Characterisation and in vitro and in vivo evaluation of supercritical-CO2-foamed β-TCP/PLCL composites for bone applications

Abstract

Most synthetic bone grafts are either hard and brittle ceramics or paste-like materials that differ in applicability from the gold standard autologous bone graft, which restricts their widespread use. Therefore, the aim of the study was to develop an elastic, highly porous and biodegradable β-tricalciumphosphate/poly(Llactide-co-ε-caprolactone) (β-TCP/PLCL) composite for bone applications using supercritical CO 2 foaming. Ability to support osteogenic differentiation was tested in human adipose stem cell (hASC) culture for 21 d. Biocompatibility was evaluated for 24 weeks in a rabbit femur-defect model. Foamed composites had a high ceramic content (50 wt%) and porosity (65-67 %). After 50 % compression, in an aqueous environment at 37 °C, tested samples returned to 95 % of their original height. Hydrolytic degradation of β-TCP/PLCL composite, during the 24-week follow-up, was very similar to that of porous PLCL scaffold both in vitro and in vivo. Osteogenic differentiation of hASCs was demonstrated by alkaline phosphatase activity analysis, alizarin red staining, soluble collagen analysis, immunocytochemical staining and qRT-PCR. In vitro, hASCs formed a pronounced mineralised collagen matrix. A rabbit femur defect model confirmed biocompatibility of the composite. According to histological Masson-Goldner's trichrome staining and micro-computed tomography, β-TCP/PLCL composite did not elicit infection, formation of fibrous capsule or cysts. Finally, native bone tissue at 4 weeks was already able to grow on and in the β-TCP/PLCL composite. The elastic and highly porous β-TCP/PLCL composite is a promising bone substitute because it is osteoconductive and easy-to-use and mould intraoperatively.

Refractory Metal Coated Alumina Foams as Support Material for Stem Cell and Fibroblasts Cultivation

“…Pitkänen et al [ 25 ] worked out the contradicting results on the osteoinductive properties of β-TCP and were speculating that they might vary according to the surface properties of the material [ 26 , 27 ]. The brittle and hard calcium phosphates are very difficult to shape and implant.…”

“…Several groups reported that bone implants with a highly porous structure enhance immigration of (stem) cells [ 33 ] and the cellular induced deposition of minerals, a prerequisite of bone regeneration [ 25 ] and bone marrow niche homeostasis [ 17 ].…”

Preparation, physicochemical characterization, and in vitro and in vivo osteogenic evaluation of a bioresorbable, moldable, hydroxyapatite/poly(caprolactone‐co‐lactide) bone substitute

“…The monomer ratio of ε-caprolactone and lactide can be changed to alter the mechanical properties of the PCLLA copolymer, which can confer rubber-like elasticity. 22 In this study, a threearm macromolecule of PCLLA chains was polymerized via the copolymerization of ε-caprolactone and lactide. The process was initiated by hydroxyl groups of TMP.…”

Periodontal bone regeneration with a degradable thermoplastic HA/PLCL bone graft

“…24 Pihlman et al reported β-tricalcium phosphate and PLCL by supercritical CO 2 processing, which was further applied in a rabbit calvarial defect and showed good biocompatibility with improved angiogenesis and osteogenesis effect. 25,26 Akkouch et al designed a Coll/HA/PLCL scaffold, and the osteoblasts cultured on the composite displayed positive cell behavior and superior osteogenic phenotype. 27…”

“…24 Pihlman et al reported b-tricalcium phosphate and PLCL by supercritical CO 2 processing, which was further applied in a rabbit calvarial defect and showed good biocompatibility with improved angiogenesis and osteogenesis a State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral effect. 25,26 Akkouch et al designed a Coll/HA/PLCL scaffold, and the osteoblasts cultured on the composite displayed positive cell behavior and superior osteogenic phenotype. 27 Although PLCL showed great potential as a degradable carrier for bone grafts, it was challenging to achieve high content and homogenous dispersion of inorganic particles in the polymer during manufacturing.…”