Biomaterials SIMS analysis

Both XPS and TOF-SIMS are nowadays standard analytical tools for the determination of biomaterials surface chemistry. Examples of the use of XPS or TOF-SIMS for the analysis of biomimetic polymers include the investigation of different protein " ° and phosphate group modified polymeric surfaces. 

PCA had been employed to characterize the SIMS mass spectra of polymers and biomolecules [39,50]. PCA has also been applied to the interpretation of TOF-SIMS spectra of proteins and extended the application of TOF-SIMS measurement to biomaterials. The schematic of the procedure of PCA is shown in Figure 11.4. Prior to analysis, several peaks are selected from each spectrum. Normalization and pretreatment of the data are sometimes necessary to assure that the variance patterns highlighted are truly related to the chemical differencesbetweenthesamplesandnotmathematical differences in peak intensities. A typical data set X with m samples and n peaks then can be written as a matrix, with m rows and n columns. These are transformed into PCs by multiplication of the appropriate matrix. The... 

Fragment ions from biodevices are not always predictable because they contain complicated chemical additives in order to make them high in biocompatibility and performance. In addition, since some of the fragment ions from substrate materials generate protein-like complicated fragment ions, it is difficult to select appropriate peaks of fragment ions for data analysis of TOF-SIMS spectra. Therefore, an analysis technique which can be applied in all peaks in spectra is required. Information theory has been employed to help analyze TOF-SIMS data on biomaterials containing proteins to enable a selection of several important peaks from all peaks [55,100,101]. Mutual information, as defined by information theory, describes the specificity of every... 

Tyler, B., Ryal, G., Castner, D.G. (2007) Multivariate analysis strategies for processing ToF-SIMS images of biomaterials. Biomaterials, 28, 2412-2423. 

Sabbatini, L., Zambonin, RG. (1996) XRS and SIMS surface chemical analysis of some important classes of polymeric biomaterials. J. Electron. Spectrosc. Relat. Phenom., 81, 285-301. 

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