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

Paper BI-ThA9
Realization and Characterization of Porous Gold for Increased Protein Coverage for Biosensor Applications

Thursday, November 18, 2004, 4:40 pm, Room 210D

Session: Biosensors and Bio-Diagnostics
Presenter: K. Bonroy, IMEC, Belgium
Authors: K. Bonroy, IMEC, Belgium
J.-M. Friedt, IMEC, Belgium
F. Frederix, IMEC, Belgium
R. De Palma, IMEC, Belgium
M. Sàra, Center for NanoBiotechnology, Austria
B. Goddeeris, KULeuven, Belgium
G. Borghs, IMEC, Belgium
P. Declerck, KULeuven, Belgium
Correspondent: Click to Email
In recent years, there has been an increasing need for the detection of biochemical substances with low molecular weight. Biosensors could be an alternative to conventional analytical methods for monitoring these substances. However, generally applied biosensor systems are often not sensitive enough for direct detection of these compounds. Therefore, our research focuses on the development of biosensors with improved transducer capabilities and biological interfaces. We chose gold surfaces in combination with SAMs of thiols as platform for the immobilization of biomolecules because of its compatibility with existing biosensors. In previous research, the use of SAMs of thiols on flat gold surfaces showed several advantages concerning specificity and reproducibility for final biosensor applications. However, the main disadvantage of this approach is the 2D aspect of these layers compared to 3D surfaces (e.g. polymers). 3D surfaces, such as porous gold, would allow for the immobilization of a large number of molecules per surface area, facilitating higher biosensor responses. The presented research describes the analysis of the different parameters, which define the electrochemical growth of porous gold, starting from flat gold. QCM-D technique was used for online monitoring of the porous gold deposition. The resulting surfaces were characterized using SEM, cyclic voltammetry and contact angle measurements. Applied potentials of -0.5V were found to be the most adequate conditions to grow porous gold, resulting in a 16x increase in surface area. In addition, we evaluated the immobilization degree of S-layer and IgG proteins on these porous surfaces. The optimized deposition conditions for realizing porous gold substrates, lead to 3x increase of S-layer adsorption and 5x increase of anti-IgG recognition using QCM-D as biological transducer. We can conclude that the high specific area of the porous gold amplifies the final sensitivity of the original flat surface device.