Development of a piezoelectric immunosensor for Paclitaxel measurement

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

Paclitaxel-containing nano-engineered polymeric capsules towards cancer therapy

Paclitaxel is one of the anticancer agents most often used in clinical oncology practice for the treatment of ovarian, breast and non-small cell lung cancers. Nanoengineered polymeric capsules (NPCs) represent a new and very effective tool for the encapsulation and smart release of different compounds. In present work capsules were fabricated by means of the layer-by-layer assembly of oppositely charged polyelectrolytes onto colloidal particles, followed by removal of the cores at low pH to obtain hollow microcapsules. Paclitaxel was loaded into the capsule. As tumors exhibit a lower extracellular pH than normal tissues, the property of NPCs to open the pores in their shell at slightly acidic pH values could be used for the triggered release of paclitaxel within a tumor microenvironment. For the characterization of NPCs, quartz crystal microbalance was used to monitor the process of shell growth on planar supports. The effective encapsulation of paclitaxel was then demonstrated by atomic force microscopy and micro-Raman spectroscopy, whereas its release was characterized by Uv-vis spectroscopy. Finally the biological activity of encapsulated paclitaxel against human breast cancer cells was assessed

Nanoengineered polymeric S-layers based capsules with targeting activity.

Nanostructured polymeric capsules are regarded as highly promising systems with different potential applications ranging from drug delivery, biosensing and artificial cells. To fully exploit this potential, it is required to produce bio-activated stable and biocompatible capsules. To this purpose, in present work we proposed the combination of the layer-by-layer self assembly method with bacterial S-layer technology to fabricate stable and biocompatible polymeric capsules having a well defined arrangement of functional groups allowing the covalent attachment of antibody molecules. Hollow microcapsules were obtained by the layer-by-layer self assembly of oppositely charged polyelectrolytes onto colloidal particles, followed by removal of the cores at acidic pH. S-layers were crystallized onto the shell of the obtained capsules. Quartz crystal microbalance was used to characterize the crystallization process onto planar surfaces. S-layer containing capsules were investigated by atomic force microscopy. Immunoenzymatic tests were performed to assess the effective modification of the S-layer with antibody molecules both on planar surfaces and on hollow capsules. Fluorescent microscopy was employed to visualize the presence of the antibody molecules onto the capsule shell and immunological tests used to assess the bioactivity of the immobilized antibodies. Finally, the in vitro cytotoxicity of fabricated S-layer containing capsules was studied. The obtained results demonstrated the possibility to fabricate bio-activated S-layer containing capsules with improved features in terms of biocompatibility