liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
On the stability of carboxylic acid-terminated self-assembled monolayers: Influence of varying alkyl chain length
Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
Department of Functional Nanomaterials, Institute of Physics, Savanoriu 231, LT-02300 Vilnius, Lithuania.
Attana AB, Björnnäsvägen 21, SE-114 19 Stockholm, Sweden/Uppsala University, Ångström Laboratory, Solid State Electronics, P.O. Box 534, SE-751 21 Uppsala, Sweden.
Attana AB, Björnnäsvägen 21, SE-114 19 Stockholm, Sweden.
Show others and affiliations
(English)Manuscript (preprint) (Other academic)
Abstract [en]

The physio-chemical properties and storage stability of three carboxyl-terminated selfassembled monolayers (SAMs), prepared from ethanolic and acidified ethanolic thiolssolutions of HS-(CH2)nCONH-EG6CH2-COOH, n=3, 11 or 15 on gold, have been correlated to their performance as potential biosensor surfaces. The SAMs of the two longer thiols (n=11, 15) prepared from acidified thiol solutions displayed highly organized and crystallinelike alkyl and ethylene glycol portions. The length of the supporting alkyl chain also influenced the storage stability of the SAMs in nitrogen gas, water and acidified water/ethanol solutions. The two long alkyl chain SAMs exhibited excellent storage characteristics, whereas the short chain thiol resulted in a less storage stable SAM as revealed by increased molecular decomposition and desorption, and a significantly reduced biofunctionality.

National Category
Natural Sciences
URN: urn:nbn:se:liu:diva-19692OAI: diva2:227492
Available from: 2009-07-14 Created: 2009-07-14 Last updated: 2010-01-14Bibliographically approved
In thesis
1. Self Assembled Monolayers for Quartz Crystal Microbalance based Biosensing
Open this publication in new window or tab >>Self Assembled Monolayers for Quartz Crystal Microbalance based Biosensing
2009 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The work in this thesis has been focused on developing surfaces for use in biosensor systems, especially for quartz crystal microbalances. The surfaces were prepared by adsorption of organosulfur molecules onto gold substrates, so called self assembled monolayers (SAMs). By chemical synthesis these thiols can be specifically tailored to provide surfaces with desired properties. The investigated surfaces were all based on thiols terminated with carboxylic acid groups to render hydrophilic surfaces onto which desired proteins can be covalently attached.

In order to increase the performance of two dimensional carboxyl surfaces, a method for improving the immobilization of proteins to the surface was investigated. The immobilization levels of antibodies were increased by using N-hydroxysulfo-succinimide (sulfo-NHS), instead of N-hydroxy-succinimide (NHS), as stabilizer of the amine reactive intermediate formed by reaction of the carboxyl groups with 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). The negatively charged sulfo-NHS intermediate promotes the attraction of overall positively charged proteins and enables immobilization also at low pH. In addition, the orientation of the immobilized antibodies was shown to be dependent on the pI of the antibody and to have a profound effect on the subsequent interaction with the antigen.

The organization of carboxyl terminated SAMs can be poor due to the repellation between the polar terminal groups. By using acidified ethanol as solvent during the assembly step of monolayer formation, the organization in carboxyl terminated alkyl and oligo(ethylene glycol) SAMs was improved. However, the carboxyl groups were found to be converted to ethyl esters, the rate being related to the acid strength. Furthermore, the long-term stability of carboxyl oligo(ethylene glycol) SAMs was investigated. Here, the effect of alkyl chain length on the storage stability was of interest. A short alkyl chain was shown to have a profound negative effect on the storage stability of the SAM, resulting in decomposition and loss of functionality over time compared to when thiols with longer alkyl chains were studied.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2009. 31 p.
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1408
National Category
Natural Sciences
urn:nbn:se:liu:diva-19679 (URN)LiU-TEK-LIC-2009:16 (Local ID)987-91-7393-587-6 (ISBN)LiU-TEK-LIC-2009:16 (Archive number)LiU-TEK-LIC-2009:16 (OAI)
2009-08-17, Planck, Fysikhuset, Campus Valla, Linköpings Universitet, Linköping, 13:15 (English)
Available from: 2009-07-14 Created: 2009-07-10 Last updated: 2009-07-14Bibliographically approved

Open Access in DiVA

No full text

Other links

Link to Licentiate Thesis

Search in DiVA

By author/editor
Myrskog, AnnicaLiedberg, Bo
By organisation
Sensor Science and Molecular Physics The Institute of Technology
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 45 hits
ReferencesLink to record
Permanent link

Direct link