Probing albumin adsorption onto calcium phosphates by x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry

Citation

Baio, J. E.; Weidner, T.; Interlandi, G.; Mendoza-Barrera, C.; Canavan, H. E.; Michel, R.; & Castner, D. G. (2011). Probing albumin adsorption onto calcium phosphates by x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. Journal of Vacuum Science & Technology B, 29(4).

Abstract

In this study the binding and assembly of bovine serum albumin (BSA) onto three different calcium phosphate phases (hydroxyapatite, dibasic calcium phosphate dihydrate, and beta-tricalcium phosphate) was investigated using a combination of x-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). XPS was used to record adsorption isotherms and to quantify the amount of BSA adsorbed onto the different CaP surfaces. On all three surfaces, a monolayer of adsorbed BSA was formed. ToF-SIMS was then used to investigate how the structure of BSA changes upon surface binding. ToF-SIMS data from BSA films on the three CaP surfaces showed intensity differences of secondary ions originating from both hydrophobic and hydrophilic amino acids. For a more quantitative examination of structural changes, the authors developed a ratio comparing the sum of intensities of secondary ions from hydrophobic and hydrophilic residues. A small, but statistically significant, increase in the value of this ratio (7%) was observed between a BSA film on hydroxyapatite versus dibasic calcium phosphate dihydrate. From this ratio, the authors can make some initial hypotheses about what specific changes in BSA structure relate to these differences observed in the ToF-SIMS data.(C) 2011 American Vacuum Society. [DOI: 10.1116/1.3613919]

Keyword(s)

adsorbed protein films
Adsorption
behavior
calcium compounds
conformational-changes
hydrophilicity
hydrophobicity
molecular biophysics
monolayers
organization
orientation
proteins
secondary ion mass spectra
self-assembled monolayers
serum-albumin
surface-chemistry
time of flight mass spectra
tof-sims
x-ray photoelectron spectra
xps

Notes

806YS
Times Cited:1
Cited References Count:57

Reference Type

Journal Article

Secondary Title

Journal of Vacuum Science & Technology B

Author(s)

Baio, J. E.
Weidner, T.
Interlandi, G.
Mendoza-Barrera, C.
Canavan, H. E.
Michel, R.
Castner, D. G.

Year Published

2011

Date Published

1309478400

Volume Number

29

Issue Number

4

ISSN/ISBN

1071-1023

DOI

Artn 04d113
Doi 10.1116/1.3613919