New poly(acrylamide) nanoparticles in the development of third generation photosensitizers

Abstract There are promising data on the use of poly(acrylamide) nanoparticles (PAA-NPs) in the development of third generation photosensitizers for application in antimicrobial photodynamic therapy. These nanoparticle delivery systems are suitable for biological applications and have potential for drug delivery due to their biocompatibility, chemical flexibility, easy preparation and low cost. The objective of this work was to obtain new PAA-NPs for the vehiculization of the monobrominated derivatives of Azure B (AzBBr) and Neutral Red (NRBr). These two dyes were found to have promising properties as photosensitizers. However, the use of nanotechnology was required to overcome difficulties in solubility, aggregation and stability in order to optimize their photodynamic efficiency. The combination of different monomers and crosslinkers allowed us to develop two new PAA-NPs. These systems were loaded with AzBBr and NRBr and characterized according to their morphology, size, polydispersity index and zeta potential. The new third generation photosensitizers showed better photochemical reactivity, chemical stability and photodynamic efficacy against Gram-positive and Gram-negative bacteria than the free photosensitizers. The use of this vehiculization strategy improved the properties of the second generation photosensitizers (AzBBr and NRBr) studied. This improvement in their properties makes them good candidates for potential phototherapeutic applications against numerous pathologies.