AVS 52nd International Symposium
    Biomaterial Interfaces Friday Sessions
       Session BI+SS-FrM

Paper BI+SS-FrM4
Evaluation of Residues on Implant Surfaces by X-ray Photoelectron Spectroscopy

Friday, November 4, 2005, 9:20 am, Room 311

Session: Biomaterials Surface Characterization
Presenter: V. Frauchiger, Dr. H.C. Robert Mathys Foundation
Authors: V. Frauchiger, Dr. H.C. Robert Mathys Foundation
R. Luginbuehl, Dr. H.C. Robert Mathys Foundation
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Success of modern implants does not depend on the proper material choice only, but also on the surface chemistry and the proper removal of the ubiquitous present surface contaminations. There are many contemporary analytical methods that permit the qualitative and quantitative analysis of picogram amounts, but only a few methods are suitable for a direct assessment without a special preparation of the implants or the chemical extraction of residues. We applied X-ray photoelectron spectroscopy to assess the cleanliness of osteosynthesis plates and hip endoprosthesis implants. In addition, specially designed test coupon surfaces were used to simulate different surface textures. The samples were soiled with exact amounts of two model process adjuvants (MPA). The first one was based on a mixture of organic compounds used in lubricants and cutting fluids while the second one contained inorganic particles used in blasting processes. The cleaning efficacy of an industrial cleaning process in aqueous media and with sonication was tested. Imaging XPS was applied to localize critical contamination on the surfaces and small area analysis was used to identify the organic residues. In addition to XPS, GC-MS and gravimetric analysis were carried out as complementary techniques. Principal component analysis was used to establish a sensitivity at the ng/cm@super 2@ level by calculating the ratio between the bulk implant material and the carbon or other MPA specific elements. Cleaning tests revealed that the organic residues are completely removed upon proper choice of cleaning conditions and detergents. Residual inorganic particles were found on many samples with a blasted surface texture. The particles were removed only by special treatment of the samples.