Carbon nanotubes, Halloysite nanotubes and Gold nanoparticles: an overview of some applications for biomedical purposes

Abstract Today, nanotechnologies and nanomaterials are being used more widely, or will soon be used, in a variety of fields including health care. For nanomedicine, the three largest areas of application are diagnostics, drug delivery and regenerative medicine In this work we present some results concerning the use of different nanomaterials for medical purposes: Carbon nanotubes and Halloysite nanotubes Cancer growth and metastasis are strictly dependent on tumor angiogenesis, which is promoted by tumour cells upon secretion of a number of growth factors. Vessel formation is a complex multistep process during which 'activated' endothelial cells (ECs), the first mechanical and functional interface between blood and tissues, proliferate, migrate, differentiate and are stabilized in a new circulatory network. Being involved in nearly all of the ‘hallmarks of cancer’, there is an increasing consensus on the idea that ion channels play a significant role in driving cancer progression at all stages. Accumulating evidence tends to demonstrate that the development of some cancers could also involve such ion channel aberrations. In this context ion channels may be seen as potential novel therapeutic, diagnostic, and prognostic targets for anti-cancer therapies. The discovery of Transient Receptor Potential (TRP) superfamily of channels provided putative candidates for non-voltage-gated Ca2+ entry mechanisms. Notably, several TRP proteins are up regulated in cancer cells and have been suggested as valuable markers in predicting cancer progress and as potential targets for pharmaceutical therapy. In particular, the cold/menthol-sensitive TRPM8 (belonging to the ‘melastatin’ TRP subfamily) has emerged as an important factor in cell migration and prostate cancer (PCa) progression[1]. TRPM8 channel activation by menthol could be used to induce apoptosis of TRPM8-expressing prostate cancer cells and to inhibit angiogenesis. A great advancement in anti-angiogenic therapy has come from the use of nanotechnology since several nanovectors have been used as drug delivery systems (DDS) to efficiently target and kill tumor-associated vasculature. In this project we pursue a strategy of drug delivery using Halloysite nanotubes (HNTs) and functionalized to target tumor angiogenesis in PCa, conjugating these nanomaterials with a selective TRPM8 activator such as menthol. We evaluated the cytotoxic effect of functionalized HNTs on Human Endothelial Microvascular Cells (HMECs) trough cellular toxicity in vitro assay. HNTs were then functionalized with fluoresceine isotiocyanate (FITC) to study their cellular localization and finally we decided to non-covalently functionalize HNTs with menthol through vacuum cycles to selectively activate TRPM8 in HMECs [2]. Consequently, menthol-functionalized HNTs’ antiangiogenic role compared to free menthol was tested on HMEC through ECs migration and tubulogenesis in vitro assays. Menthol release was studied by GC-MS and the functionalized nanomaterials were characterized by TGA, SEM and TEM. Gold nanoparticles: Radiotherapy and Hadrontherapy are well known and widely used methods to treat cancer when surgery is not suitable or as a complement to a surgical intervention. Both approaches rely on the damage caused to cells by ionizing radiation, which is released mostly on cancer cells by means of IMRT techniques (Radiotherapy) or energy tuning (Hadrontherapy). The present work proposes an approach based on Au-nanoparticles bound to radiolabeled targeting agents and preliminary results will be presented.