Photoacoustic Spectroscopy to determine in vitro the non radiative relaxation time of protoporphyrin IX solution containing gold metallic nanoparticles
CICATA-IPN, Legaria 694, Col. Irrigación, 11500 México, D.F., Mexico
2 Departamento de Física, CINVESTAV-IPN, AP 14-740, 07300 México, D.F., Mexico
3 Environment Citopathology Laboratory, Morphologia Departament, Escuela Nacional de Ciencias Biológicas del IPN, Carpio y Plan de Ayala S/N, Col. Sto. Tomas, CP 11340, México, D.F., Mexico
Corresponding author: email@example.com
In order to compare the non radiative relaxation time (NRRT) between standard protoporphyrin IX (PpIX) and protoporphyrin PpIX(1) solution containing gold metallic nanoparticles, we measured the photoacoustic spectroscopy (PAS) signal phase to determine, for each solution, the NRRT by using the Rosencwaig-Gesho theory, modified to include the effect of a finite non radiative deexcitation time. A NRRT average value, obtained for each solution, is reported and compared with some NRRT of triplet states reported in the literature for molecules with the same tetrapyrrolic structure. In the study was used PpIX disodium salt (DS) solution of 25% HCL. From each solution it was obtained its optical absorption spectrum, by using a UV-Vis spectrophotometer. After this, in the maximum observed optical absorption peak (404 nm), it was obtained the Photoacoustic (PA) signal phase as a function of the light modulation frequency, from 17 to 80 Hz. Our investigations are devoted to the improvement of the thermal treatments of drugs for medical applications.
© EDP Sciences, Springer-Verlag, 2008