Dr. Paul Wooley
Biological Responses to Nanoparticles – Does Size Really Matter?

Department of Orthopaedic Surgery

The biological response to particles, including those in the nano particle range, will be discussed in the context of nanotoxicology. There is considerable experience and literature from the orthopaedic field regarding adverse reactions to biomaterials in particulate form. Biomaterial debris, usually from the plastic component (ultra high molecular weight polyethylene; UHMWPE) generated from mechanical wear of prosthesis plays a critical role in aseptic loosening, the loss of implant support due to osteolysis in the surrounding bone. Recently, implant manufacturers have responded to this problem by introducing highly crosslinked UHMWPE (HX-UHMWPE) for prosthesis construction. It is well accepted that the wear rate of highly cross-linkedUHMWPE is lower than that of conventional polyethylene, but it appears that the wear debris particles are significantly smaller in size, with many sub-micron particles being generated from this new material. Since numerous factors (including size, charge and particle number) influence the biological responses to particles, we predict that the response to highly cross-linked UHMWPE will be different from conventional polyethylene. A battery of models used for the evaluation of biological response to particles will be described, including in vitro tests, animal models, and patient evaluations. These types of models should be considered as part of the safety testing for all forms of nanomedicine. Finally, the use of gene therapy to ameliorate the adverse response to particles will be described.

Biosketch

Location: Welcome Center at 2:30 p.m.