Determination of surface concentrations of individual molecule-layers used in nanoscale biosensors by in situ ATR-FTIR spectroscopy

Manuel Punzet, Dieter Baurecht, Franz Varga, Heidrun Karlic, Clemens Heitzinger

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

For the development of nanowire sensors for chemical and medical detection purposes, the optimal functionalization of the surface is a mandatory component. Quantitative ATR-FTIR spectroscopy was used in situ to investigate the step-by-step layer formation of typical functionalization protocols and to determine the respective molecule surface concentrations. BSA, anti-TNF-α and anti-PSA antibodies were bound via 3-(trimethoxy)butylsilyl aldehyde linkers to silicon-oxide surfaces in order to investigate surface functionalization of nanowires. Maximum determined surface concentrations were 7.17 × 10 -13 mol cm -2 for BSA, 1.7 × 10 -13 mol cm -2 for anti-TNF-α antibody, 6.1 × 10 -13 mol cm -2 for anti-PSA antibody, 3.88 × 10 -13 mol cm -2 for TNF-α and 7.0 × 10 -13 mol cm -2 for PSA. Furthermore we performed antibody-antigen binding experiments and determined the specific binding ratios. The maximum possible ratio of 2 was obtained at bulk concentrations of the antigen in the μg ml -1 range for TNF-α and PSA. © 2012 The Royal Society of Chemistry.
Original languageEnglish (US)
Pages (from-to)2431
JournalNanoscale
Volume4
Issue number7
DOIs
StatePublished - 2012
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUK-I1-007-43
Acknowledgements: We thank Prof. Wolfgang Lindner of the Chemical Faculty of the University of Vienna for his assistance in silane chemistry and the facilitation of the silanization protocol and Prof. Falkenhagen of the Danube University, Krems (Austria) for providing us with monoclonal hTNF-alpha antibody. This work has been financially supported by Austrian Science Fund (FWF) Project No. P20871-N31 and by Award No. KUK-I1-007-43, made by the King Abdullah University of Science and Technology (KAUST). We dedicate this article to the memory of Prof. Urs Peter Fringeli.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

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