A Novel Piezoelectric Immunosensor for CA125 Using a Hydroxyapatite/Chitosan Nanocomposite-Based Biomolecular Immobilization Method

Abstract

The ideal immobilization methods that are suitable for binding immunoactive materials with high efficiency onto a sensing surface are the key target to pursue in current biosensor design. In the present paper, the formation of a hydroxyapatite/chitosan (HA/CS) hybrid nanocomposite is described and a general design strategy for immunosensing platforms is proposed on the basis of HA/CS nanocomposite and nanogold particle adsorption of antibodies. A quartz crystal microbalance used as a model transducer and the detection performances of the resulting immunosensor were investigated by using the immuno-system of CA125, an important indicator in the diagnosis of clinical cancers. The hybrid nanocomposite was characterized by scanning electron microscopy and transmission electron microscopy measurements. The frequency response characteristics for the processes of immobilization and immunoreaction of anchored anti-CA125 antibodies were studied in detail. It was found that the developed sensing interface has some advantages, such as activation-free immobilization and high antigen-binding activities of antibodies. The as-prepared immunosensor can allow the determination of CA125 in the concentration range 15.3–440.0 U mL–1. Such an interface design with the hybrid nanocomposite could be tailored as a new alternative used for biosensor design.