Synthesis, characterization of calcium phosphates/polyurethane composites for weight‐bearing implants

Abstract

Calcium phosphate (CaP)/polymer composites have been studied as an alternative graft material for the treatment of bone defects. In this study, lysine-triisocyanate-based polyurethane (PUR) composites were synthesized from both hydroxyapatite (HA) and β-tricalcium phosphate (TCP) to reduce the brittleness of CaP and increase the bioactivity of the polymer. The mechanical properties and in vitro cellular response were investigated for both HA/PUR and TCP/PUR composites. The composites were implanted in femoral defects in rats, and in vivo bioactivity was evaluated by X-rays, micro-computed tomography (μCT), and histological sections. In biomechanical testing, PUR improved the mechanical properties of the CaP, thus rendering it potentially suitable for weight-bearing applications. In vitro cell culture studies showed that CaP/PUR composites are biocompatible, with β-TCP enhancing the cell viability and proliferation relative to HA. CaP/PUR composites also supported the differentiation of osteoblastic cells on the materials. When implanted in rat femoral defects, the CaP/PUR composites were biocompatible and osteoconductive with no adverse inflammatory response, as evidenced by X-rays, μCT images, and histological sections. Additionally, a histological examination showed evidence of cellular infiltration and appositional remodeling. These results suggest that CaP/PUR composites could be potentially useful biomaterials for weight-bearing orthopaedic implants.

Synthesis and characterization of novel elastomeric poly(D,L-lactide urethane) maleate composites for bone tissue engineering

“…Torsion and tensile properties, together with its observed ability to recover its original shape after deformation, evidence 4PLAUMA is elastomeric. The compressive moduli and strength of 4PLAUMA composites are similar to injectable two-component cements [49] and pressure-molded fillers [50] previously designed, or exceeding the properties of preceding materials [24, 51]. Our 4PLAUMA composites have a tension moduli comparable to the high-end of reported values for pressure-molded elastomeric composites [25, 26], show no significant difference with FRC torsional moduli [27].…”

Effects of particle size and porosity on in vivo remodeling of settable allograft bone/polymer composites

“…When implanted in femoral plug bone defects in rats [14, 16], rabbits [12, 17], or sheep [11], they generate a minimal and transient inflammatory response, support cellular infiltration and new bone formation, and degrade to non-cytotoxic compounds. Both low- and high-viscosity allograft/poly(ester urethane) BVFs have been shown to remodel by creeping substitution [12, 15, 17], in which osteoclasts infiltrate the material along the surface of the mineralized particles and osteoblasts subsequently deposit new mineralized matrix.…”

Advanced bioactive and biodegradable ceramic biomaterials

“…β -tricalcium phosphate is the dominant phase used for biomedical applications, typically used in a form of particles, porous 3-D structures, and frequently combined with other ceramic materials, such as calcium silicate (Fei et al , 2012), polymers, such as poly(trimethylene carbonate) (van Leeuwen et al , 2012), carboxymethyl-chitin (Taniyama et al , 2013), poly(lactic-co-glycolic acid) (Gala-García et al , 2012), poly-(D,L-lactide-glycolide) (Wang et al , 2013), poly(urethane) (Yoshii et al , 2012), chitosan (Tai et al , 2012) and proteins, such as collagen (Bian et al , 2012), recombinant human protein (Matsumoto et al , 2012), etc. Tricalcium phosphate in the β -phase is frequently paired with 8.4 One of the phase equilibrium diagrams proposed to describe the phase relationships in the CaO-P 2 O 5 system (Carrodeguas and De Aza, 2011;Kreidler and Hummel, 1967). hydroxyapatite in a biphasic structure, to attain materials with tunable resorption characteristics and enhanced tissue compatibility.…”