AVS 52nd International Symposium
    Biomaterial Interfaces Monday Sessions
       Session BI-MoP

Paper BI-MoP39
Organosilane SAMs as a Platform to Tune the Immunosensor Performances

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Biomaterial Interfaces Poster Session
Presenter: R. De Palma, IMEC vzw, Belgium
Authors: R. De Palma, IMEC vzw, Belgium
S. Peeters, KULeuven, Belgium
K. Jans, IMEC vzw, Belgium
K. Bonroy, IMEC vzw, Belgium
S. Cappelle, Cytec Surface Specialities, Belgium
G. Reekmans, IMEC vzw, Belgium
W. Laureyn, IMEC vzw, Belgium
G. Borghs, IMEC vzw, Belgium
C. Van Hoof, IMEC vzw, Belgium
G. Maes, KULeuven, Belgium
Correspondent: Click to Email
A central requirement in the modification of immunosensor interfaces with biological receptors is to tether the biomolecule of interest covalently and in a well-controlled geometry. A key issue in the design of these sensors involves the development of a sensitive, specific, reproducible and tunable biological interface. Self-assembly of silanes is commonly used as an effective surface modification tool in micro-array applications. However, most silanes used for micro-array are optimized towards DNA applications. Using quartz crystal microbalance (QCM-D), we have shown that the use of these silanes for immunosensing leads to inadequate characteristics, i.e. low sensitivity and specificity. Here we report on the enhanced immunosensing performances of novel preactivated silane SAMs. These preactivated functions allow for the direct coupling of receptors, thereby increasing the amount of immobilized antibodies. Using these preactivated silanes, the antibody immobilization was found to be reproducible, straightforward and controllable and the activity of the immobilized receptors was retained. Due to the molecular architecture of these silanes, the sensitivity, detection limit and specificity increased significantly. The degree of non-specific adsorption could be tuned by using appropriate blocking agents. Furthermore, a synthesis route was developed to create PEG-modified preactivated silanes. Deposition of these silanes in mixed silane SAMs allows for the creation of tunable immunosensing platforms. The silane-based interfaces were also compared to the well-known system of mixed thiol SAMs. The molecular architecture of all deposited silane SAMs was studied using contact angle, XPS, cyclic voltammetry, AFM and RAIRS. A strong correlation was observed between the layer characteristics and their immunosensing properties. Our approach based on preactivated silane SAMs guarantees a tunable and versatile platform for surface engineering in biosensing and micro-arrays.