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This thesis concerned the development of patches for local target therapy and complete removal of cancer cells at polyp margins. It solves two complications that could occur after a polypectomy :
i)perforation: in case of flat or large tumor masses, the risk of perforation of the intestinal wall is so high that the resection cannot be carried out;
ii)residual cells: The entire removal of the tumor is not guaranteed, and occult residual malignant cells can remain on the tissue.
This work thesis concerned the design and fabrication of an ultrathin polymeric self-adhesive film, called “nanofilm”, and included the structural characterization, in vitro evaluation of biocompatibility of materials, and in vitro assessment of the thermal properties of the film. The fabrication of a multilayered nanofilm was based on[ poly-L-lactic]acid (PLLA), hydroxypropyl methylcellulose (HPMC) and 40 nm gold nanoparticles.
The thickness of the prototypes was measured by Atomic Force Microscopes (AFM) and they were also examined in terms of particles concentration and roughness by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The biocompatibility studies were performed with Trypan Blue and and calcein-ethidium staining of live and dead using human adenocarcinoma SW480 cells.
The thermoablation experiments for evaluating the ablative properties of the film embedding the nanoparticles were conducted with laser(532 nm) and extensive tests were performed using fluorescent microscopy to evaluate the viability of cells after laser stimulation. Finally the adhesion of the developed film was evaluated in an ex vivo experiment using freshly excised colon from pigs.
This work shows how a ultrathin adhesive film fabricated with multiple layers has stable adhesion, biocompatibility and thermo ablative properties.
Future work will be related to the optimization of the density of gold nanoparticles inside the polymeric film structure and the characterization of wetting properties of the nanometric layers in order to evaluate and control the contact between nanoparticles and cells. This final development phase will allow the optimization of the therapeutic properties of the film.