AVS 52nd International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI-ThA

Paper BI-ThA1
Strategies to Increase the Sensitivity of Biosensors based on the Light Absorption of Immobilized Metal Nanostructures

Thursday, November 3, 2005, 2:00 pm, Room 311

Session: Bionanotechnology
Presenter: F. Frederix, IMEC, Belgium
Authors: F. Frederix, IMEC, Belgium
K. Bonroy, IMEC, Belgium
D. Saerens, VUB, Belgium
G. Maes, KULeuven, Belgium
S. Muyldermans, VUB, Belgium
G. Borghs, IMEC, Belgium
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The Transmission Plasmon Biosensor is a novel, cheap and easy-to-handle biosensing technique. It consists of immobilized metal nanoparticles that exhibit plasmon absorption peaks. This absorption is highly dependent on the size, the shape and the dielectric properties of the close environment of these nanoparticles and can therefore be used to perform biosensing. The nanoparticle films were realized using self-assembly techniques, thermal evaporation, electroless plating or soft-lithographic techniques. Mixed SAMs were used to couple antibodies to the nanoparticle films. The change in absorption properties of the nanoparticle films upon antibody-antigen binding was monitored in order to obtain quantitative information on the antibody-antigen interaction (prostate specific antigen). Besides the localised plasmon resonance sensing, we observed a novel physical phenomenon namely the intraband transition absorption enhanced sensing. Furthermore, the applied technique was identified to be a useful alternative for the most widely used clinical immunosensing technique, i.e. the ELISA technique. This promising alternative was applied onto modified microtitre plates, which allow for the implementation into an array technology. The Transmission Plasmon Biosensor fulfils therefore the needs of an ideal, multi-analyte bio(nano)sensor. However, the sensitivity could be a drawback of this sensing technique. We will show several strategies to increase the sensitivity to a diagnostically interesting concentration range (ng/mL range). These strategies will involve the use of camel antibodies to sense closer to the sensor surface (the sensitivity decreases exponentially away from the surface), the use of multiple nanoparticle films and nanoparticles with special morphologies. In addition, we will show that this sensing technique can be also applied for performing enzyme sensing and that it showed remarkable results for small molecule detection (antibiotics).