GOLD NANOPARTICLES AGGREGATION EFFECT ON THE PHOTOACOUSTIC SPECTRA: THEORETICAL AND EXPERIMENTAL RESULTS.

Dublín

Simposio; 27th IUPAC International Symposium in Photochemistry; 2018

IUPAC

he different photophysical and photochemical properties of different nanosystems (NS) have allowed the development of nanomedicine as an effective tool in the detection and phototherapeutic treatment of diseases. Recently, studies have been developed regarding the use of NS for the therapeutic treatment of neoplastic diseases. This treatment is known as photothermal therapy, because is the relaxation of the excited state that generates a local increase in the temperature of NS. So the study of the photoacoustic (PA) and photothermal properties of different NS is fundamental for their understanding. Small nanoaggregates shows an enhancement of the electric field produced by the irradiation in the plasmon wavelenght. This field enhancement is localized in the gap zone between nanoparticles (NPs) and could lead to an increase in the photothermal effect. [1]In this work we analyse the shifts in the PA spectra during an aggregation process. The PA spectra of non aggregated NPs is similar to the extinction spectra as an indication that dispersion is negligible. However aggregated NPs presents a considerable diference between the extinction and PA spectra. In order to reinforce these studies we performed theoretical modelling of absorption contribution for the aggregates. For this we use TEM (Transmision Electronic Microscopy) images as an input of the population of the different aggregates presented at different times in the sample.The absorption spectra of the aggregation process of gold NPs was measure in spite of the interference of the dispersion.