A comprehensive biological evaluation of ceramic nanoparticles as wear debris

Patients are exposed internally to nanoparticles (NPs) by wear mechanisms associated with total joint arthroplasty. This tissue-specific retention implies that the biological evaluation of NPs shall be integrative and niche targeting. Here, we report that ceramic zirconia and silicon nitride NPs interfere with MG63 cells' function and remarkably stimulate the secretion of TNF-alpha in RAW264.7 cells. However, alumina NPs significantly promote the alkaline phosphatase (ALP) activity of MG63 cells at low concentration and do not show irritation to macrophages. In this study, we prove that ceramic materials at nanoscale are bioactive to cells. These findings also suggest that a more rational paradigm for the biosafety evaluation of NPs than is currently in place is needed before their clinical applications. From the Clinical Editor: In this study, the authors demonstrate that ceramic nano materials associated with normal wear-and-tear of joint prostheses at nanoscale are bioactive to cells. (C) 2011 Elsevier Inc. All rights reserved.