Mechanical properties and biocompatibility of poly(methyl methacrylate) bone cement containing microencapsulated tissue adhesive

One of the most broadly reported self-healing schemes is that pioneered by White and Sottos et al. in which a polymer matrix is co-embedded with a catalyst and microcapsules containing a reactive healing agent. Although this field has been steadily growing over the past 10 years, little discussion of extension into biomaterials has taken place and none of the existing systems employ materials acceptable for in vivo applications. Due to its long history of use, lack of postpolymerization modifications, and susceptibility to fatigue failure, poly(methyl methacrylate) (PMMA) bone cement is an attractive option for the first self-healing biomaterial designed utilizing the aforementioned embedded capsule and catalyst approach. Interfacial polymerization of a polyurethane prepolymer with 1,4-butanediol was performed to encapsulate 2-octyl cyanoacrylate (OCA), an FDA-approved tissue adhesive, using an oil-in-water emulsion. The compressive, tensile, and fracture toughness properties of commercial PMMA matrices containing various wt% of capsules were investigated. The proliferation and viability of MG63 human osteosarcoma cells following various exposure times to extracts from OCA, capsuleembedded bone cement, and bone cement without capsules were also examined. Incorporation of greater than 5 wt% capsules reduced the compressive and tensile strengths below commercially-accepted standards for bone cement. Fracture toughness, K, was increased by 13% with the inclusion of 3 wt% capsules but was decreased below the control value with contents of 15 wt% and higher. Additionally, cellular viability and proliferation were similar in cells exposed to media conditioned with commercial and capsule-embedded bone cements, suggesting the addition of capsules to the bone cement does not have a detrimental effect on the toxicity of the material