Abstract

Process control methods for cell culture bioreactors include on-line monitoring of protein concentrations. Bioreactor samples typically contain high amounts of different proteins. The direct detection of a single protein in this complex medium is a challenging task within the development of biosensors with label-free detection. We introduce the development of a mass-sensitive biosensor based on surface acoustic waves (SAW) for the detection of hepatocyte growth factor/scatter factor (HGF/SF) in the serum containing medium of a miniaturized bioreactor for culturing hepatocytes. The specificity of the biosensor was obtained following two approaches. In the first approach, antibodies against HGF (anti-HGF) were immobilized covalently via an intermediate layer of dicarboxy polyethylene glycol on the biosensor surface. In the second approach, dextran sulfate and fucoidan were used as sensor coatings exploiting the fact that HGF binds specifically to those sulfated polysaccharides. Performing HGF assays, similar results were obtained using biosensors coated with dextran sulfate and biosensors coated with anti-HGF. Even higher sensor signals were obtained using biosensors coated with fucoidan, particularly at 37°C. Therefore, biosensor coatings based on biospecific sulfated polysaccharides offer a simple and cost-saving alternative compared to the commonly used coating with antibodies.

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