Polyacrylamide nanoparticles(PAA-NPs) are promising vehicles for the incorporation of drugs in photodynamictherapy (PDT) and photodynamic inactivation (PDI). The polymeric matrix ofPAA-NPs protects the active form of the photosensitizer (PS) from possibleenzymatic degradations or from the biological environment and prevents itsaggregation. Thus, new NPs of different PAA, (2-hydroxyethyl methacrylate(HEMA-NPs) and (+) N,N´-Diallyl-L-Tartardianide (DAT-NPs), were synthesized toincorporated two second generation PS: monobrominated Neutral Red (NRBr) andmonobrominated Azure B (AzBBr), with activity in PDT and PDI [1-2]. In thisstudy, the PAA-NPs were prepared based on the inverse microemulsion polymerization.The obtained HEMA-NPs and DAT-NPs were characterized by size and zeta potentialanalysis with promising results. In addition, the oxidativeactivity was evaluated. Photooxidation of 9,10- Anthracenediyl-bis (methylene)dimalonic acid (ABDA) was also used to determine oxygen quantum yield (Φ_Δ) by the photosensitizers.NRBr and AzBBr were used as references (Φ_Δ=1).

According to the obtainedresults, it is possible to affirm that for the NRBr dye, the production ofsinglet 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 Φ_Δ was 3.5 times greater than thatobtained for free NRBr. While NRBr-DAT-NPs, the value of Φ_Δ tripled to the free PS. These results arevery promising and would indicate that the PAA-NPs have the capacity to inducethe reactive oxygen species generation of PS and lead to the formation of moresinglet oxygen at the site.

On the other hand, forthe AzBBr, the observed behavior was similar to that for NRBr, the thiazinevehiculized dye, caused greater decomposition of ABDA than the free one. Fromthe above, it can be deduced that the vehiculization of these dyes (NRBr andAzBBr) 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.