Fabrication of Biocomposite Scaffolds Based on Multidoped Calcium Hydroxyapatite and a Biodegradable Polymer Using 3D Printing

Abstract

Introduction: Due to the limitations of bone grafts, bone tissue engineering has been developed, involving the application of scaffolds – temporary 3D cell carriers. Calcium hydroxyapatite (HAP) is used as a biomaterial for scaffolds because of its similarity to biological apatite. The crystal structure of HAP allows substitution with strontium, magnesium, zinc, and copper ions, which enhance angiogenesis, proliferation, and osteogenic cell differentiation, while also providing antimicrobial effects. However, the brittleness of ceramic materials prevents their use at load-bearing sites, making it desirable to develop biocomposite materials that mimic bone tissue.

 Aim: This study aims to develop biocomposite scaffolds from multi-doped HAP and biodegradable photo-crosslinkable polymer polyethylene glycol diacrylate (PEGDA) using masked stereolithography (mSLA) 3D printing.

 Materials and Methods: Hydroxyapatite powder was doped during hydrothermal synthesis with 2 mol.% Sr, 3 mol.% Mg, 0.4 mol.% Zn, and 0.4 mol.% Cu. The morphology, elemental, and phase composition of the particles were determined using SEM, EDS, and XRD analyses. Biocomposite scaffolds were obtained by mixing different amounts of multi-doped HAP (0 wt.%, 5 wt.%, and 10 
wt.%) into the PEGDA-based ink and 3D printing them, after which the structure and compressive strength of the obtained scaffolds were compared.

 Results: Biocomposite 3D-printed scaffolds based on HAP and PEGDA were successfully fabricated using the mSLA method. Scaffolds with 5% HAP exhibited improved mechanical properties, while 10% HAP caused excessive crosslinking and reduced performance.

 Conclusion: The masked SLA method is suitable for fabricating biocomposite scaffolds, and future work will explore alternative polymer matrices in order to allow higher HAP particle loading.