Temperature is a key parameter for the metabolism of cells. Indeed, there´s a narrow thermal range in which cells can live and grow. Temperatures slightly above this range (5 to 10 degrees more) start affecting their proteins and may cause irreversible damage if the exposure to the increased temperature is long (typically above one hour). For even higher temperatures, irreversible damage can be caused even for shorter heating times. These facts are behind hyperthermia treatments that seek killing infected cells by increasing temperature.
Nanotechnology brings the possibility of triggering this type of treatments in well located areas through minimally invasive techniques. Specifically, light can be used to excite physical processes in several materials that would subsequently provoke a thermal increase, constituting a technique known as photothermal therapy. A key example of such materials is given by plasmonic nanoparticles. When these nanoparticles are excited at the wavelength of the plasmon resonance, they can transform a large part of the absorbed energy into heat, creating a hot spot. Accordingly, placing them inside the infected area it is possible to apply localized photothermal treatments. However, due to the complexity of biological environments the actual control on the achieved temperature is low, as the actual light power reaching the particles as well as their exact number and distribution cannot be accurately described. From the therapeutic point of view this constitutes a major limitation, since it means that the achieved temperature in the infected spot can be too low to have any therapeutic effect, or too high, damaging the surrounding areas.
The starting idea of this project is to combine plasmonic nanoparticles that can transform light into heat with thermometric nanoparticles, whose luminescence can be used to deduce the temperature on the spot where they are. The nanoplatforms proposed here could then become therapeutic agents for several diseases, as long as the infected area is within the area accessible by light. In order to maximize this area, we proposed to create particles that would have their functionalities fully working in the near-infrared range of the electromagnetic spectrum, matching the regions where biological tissues have the lowest light extinction coefficients.
This project mainly faces the challenge of creating different materials with optimized functionalities, linking them together and then, testing them in biological environments. This requires stablishing links between chemistry, physics and biology, which is a valuable input for the development of nanomedicine, a research field that can potentially benefit society in a reasonable short term. The competitiveness that this field of research provides to Europe is supported by the large number of companies and consortia that work in it (e.g. Midatech, a British company devoted to the therapeutic use of gold nanoparticles; Madrid-MIT M+Vision, a Spanish/USA bioimaging research consortium or Nanobiotix, a French company working with oxide nanoparticles for cancer treatment). Indeed, the Global Nanomedicine Market is estimated to witness a compound annual growth rate of 14% during the forecast period 2017-2022, according to BCC Research.
