Nanostructured thin films for the development of piezoelectric immunosensors.

Monoclonal antibodies were immobilized onto the surface of quartz crystals for the development of piezoelectric biosensors by means of the Layer by Layer self assembly technique (LBL). Specifically, the immobilization of immunoglobulins specific to the human cytokine Transforming Growth Factor Beta1 and to taxol was investigated. To this purpose multilayered ultra-thin films composed by precursor layers of cationic poly(dimethyldiallylammonium) chloride and anionic poly(styrenesulfonate) followed by a monolayer of antibodies were assembled by LBL. A quartz crystal microbalance was used to monitor and optimize the assembly process and to test the immunological activity of the deposited antibody molecules. Atomic force microscopy was used to characterize the surface roughness of the multilayers before and after the deposition of the immunoglobulins. The results confirmed the successful deposition of the proposed immunosensors and demonstrated their high potential for the measurement of analytes of clinical interest.