Layered double hydroxide induced advancement in joint prosthesis using bone cement: the effect of metal substitution† Govinda Kapusetti, a Raghvendra Raman Mishra, b Swati Srivastava, c Nira Misra, a Vakil Singh, d Partha Roy, c Santosh Kumar Singh, e Chanchal Chakraborty, f Sudip Malik f and Pralay Maiti * g Poly(methyl methacrylate) based bone cement and its nanocomposites with layered double hydroxide (LDH) have been developed with greater mechanical strength and biocompatibility as a grouting material for total joint arthroplasty. Bivalent magnesium has been replaced with trivalent aluminium with various mole ratios, keeping the layered pattern of the LDH intact, to cater for the effect of varying substitution on the property enhancement of the nanocomposites. The intercalation of polymer inside the LDH layers makes them disordered and mechanically stiffer and tougher by more than 100%. The thermal stability of bone cement has increased by more than 30  C in the presence of 1 wt% of nanoLDH, homogenously distributed in the bone cement matrix by creating an inorganic thermal barrier out of the LDH dispersion. The improvement in the properties of the nanocomposites has been explained in terms of the strong interaction between nanoLDH and polymer. The superior bioactivity and biocompatibility of the nanocomposites, as compared to pure bone cement, has been established through hemolysis assay, cell adhesion, MTT assay and cell proliferation using fluorescence imaging. The developed nanocomposites have been used as a grouting material and significant improvements have been achieved in fatigue behaviour with gradual increment of Al substitution in the Mg : Al mole ratio in nanoLDH, demonstrating the real use of the material in the biomedical area. In vivo experiments on rabbits clearly revealed the superior efficacy of bone cement nanocomposites, over pure bone cement and a blank. Introduction Poly(methyl methacrylate) (PMMA) based bone cement has been introduced as a grouting material for total joint replace- ment surgeries. 1 The space between the bone and implant can be lled with bone cement for stronger mechanical bonding to prevent destabilization during stress distribution between the bone–implant interface from everyday activities and the strength of the bone cement is somehow proportional to the joint's life/durability. 2 All commercial PMMA based bone cements are cold cured powder–liquid combined systems, and for clinical applications, powder and liquid components are combined and the mixture is inserted into bone where the polymerization reaction takes place. PMMA bone cement has the ability to resist fatigue related cracking to a certain extent. 3 The typical success rate of joint surgery is usually around 10– 20 years. More than 75% of failures are due to aseptic loosening which is attributed to impact induced failures in the cement mantle during cyclic loadings (fatigue) arising from poor mechanical properties of bone cement 4,5 and lack of bone adhesiveness (non-bioactivity). 6,7 Attempts are being made for new formulations of bone cement to improve fatigue strength to achieve better lifespans of the joint surgeries. Fracture tough- ness usually increases with increasing molecular weight of the polymers. 8,9 However, increase in viscosity makes it difficult to insert bone cement in to cancellous bone during implantation. In addition, it may inhibit the mechanical interlocking between bone and the implant. Reinforcement of bone cement by bres or particles might be an alternative technique to improve the a School of Biomedical Engineering, Indian Institute of Technology, Banaras Hindu University, Varanasi 221 005, India b Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221 005, India c Department of Biotechnology, Indian Institute of Technology Roorkee, 247667, Roorkee 247667, India d Department of Metallurgical Engineering, Indian Institute of Technology, Banaras Hindu University, Varanasi 221 005, India e Centre of Experimental Medicine and Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221 005, India f Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India g School of Materials Science and Technology, Indian Institute of Technology, Banaras Hindu University, Varanasi 221 005, India. E-mail: pmaiti.mst@itbhu.ac.in † Electronic supplementary information (ESI) available. See DOI: 10.1039/c3tb00004d Cite this: J. Mater. Chem. B, 2013, 1, 2275 Received 2nd January 2013 Accepted 28th February 2013 DOI: 10.1039/c3tb00004d www.rsc.org/MaterialsB This journal is ª The Royal Society of Chemistry 2013 J. Mater. Chem. B, 2013, 1, 2275–2288 | 2275 Journal of Materials Chemistry B PAPER Published on 28 February 2013. Downloaded by Banaras Hindu University on 12/06/2013 14:13:12. View Article Online View Journal | View Issue