The stability of self-assembled monolayers with time and under biological conditions

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Maciel, J (Author) Other; Martins, MCL (Author) Other; Mário Adolfo Barbosa (Author) FEUP

Journal

Title: Journal of Biomedical Materials Research - Part A

Vol. 94A

Pages: 833-843

ISSN: 1549-3296

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 18 Citations

Scopus - 16 Citations

Other information

Authenticus ID: P-003-3HP

DOI: 10.1002/jbm.a.32746

Abstract (EN): The stability of self-assembled monolayers (SAMs) of different functionalities (CH(3)-, OH-, and EG4-) over time under appropriate storage conditions and when immersed in cell culture media was evaluated. X-ray photoelectron spectroscopy (XPS) was used to detect the oxidized sulfur species (S(2p) binding energy from 167 to 168 eV) resulting from oxidation of the surfaces. CH(3)-terminated SAMs stored for a period of 9 weeks in a nitrogen chamber were not altered. The same did not happen with OH- and EG4-SAMs, for which the XPS spectra evidenced oxidized peaks after 2 weeks. Regarding the stability of these surfaces under biological conditions, 30 min of immersion at 37 degrees C in serum-free or 10% fetal bovine serum (FBS) supplemented medium did not induce detectable oxidation. However, a small percentage of oxidized sulfur could have been washed out by the media, as confirmed in studies using SAMs immersed in water. Despite the possible rinsing out of oxidized thiols, high amounts of oxidation can still be detected by XPS. SAMs degradation during ethanol sterilization was not detectable by XPS, although a small increase on the wettability of OH-SAMs was observed. The data suggest that SAMs must be used freshly prepared, being recommended for short-term biological studies. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 94A: 833-843, 2010

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11