Biomedical Engineering Reference
In-Depth Information
Tissue
Material
Ion-beam
(a)
(b)
Placing the sample
on the grid
(c)
(d)
15.3
Schematic presentation of the FIB sample preparation for TEM
analysis using
in situ
lift-out. (a) Trenches are cut on either side
of the protected area of interest. (b) The lamella is attached to a
micromanipulator. (c) The lamella is transferred and attached to a
TEM grid. (d) Finally the sample is thinned until it reaches electron
transparency (~100 nm).
15.5 Examples of results
15.5.1 Arthroplasty
excessive wear of the articulating surfaces of joint implants leads to particulate
generation which may eventually cause implant loosening and clinical
failure in arthroplasties. For example, lausmaa and co-workers
37
studied
hip arthroplasties that had been retrieved owing to displacement, which in
turn was caused by excessive wear of the plastic acetabular lining. By using
different methods of materials analysis, it could be concluded that different
factors had contributed to the wear. Ft-iR-analysis of unused and retrieved
acetabular cups revealed a surface zone that was degraded by oxidation,
probably caused by the sterilization method used (gamma irradiation).
sem/eDX analysis of the worn plastic surfaces also showed the presence
of calcium phosphate particles embedded in the plastic. Apparently, this
material originated from the metallic backing of the acetabular component,
which was coated with plasma sprayed hydroxyapatite. Plasma sprayed
coatings are often associated with poor integrity, causing release of particles
