low melting point, the blended materials can be printed together [1]. Below are sample print parameters for a hydroxyapatite and polycaprolactone blend with the Allevi 1.

First, polycaprolactone (PCL) was melted on a glass plate at 100°C. Very carefully, 20% (w/v) hydroxyapatite was mixed into the PCL. Then, this mixture was loaded into an allevi metal 10 ml BD syringe. A metal 27 gauge fisnar needle was placed onto the tip of the syringe and loaded into the first extruder of the Allevi 1. The extruder was then heated to 120°C. A lattice, imaged below, was completed at a pressure of 100 PSI with an approximate resolution of 0.3 – 0.4 mm.

Figure 1:: Printed lattice with above parameters.

Figure 1:: Printed lattice with above parameters.

*Critical step: Your needle can have significant effects on print settings. Be sure to use the suggested needle type or re-characterize print parameters.
Speed (mm/s) Layer Height (mm) Nozzle Diam (mm) Gauge Pressure (psi) Print Temp (C)
0.5 0.2 0.3 27 Tapered 100 120

If you are interested in printing bone, you can check out our Bone Bioink Kit in the Allevi Shop.


  1. Park, Su A. Fabrication of porous polycaprolactone/hydroxyapatite (PCL/HA) blend scaffolds using a 3D plotting system for bone tissue engineering. Bioprocess Biosyst Eng. 2011 (34). pp. 505-513.