Thanks to recent advances in nanoscience and nanotechnology, inorganic nanoparticles, based on metal oxides or noble metals, can be prepared reproducibly with good control over chemical composition, shape, size distribution and the nature and density of surface functions. Knowing that, at this nanometric scale, these compounds have both remarkable physical properties (e.g. superparamagnetism for ferro- or ferrimagnetic compounds ; surface plasmon resonance for metals) and are small enough to circulate in the blood and penetrate the various cellular compartments, they now have a real card to play in the development of injectable devices, particularly for the safe, controlled delivery of active ingredients.
After a brief overview of the specifications for a drug delivery device (DDD), we'll see that mesoporous silica nanoparticles obtained by sol-gel process can host molecules of therapeutic interest and thus serve as containers to transport these molecules to their target. We'll also see that iron oxide nanoparticles are very good contrast agents for medical magnetic resonance imaging (MRI) and that, when inserted into a DDM, they can be used to monitor its biodistribution after intravenous injection, and thus determine the moment when it reached its target. These same magnetic nanoparticles also have the ability to heat up inductively, i.e. when subjected to an alternating magnetic field. This property has led to the development of a new therapeutic strategy in oncology called magnetic fluid hyperthermia, which exploits the fact that tumor cells are more sensitive to a rise in temperature than healthy cells. Inserted into a MDD, they could remotely trigger the release of active ingredients. Using the same principle, gold nano-rods heat up when they absorb near-IR radiation. As living tissue is relatively transparent in this wavelength range, a technology based on a laser and DDMs incorporating gold nano-rods is currently under development.
Although multidisciplinary, this presentation will focus on the design of materials and the exploitation of their physical properties. It will therefore be largely incomplete on biological, galenical and medical aspects.
