AVS 51st International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI-ThA

Paper BI-ThA3
Biosensing Based on Light Absorption of Immobilized Metal Nanostructures

Thursday, November 18, 2004, 2:40 pm, Room 210D

Session: Biosensors and Bio-Diagnostics
Presenter: F. Frederix, IMEC, Belgium
Authors: F. Frederix, IMEC, Belgium
K. Bonroy, IMEC, Belgium
G. Reekmans, IMEC, Belgium
C. Van Hoof, IMEC, Belgium
G. Maes, K.U.Leuven, Belgium
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The "Transmission Plasmon Biosensor" is a novel, cheap and easy to handle biosensing technique. Surface plasmon resonance sensors are widely used for biosensing. These sensors are highly sensitive to the refraction index at the interface between the metal film deposited upon a prism and a sample upon this metal surface. This principle can also be applied to a dielectric planar surface coated with nanostructures. The plasmon absorption peak position and intensity is highly dependent on the size of these particles and on the close proximity of these particles immobilized onto a surface. This research compromises the synthesis of metal nanoparticles with different sizes and morphologies, which were covalently immobilized on transparent substrates, e.g. glass, quartz and polymers using a molecular glue of silane layers. Particle films were also realized using various evaporation strategies, e.g. thermal evaporation, e-beam evaporation, sputtering and electroless plating. The different strategies were evaluated using TEM, AFM and absorption spectroscopy. The resulting plasmon resonance and interband absorption bands in the visible and UV region were compared. Mixed SAMs were used to couple antibodies to the metal nanoparticle films. The change in absorbance properties of the nanoparticle films upon antibody-antigen binding was monitored in order to obtain quantitative information on the antibody-antigen interaction. Besides the localised plasmon resonance sensing, we observed a novel physical phenomenon namely the interband 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 the implementation into an array technology. The Transmission Plasmon Biosensor fulfils therefore the needs of an ideal, multi-analyte bio(nano)sensor.