Orthopedic grade Poly(methyl mathacrylate) (PMMA) has been in use for decades as a bone cement for prostheses anchoring. Bone cement, admixed with prophylactic antibiotics, typically gentamicin, tobramycin or vancamycin, is in widespread use in hip and knee replacement surgery. Problems exist with the current product, ranging from inadequate structural integrity to inefficient release of loaded antibiotics. This study has loaded clay nanotubes with gentamicin sulfate antibiotic and embedded the  nanotubes in the cement. The concept of a halloysite tubular nanocontainer for  sustained antibiotic release was investigated. Gentamicin loaded clay nanotubes (GLNs) admixed in PMMA bone cement provided slow, 10-100 hours release of gentamicin. GLNs did not admix with the implant bulk polymer and the bone cement composite tensile strength did not deteriorate even with as much as 10 wt % halloysite. Using TEM, SEM and SFM microscopy, GLNs were characterized as tubular nanoparticles of ca 50 nm external diameter, 15 nm lumenal diameter and 500-1500 nm in length. In a range of pH, it has a negative zeta-potential of ca -50 mV, allowing for good dispersibility in water-based polymers. HTNs may prove valuable for applications in dental implants and surgical prophylaxis. Our results show a maximum increase in Young's Modulus at 7.5% wt nanotube addition to cement. An adhesion test shows an increase of adhesion ability on cow bone when we increase the concentration of halloysite by weight. However, our results of flexural strength test shows a 10% decrease when 7.5% wt halloysite is added. Additionally, there is an exponential increase in antibiotic release with the addition of our nanotubes, some 10 times greater release than current cement compositions. Our results indicate that a 7.5% wt clay nanotube/PMMA composite outperforms the current PMMA cement that is commercially available.

Clay nanotube/poly(methyl methacrylate) bone cement composite with sustained antibiotic release

241st National Meeting (2011)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.