Chitosan polymer as support to IgG immobilization for piezoelectric applications

Immunoenzymatic assays using gold plates and quartz crystal microbalance (QCM) analysis were carried out in order to evaluate chitosan/IgG interaction. Two chitosan solutions (S1 and S2) were prepared with different concentrations of NaOH (0.8% - S1 and 8% - S2). Absorbances 3-fold higher were obtained when chitosan (S2) was used as support when compared with direct IgG adsorption on gold. S1 on gold showed a better stability (at 22 degrees C, for 72 h) for IgG immobilization when compared with S2. However, S1 was used on QCM analysis and the IgG adsorption led to a non-Sauerbrey response, in which the mass on the electrode surface promote a proportional increase in the crystal resonant frequency. Direct IgG adsorption on gold electrode led to a 14.19% (+/- 2.43) increase in crystal frequency. When S1 was used as a support for IgG, a better immobilization occurred, causing a 24.34% (+/- 0.75) variation in crystal frequency. The structure of chitosan was shown to be efficient for IgG immobilization both in the immunoenzymatic method and in the QCM system. (C) 2013 Elsevier B.V. All rights reserved.