IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Biomaterials Monday Sessions
       Session BI-MoP

Paper BI-MoP10
Novel Immunosensor Interfaces Based on Mixed Self-assembled Monolayers of Thiols

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: Biorecognition Poster Session
Presenter: F. Frederix, IMEC, Belgium
Authors: F. Frederix, IMEC, Belgium
W. Laureyn, IMEC, Belgium
K. Bonroy, IMEC, Belgium
W. Dehaen, KULeuven, Belgium
G. Maes, KULeuven, Belgium
Correspondent: Click to Email
An ideal biosensor is characterized by its stability, reproducibility sensitivity and specificity towards a desired analyt. However, reduction of the size of the transducer and thus of the active area, requires an optimization of the sensing area. Our research is therefore also focussing on the biological recognition layer, which is based on an optimized covalent coupling of the antibodies to mixed self-assembled monolayers of thiols on gold. Since cleanliness and structural properties of the gold are of the utmost importance for perfect SAM formation, we have evaluated different cleaning procedures and induced the gold(111) structure. Characterization was performed with XRD and STM. The stability of the SAMs on gold with various properties was evaluated. To attach antibodies and/or avoid non-specific adsorption, novel thiols were synthesized. For standard covalent coupling procedures mercaptoethanol and ethanolamine are normally used as blocking molecules. We have synthesized blocking molecules based on ethylene oxide groups which show enhanced properties towards non-specific adsorption. The mixed monolayer formation was characterized using contact angle, cyclic voltammetry, impedance spectroscopy, XPS and GA-FTIR. The advantages of an orientated immobilization of chemically modified antibodies are demonstrated using SPR. We have evaluated the random amino and streptavidine-biotin coupling in comparison with the orientated aldehyde and thiol coupling procedures. Also the chemical modifications of these antibodies were optimized towards an increased sensitivity. Finally, we compared the sensitivity and selectivity with commercially available biological recognition layers, illustrating their enormous potential for further sensing applications.