Photothermal technique applied to the characterization of nanoparticles incorporated into PPIX for application in the cancerous cells therapy

In this chapter are shown some applications of two photothermal techniques (Photoacoustic Spectroscopy, PAS, and Thermal Lens Spectrometry, TLS) to determine the characteristic non-radiative relaxation time (NRRT) and the thermal diffusivity. In addition, complementary techniques as Fluorescence Spectroscopy, Optical Absorption Spectrometry and TEM were used to determine the florescence intensity, the optical absorption and the particle sizes, respectively, of metallic solutions with gold nanoparticles (Au-np) and protoporphyrin IX (PpIX) for its applications in Photodynamic Therapy (PDT). This therapy is based on the preferential use of laser light and the presence of molecular oxygen in these cells. A thorough photothermal technique is possible to determine some physical parameters that help us to improve the PDT efficiency. Nowadays PDT is considered an effective method for diagnosis and treats some pre-malignant and malignant processes. PDT eliminates cancerous cells that accumulate the photosensitizer (Ps) which generate free radicals when this Ps is exposed to a laser beam with a suitable wavelength. The objective of this research is to improve the photothermal treatment with nanoparticles and PpIX incorporated in the cells using the PDT.