Self-Hardening Calcium Phosphate Cement-Mesh Composite: Reinforcement, Macropores, and Cell Response
Hockin D. Xu, Carl G. Simon Jr.
Calcium phosphate cement (CPC) self-hardens to form hydroxyapatite, has excellent osteoconductivity and bone-replacement ability, and is promising for dental, craniofacial and orthopedic repair. However, its low strength limits CPC to only non-stress repairs. This study aimed to reinforce CPC with meshes to increase strength, and to form macropores in CPC for bone ingrowth after mesh dissolution. A related aim was to evaluate the biocompatibility of the new CPC-mesh composite. Absorbable meshes were incorporated into CPC to provide strength and toughness, and then form interconnected cylindrical macropores suitable for vascular ingrowth. The composite strength, work-of-fracture and elastic modulus were measured in three-point flexure as a function of the number of mesh sheets in CPC ranging from 1 (a mesh on the tensile side of the specimen) up to 13 (mesh sheets throughout the entire specimen), and as a function of immersion time in a physiological solution from 1 d to 84 d.Cell culture was performed with osteoblast-like cells at 1 d and 14 d using fluorescence microscopy, and the cell viability was quantified using an enzymatic assay. The strength and work-of-fracture (mean SD; n = 6) of CPC containing 13 meshes were (24.5 7.8) MPa and (3.35 0.80) kJ/m2, respectively, significantly higher than (8.8 1.9) MPa and (0.021 0.006) kJ/m2 of CPC without mesh (Tukey's). Interconnected macropores were formed in CPC at 84 d immersion. The new CPC-mesh formulation supported the adhesion, spreading, proliferation and viability of osteoblast-like cells in vitro. In conclusion, absorbable meshes in CPC increased the strength by 3-fold and work-of-fracture by 150 times; interconnected macropores suitable for bone ingrowth were created in CPC after mesh dissolution. The higher strength may help extend the use of CPC to larger stress-bearing repairs, and the macropores may facilitate integration of CPC with adjacent bone.
and Simon, C.
Self-Hardening Calcium Phosphate Cement-Mesh Composite: Reinforcement, Macropores, and Cell Response, Journal of Biomedical Materials Research Part A, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852154
(Accessed December 4, 2023)