Biocompatible Nanoparticles: Synthesis, Analysis and Applications in Biological and Medical fields

In recent years, technological development has allowed us to prepare, manipulate and characterize more nano-sized materials. Nanotechnology is an interdisciplinary field that involves the study and application of natural sciences and engineering to develop tools at the nanoscale. The nanotechnology applied to life sciences has led to improve knowledge about cellular and molecular processes and factors that cause a variety of diseases. The understanding of novel disease pathways has acted as a catalyst for the development of nanomedicine. Advances in this field promise to increase the accuracy and specificity of medical diagnoses and treatments of diseases. Metallic nanoparticles (NP), based on Ti, Au, Ag, Bi and others, embedded in an insulating medium behave like ionizing radiation absorbing centers, being able to show certain absorption resonances bands at specific wavelengths, thank to the Surface Plasmon Resonance (SPR) absorption effect. Their size distribution in a fluid changes the electronic and mass density and the material equivalent atomic number. The inclusion of metallic nanoparticles in a liquid, at different concentrations, modifies significantly the solution properties, especially in physical terms concerning the surface tension, density, viscosity, thermal and electric conduction, vapour pressure, and other parameters. The presented thesis work reports preliminary results on the use of metallic NPs for biomedical diagnosis and therapy in mice. In particular five aspects are discussed: (i) the preparation of different metallic nanoparticles by laser ablation in water; (ii) the characterization of their optical, morphological and structural properties by means of various spectroscopic techiniques; (iii) absorption calculations in water, soft tissues, and bones with and without the Au or Bi NPs solution of the typical biological diagnostics X-ray radiation energy (20 keV), using the absorption coefficients given by the NIST database; (iv) the improvement of contrast imaging produced by NPs in living mice, which takes place to a fast uptake and a slow decay in the mouse colon, as reported in Figs. 4.6 and 4.7; (v) the calculation of the Dose Ratio between the surface and the depth at which the tumor is located.