Development of a piezoelectric immunosensor for the measurement of paclitaxel

This paper describes the development of a piezoelectric immunosensor for the measurement of paclitaxel (taxol), a natural anti-cancer agent. An antibody specific for taxanes was immobilized onto the surface of quartz crystals by means of the layer-by-layer self-assembly technique. The immobilization was achieved using electrostatic interactions between a precursor layer and the antibody molecules. The assembly process was monitored by a quartz crystal microbalance (QCM) and the topography of the modified quartz crystals was investigated by means of atomic force microscopy. The specific interaction of the immobilized antibody with paclitaxel in solution at different concentrations was monitored as a change in resonant frequency of the modified crystal. Moreover, the influence of non-specific adsorption was also characterized. The results show that the proposed immunosensor offers a promising alternative to classical analytical methods for a fast and easy determination of paclitaxel.