Characterization of a composite polylactic acid-hydroxyapatite 3D-printing filament for bone-regeneration

Abstract

Autologous cancellous-bone grafts are the current gold standard for therapeutic interventions in which bone-regeneration is desired. The main limitations of these implants are the need for a secondary surgical site, creating a wound on the patient, the limited availability of harvest-safe bone, and the lack of structural integrity of the grafts. Synthetic, resorbable, bone-regeneration materials could pose a viable treatment alternative, that could be implemented through 3D-printing. We present here the development of a polylactic acid-hydroxyapatite (PLA-HAp) composite that can be processed through a commercial-grade 3D-printer. We have shown that this material could be a viable option for the development of therapeutic implants for bone regeneration. Biocompatibility in vitro was demonstrated through cell viability studies using the osteoblastic MG63 cell-line, and we have also provided evidence that the presence of HAp in the polymer matrix enhances cell attachment and osteogenicity of the material. We have also provided guidelines for the optimal PLA-HAp ratio for this application, as well as further characterisation of the mechanical and thermal properties of the composite. This study encompasses the base for further research on the possibilities and safety of 3D-printable, polymer-based, resorbable composites for bone regeneration.

Hexagonal pore geometry and the presence of hydroxyapatite enhance deposition of mineralized bone matrix on additively manufactured polylactic acid scaffolds

“…9), which is in accordance with previous works [40,62]. AR staining and quantification of mineralization in our study indicated enhanced mineralization in the presence of HA, consistent with previous studies [26,38,65]. In this work, the presence of hexagonal pores of approximately 450 μm together with the presence of HA enhanced mineralization to a greater extent than when 200 μm triangular pores were used (Fig.…”

“…Similar studies using mineral reinforced 3D printed polymers consisting of PLA and bioglass have also reported a lack of significant improvement by the mineral incorporation in cell viability [62]. Babilotte et al reported a slightly increased adipocyte adhesion in the presence of 10% HA compared to pristine PLGA [26], although not statistically significant, similar to Orozco-Díaz et al describing slight improvements in the presence of 20% HA [38]. In our study, no improvement in cell viability was observed in the presence of HA, either present at surface level (PLAcHA) or embedded in the polymer matrix (PLA15HA; Fig.…”

“…Similarly, Orozco-Díaz et al reported higher calcium and collagen deposition on 3D-printed PLA dense scaffolds by osteoblast cell line MG-63 when 5 and 20% HA were present compared to pure PLA, although 10% wt. HA incorporation had a negative effect on the elastic modulus of the samples [38].…”

“…The most common ranges used for HA-PLA composites in FDM vary between 5 and 15% wt. [6,23,[26][27][28]38,39], although few studies have successfully incorporated larger amounts such as 25 [8], 30 [23,40] and 50% wt. [8,22], either by using twin-screw extruders or by reducing the particle size of the filler to the nanometric range and controlling the dispersion within the polymeric matrix.…”

The Relationship between Osteoinduction and Vascularization: Comparing the Ectopic Bone Formation of Five Different Calcium Phosphate Biomaterials

“…The reason has to do with the structure of the material and the animal species. Due to its material properties, HA has often been used in combination with other materials, osteogenic cells or osteogenic factors, such as collagen [ 25 ], polylactic acid (PLA) [ 26 ], sodium alginate (SA) [ 27 ], chitosan [ 28 ], graphene oxide [ 29 ], Zinc [ 30 ], BMSCs [ 31 ], bone morphogenetic protein-2 (BMP-2) [ 32 ], etc. Of course, HA has most commonly been used in conjunction with TCP, since TCP has better osteoinductive and degradation abilities [ 33 , 34 ].…”