1 3 D printing of PEEK / HAp scaffold for medical bone implant 1 2

11 The major drawback associated with PEEK implants is their biologically inert surface, which caused unsatisfactory 12 cellular response and poor adhesion between the implants and surrounding soft tissues against proper bone growth. In this 13 study, polyetheretherketone (PEEK) was incorporated with Calcium Hydroxyapatite (cHAp) to fabricate a PEEK/cHAp 14 biocomposite, using the fused deposition modeling (FDM) method and a surface treatment strategy to create microporous 15 architectures onto the filaments of PEEK lattice scaffold. Also, nanostructure and morphological tests of the PEEK-cHAp 16 biocomposite were modeled and analyzed on the FDM-printed PEEK-cHAp biocomposite sample to evaluate its 17 mechanical and thermal strengths as well as in vitro cytotoxicity via a scanning electron microscope (SEM). A technique 18 was used innovatively to create and investigate the porous nanostructure of the PEEK with controlled pore size and 19 distribution to promote cell penetration and biological integration of the PEEK-cHAp into the tissue. In vivo tests 20 demonstrated that the surface-treated micropores facilitated the adhesion of newly regenerated soft tissues to form tight 21 implant-tissue interfacial bonding between the cHAp and PEEK. The results of the cell culture depicted that PEEK/HAp 22 exhibited better cell proliferation attachment spreading and higher alkaline phosphatase activity than PEEK alone. Apatite 23 islands formed on the PEEK/HAp composite after immersion in simulated body fluid of Dulbecco's Modified Eagle 24 Medium (DMEM) for 14 days and grew continuously with more or extended periods. The microstructure treatment of the 25 crystallinity of PEEK was comparatively and significantly different from the PEEK-cHAp sample, indicating a better 26 treatment of PEEK/cHAp. The in vitro results obtained from the PEEK-cHAp biocomposite material showed its 27 biodegradability and performance suitability for bone implants. This study has potential applications in the field of 28 biomedical engineering to strengthen the conceptual knowledge of FDM and medical implants fabricated from PEEK29 cHAp biocomposite materials. 30 31