Classification of adsorbed protein static ToF‐SIMS spectra by principal component analysis and neural networks

Sanni, Oluwatoyin; Wagner, Mary B.; Briggs, D.; Castner, David G.; Vickerman, J. C.

doi:10.1002/sia.1438

Cited by 98 publications

(86 citation statements)

References 40 publications

(31 reference statements)

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“…Molecular organic fragments, such as CH 4 be characteristic residues of glycine, proline and hydroxyproline, the main amino acids of collagen [30,36]. We consider these signals also to be characteristics for the collagen matrix of the composite material bone.…”

Section: Discussionmentioning

confidence: 99%

Applicability of ToF-SIMS for monitoring compositional changes in bone in a long-term animal model

Henß

Rohnke

Khassawna

et al. 2013

J. R. Soc. Interface.

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Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a wellestablished technique in material sciences but has not yet been widely explored for implementation in life sciences. Here, we demonstrate the applicability and advantages of ToF-SIMS analysis for the study of minerals and biomolecules in osseous tissue. The locally resolved analysis of fragment ions deriving from the sample surface enables imaging and differentiation of bone tissue and facilitates histology on non-stained cross sections. In a rat model, bilateral ovariectomy combined with either a multi-deficiency diet or steroid treatment was carried out to create osteoporotic conditions. We focused our study on the Ca content of the mineralized tissue and monitored its decline. Calcium mass images of cross sections show the progressive degenerative changes in the bone. We observed a decreased Ca concentration in the edge region of the trabeculae and a decline in the Ca/P ratio. Additionally, we focused on the non-mineralized matrix and identified fragment ions that are characteristic for the collagen matrix. We observed trabeculae with wide ranges of nonmineralized collagen for the diet group owing to an impaired mineralization process. Here, the advantage of coeval monitoring of collagen and minerals indicated an osteomalacic model rather than an osteoporotic one.

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Section: Discussionmentioning

confidence: 99%

Applicability of ToF-SIMS for monitoring compositional changes in bone in a long-term animal model

Henß

Rohnke

Khassawna

et al. 2013

J. R. Soc. Interface.

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“…Sanni et al 167 employed ANN to differentiate between 13 different protein films, including two types of antibodies, using nominal mass values of all mass fragments available in the spectra. ANN was able to identify the key mass fragments associated with each of the proteins to employed ANNs to discriminate between an antibody and its proteolysis fragments adsorbed to silicon substrates, based solely on their ToF-SIMS spectra.…”

Section: Multivariate Analysismentioning

confidence: 99%

Orientation and characterization of immobilized antibodies for improved immunoassays (Review)

et al. 2017

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Orientation of surface immobilized capture proteins, such as antibodies, plays a critical role in the performance of immunoassays. The sensitivity of immunodiagnostic procedures is dependent on presentation of the antibody, with optimum performance requiring the antigen binding sites be directed toward the solution phase. This review describes the most recent methods for oriented antibody immobilization and the characterization techniques employed for investigation of the antibody state. The introduction describes the importance of oriented antibodies for maximizing biosensor capabilities. Methods for improving antibody binding are discussed, including surface modification and design (with sections on surface treatments, three-dimensional substrates, self-assembled monolayers, and molecular imprinting), covalent attachment (including targeting amine, carboxyl, thiol and carbohydrates, as well as “click” chemistries), and (bio)affinity techniques (with sections on material binding peptides, biotin-streptavidin interaction, DNA directed immobilization, Protein A and G, Fc binding peptides, aptamers, and metal affinity). Characterization techniques for investigating antibody orientation are discussed, including x-ray photoelectron spectroscopy, spectroscopic ellipsometry, dual polarization interferometry, neutron reflectometry, atomic force microscopy, and time-of-flight secondary-ion mass spectrometry. Future perspectives and recommendations are offered in conclusion.

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“…C x H y N þ fragments show up as well in the mass spectra although C x H y N þ type fragments are meant to be amino acid compounds from the organic part of the bone. 25 But due to the addition of several chemical compounds for the polymerization process like hardener (Tetramethylaniline, for example), accelerator [trisdimethyl(aminomethyl)phenol], or stabilizers, the presence of nitrogen containing fragments also deriving from the resin must be taken into account-for Epon as well as for Technovit.…”

Section: B Distinguish Fragments Of Embedding Materials and Bonementioning

confidence: 99%

Time of flight secondary ion mass spectrometry of bone—Impact of sample preparation and measurement conditions

Henß

Hild²,

Rohnke

et al. 2015

Biointerphases

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Time of flight secondary ion mass spectrometry (ToF-SIMS) enables the simultaneous detection of organic and inorganic ions and fragments with high mass and spatial resolution. Due to recent technical developments, ToF-SIMS has been increasingly applied in the life sciences where sample preparation plays an eminent role for the quality of the analytical results. This paper focusses on sample preparation of bone tissue and its impact on ToF-SIMS analysis. The analysis of bone is important for the understanding of bone diseases and the development of replacement materials and new drugs for the cure of diseased bone. The main purpose of this paper is to find out which preparation process is best suited for ToF-SIMS analysis of bone tissue in order to obtain reliable and reproducible analytical results. The influence of the embedding process on the different components of bone is evaluated using principal component analysis. It is shown that epoxy resin as well as methacrylate based plastics (Epon and Technovit) as embedding materials do not infiltrate the mineralized tissue and that cut sections are better suited for the ToF-SIMS analysis than ground sections. In case of ground samples, a resin layer is smeared over the sample surface due to the polishing step and overlap of peaks is found. Beside some signals of fatty acids in the negative ion mode, the analysis of native, not embedded samples does not provide any advantage. The influence of bismuth bombardment and O 2 flooding on the signal intensity of organic and inorganic fragments due to the variation of the ionization probability is additionally discussed. As C 60 sputtering has to be applied to remove the smeared resin layer, its effect especially on the organic fragments of the bone is analyzed and described herein.

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Classification of adsorbed protein static ToF‐SIMS spectra by principal component analysis and neural networks

Cited by 98 publications

References 40 publications

Applicability of ToF-SIMS for monitoring compositional changes in bone in a long-term animal model

Applicability of ToF-SIMS for monitoring compositional changes in bone in a long-term animal model

Orientation and characterization of immobilized antibodies for improved immunoassays (Review)

Time of flight secondary ion mass spectrometry of bone—Impact of sample preparation and measurement conditions

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