Influence of Preparative Carboxylation Steps on the Analyte Response of an Acoustic Biosensor

Biosensors typically work with analyte specific biomolecules coupled on a transducer surface. In many cases, biomolecule coupling requires intermediate carboxylation steps. We performed several experimental procedures for the carboxylation of an aminodextran (AMD) coated surface acoustic wave (SAW) biosensor prior to biomolecule coupling and investigated their impact on the analyte signal in a subsequent binding assay. The carboxylation procedures were based on glutaric anhydride (GA) solutions and molten GA, where molten GA led to lower analyte signals than GA solutions. This demonstrates that the mere experimental procedure to fulfill a certain immobilization strategy may play a critical role in the final performance of an acoustic biosensor.