Optimization of Second Generation Photosensitizers by Vehiculization in Polyacrylamide Nanoparticles

GUALDESI, MARÍA S.; VARA J. ; ALVAREZ IGARZABAL C.I.; ORTIZ C.S.

Simposio; XIII ELAFOT; 2017

No corresponde

Polyacrylamide nanoparticles (PAA-NPs) are promising vehicles for the incorporation of drugs in photodynamic therapy (PDT) and photodynamic inactivation (PDI). The polymeric matrix of PAA-NPs protects the active form of the photosensitizer (PS) from possible enzymatic degradations or from the biological environment and prevents its aggregation. Thus, new NPs of different PAA, (2-hydroxyethyl methacrylate (HEMA-NPs) and (+) N,N´-Diallyl-L-Tartardianide (DAT-NPs), were synthesized to incorporated two second generation PS: monobrominated Neutral Red (NRBr) and monobrominated Azure B (AzBBr), with activity in PDT and PDI [1-2]. In this study, the PAA-NPs were prepared based on the inverse microemulsion polymerization. The obtained HEMA-NPs and DAT-NPs were characterized by size and zeta potential analysis with promising results. In addition, the oxidative activity was evaluated. Photooxidation of 9,10- Anthracenediyl-bis (methylene) dimalonic acid (ABDA) was also used to determine oxygen quantum yield (ΦΔ) by the photosensitizers. NRBr and AzBBr were used as references (ΦΔ= 1).According to the obtained results, it is possible to affirm that for the NRBr dye, the production of singlet oxygen increases considerably when this one is loaded in the nanoparticles, in comparison with it is free in water. Thus, for NRBr-HEMA-NPs, the value of ΦΔ was 3.5 times greater than that obtained for free NRBr. While NRBr-DAT-NPs, the value of ΦΔ tripled to the free PS. These results are very promising and would indicate that the PAA-NPs have the capacity to induce the reactive oxygen species generation of PS and lead to the formation of more singlet oxygen at the site.On the other hand, for the AzBBr, the observed behavior was similar to that for NRBr, the thiazine vehiculized dye, caused greater decomposition of ABDA than the free one. From the above, it can be deduced that the vehiculization of these dyes (NRBr and AzBBr) in the PAA-NPs is able to optimize the photochemical properties of the PS, which is an important advantage for the probable applications of these.