Compositions and Methods for 3D Printing of Calcium Phosphate Cement Composite Scaffolds

Background The global market size for bone grafts and substitutes is estimated to be about $2.8B, with more than 2 million bone graft procedures performed worldwide each year. Although bone autografts and allografts are widely used, they suffer fro…

Background

The global market size for bone grafts and
substitutes is estimated to be about $2.8B, with more than 2 million bone graft
procedures performed worldwide each year. Although bone autografts and
allografts are widely used, they suffer from a high risk of infections and
rejection by the immune system. Additive manufacturing using
hydroxyapatite-based scaffolds has been proposed as an alternative that can generate
customized 3D-printed patient-specific implantable scaffold structures.
However, present processes are incapable of printing with high resolution.
Furthermore, the amount of ceramic material within many inks is limited to less
than about 30% by the weight of the printing ink, which reduces elasticity and
structural strength. Furthermore, elevated temperatures are required for
printing.

Invention Description

ADASRI researchers have developed new compositions
of matter (inks) and associated 3D printing methods that allow room-temperature
printing of high-resolution and mechanically stronger composite scaffold
structures. The 3D printing inks include calcium phosphate cement (CPC) powders
and a biocompatible polymer. Upon printing in an aqueous environment, the
polymer material hardens first and provides initial strength for the composite
structure as well as flexibility. A self-setting reaction of the co-deposited
CPC materials in the aqueous solution then form, in-situ, a cement, such as hydroxyapatite,
which then hardens to produce the final composite structure.

Potential Applications

The present invention is ideally suited for use to 3D-print customizable

scaffolds for  

  • Patient-specific implantable structures that promote bone regeneration
  • e.g. Craniofacial implants (as flat and irregular bone structures), including alveolar and calvaria bone types
  • e.g. Other trabecular and cortical bone implants
  • Research applications: biological testing materials, bone disease modeling

Benefits and Advantages

  • High cement powder mass loading up to 75% produces structures with increased strength.
  • High-resolution printing: structures with feature sizes less than 100 mm can be formed, allowing for the printing of a wider range of bone-implant structures.     
  • Room-temperature process: printing eliminates cooling-induced stresses in structures.    
  • Biocompatible: printed structures are osteoconductive, and support cell attachment and growth.
  • Reliable printing: use of an aqueous bath reduces nozzle clogging.
  • Compatible with different deposition techniques, including syringes & pneumatic dispensers, and filament extruders.
Calcium phosphate cement
Fabrication and structure of a 3D-printed