Biomaterials, Particle and Ion Analysis
All of the materials that are used in prostheses and come in direct contact with living tissues must be thoroughly characterized for key mechanical properties, including wear resistance, and for the biocompatibility, including in bulk form and as particulates. The goal of the Biomaterials, Particles and Ion Analysis Laboratory (BPAL) of the Luck Research Center is to characterize the biofunctionality and bioactivity of the many types of materials used in orthopaedics, including polyers, metals and ceramics.
One of the main research lines in the BPAL is the evaluation of the degradation products of orthopaedic implants. During the past decade, researchers have become increasingly aware that, in addition to the amount of wear occurring with an implant, the size and shape of the wear particles (i.e., their morphology) are key factors that determine the nature and intensity of the reaction in the surrounding bone and tissues. The focus of the BPAL is to develop and apply reliable and efficient methods for recovering and characterizing the wear particles from the lubricants used in laboratory wear simulations, and from the joint fluids, periarticular tissues and bone obtained during revision of failed prosthetic joints. The type and concentration of metal ions also can be accurately measured, thus combining two powerful tools in the evaluation of implant degradation.
Specialized Research Techniques
The unique analytical techniques that were developed in the BPAL over the past several years provide a method for simultaneously recovering virtually all of the wear particles of several different types of materials. This new protocol has additional advantages, including minimizing contaminants and particle loss, and the ability to accurately quantify total amount of debris present in the sample. In 2011, a pair of manuscripts reporting the initial studies employing the new BPAL particle isolation protocol were honored with the John Charnley Award from The Hip Society.
Key Research Equipment
Beckman Optima XP80 ultracentrifuge, laminar flow cabinets, vacuum filtration system, tissue embedding system, optical microscopes, scanning electron microscope (FE-SEM Supra VP40, Zeiss), energy dispersive X-ray analysis (Noran Six System, Thermo), microtone (LKB 8800 Ultratome III), digital acquisition system (MVIA, CM-DIG-LT-C), image analysis software (Metamorph v. 6.3, Universal Imaging), atomic absorption spectroscopy (Varian, SpectraAA 220)
The Biomaterials, Particles and Ion Analysis Laboratory is under the direction of Fabrizio Billi, Ph.D., and includes Paul Benya, Ph.D., and Aaron Kavanaugh, B.S., laboratory manager.
- F. Billi, P. Benya, P. Campbell, E. Ebramzadeh, F. Chan, H. McKellop: Metal wear particles: what we know, what we don't know, and why. SAS Journal, 3, (4): 133-142; December 2009
- F.Billi; P. Campbell: Nanotoxicology of Metal Wear Particles in Total Joint Arthroplasty: A Review of Current Concepts. Journal of Applied Biomaterials and Biomechanics, 8: 1 - 6, 2010
- F. Billi: Wear Debris Isolation and Characterization, in Tribology and Bearing Surfaces in Total Joint Replacement, R. M. Streicher and A. Wang, Eds., 2011(ISBN: 978-81-7895-525-4
- F. Billi, P. Benya, A. Kavanaugh, E. Ebramzadeh, J. Adams, H. McKellop: The John Charnley Award Paper 2011, An accurate and extremely sensitive method to separate, display and characterize wear debris. Part 1: Polyethylene particles and Part II: Metal and Ceramic Particles, Clinical Orthopaedics and Related Research, in press.
The capabilities of the BPAL are available for industry-sponsored projects and collaborations with other academic institutions.
Please contact Fabrizio Billi, Ph.D., email FBilli@laoh.ucla.edu, or telephone (213) 742-1352.
Detailed information also is available at: www.orthopaedicparticleanalysis.com
Continue: Implant Retrieval Analysis
Preparing a sample for analysis of wear particles.
SEM micrograph of polythylene wear particles from an artificial hip
SEM micrograph of metal wear particles from an artificial hip
Drs. Billi and Benya examining the morphology of sub-micron sized wear particles.