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RESEARCH ARTICLE

A novel bioactive PEEK/HA composite with controlled

3D interconnected HA network

Mohammad Vaezi and Shoufeng Yang
*
Faculty of Engineering & the Environment, University of Southampton, SO17 1BJ, UK

Abstract: Polyetheretherketone (PEEK) is a high-performance thermoplastic biomaterial which is currently used in a
variety of biomedical orthopaedic applications. It has comparable tensile and compressive strength to cortical bone with
favourable biocompatibility. However, natural grade PEEK-OPTIMA has shown insufficient bioactivity and limited
bone integration. Bioactive PEEK composites (e.g., PEEK/calcium phosphates or Bioglass) and porous PEEK have been
used to improve bone-implant interface of PEEK-based devices, but the bioactive phase distribution or porosity control
is poor. In this paper, a novel method is developed to fabricate a bioactive PEEK/hydroxyapatite (PEEK/HA) composite
with a unique configuration in which the HA (bioactive phase) distribution is computer-controlled within a PEEK
matrix. This novel process results in complete interconnectivity of the HA network within a composite material,
representing a superior advantage over alternative forms of product. The technique combines extrusion freeforming, a
type of additive manufacturing (AM), and compression moulding. Compression moulding parameters, including pres-
sure, temperature, dwelling time, and loading method together with HA microstructure were optimized by
experimentation for successful biocomposite production. PEEK/HA composites with a range of HA were produced us-
ing static pressure loading to minimise air entrapment within PEEK matrix. In addition, the technique can also be em-
ployed to produce porous PEEK structures with controlled pore size and distribution.
Keywords: polyetheretherketone (PEEK); additive manufacturing (AM); bioactive PEEK/HA composite

*Correspondence to: Shoufeng Yang, Faculty of Engineering & the Environment, University of Southampton, SO17 1BJ, UK; Email:
s.yang@soton.ac.uk

Received: May 25, 2015; Accepted: June 17, 2015; Published Online: July 2, 2015
Citation: Vaezi M and Yang S F, 2015, A novel bioactive PEEK/HA composite with controlled 3D interconnected HA network. In-
ternational Journal of Bioprinting, vol.1(1): 66–76. http://dx.doi.org/10.18063/IJB.2015.01.004.

1. Introduction requirements and has been used in multiple clinical
P omaxillofacial reconstruction. Despite possessing fa-
applications including spinal cage fusion and crani-
olyetheretherketone (PEEK) is a semi-crystal-
line thermoplastic with excellent fibroblasts and
vourable biomaterial properties as described above,
osteoblasts biocompatibility, and with desirable
mechanical properties such as strength, stiffness, PEEK is relatively bioinert, demonstrating poor
and great thermal stability. Elastic modulus of PEEK osteointegration following implantation. Lack of bio-
is similar to that of cortical bone, which can reduce integration can result in graft migration, and failure of
stress shielding following implantation. It is also radi- the reconstructive procedure. Three main approaches
olucent which permits radiographic assessment. The are being developed to enhance bone apposition of
combination of these optimal properties has made PEEK-based implants for orthopaedic application:
PEEK of great potential for orthopaedic application. • Incorporating bioactive materials such as cal-
Medical grade PEEK-OPTIMA has been developed to cium phosphates into PEEK to improve the
meet the US Food and Drug Administration’s (FDA) bone-implant apposition,

A novel bioactive PEEK/HA composite with controlled 3D interconnected HA network. © 2015 Mohammad Vaezi and Shoufeng Yang. This is an
Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License
(http://creativecommons.org/licenses/by-nc/4.0/), permitting all non-commercial use, distribution, and reproduction in any medium, provided the original
work is properly cited.
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