The use of targeted nanoparticles (NPs) as a platform for loading
photosensitizers enables selective accumulation of the
photosensitizers in the
tumor area, while maintaining their
photodynamic therapy (
PDT) effectiveness. Here two novel kinds of
methylene blue (MB)-conjugated
polyacrylamide (PAA) nanoparticles, MBI-PAA NPs and MBII-PAA NPs, based on two separate MB derivatives, are developed for
PDT. This covalent conjugation with the NPs (i) improves the loading of MB, (ii) prevents any leaching of MB from the NPs and (iii) protects the MB from the effects of
enzymes in the
biological environment. The loading of MB into these two kinds of NPs was controlled by the input amount, resulting in concentrations with optimal
singlet oxygen production. For each of the MB-NPs, the highest
singlet oxygen production was found for an MB loading of around 11 nmol mg(-1). After attachment of F3
peptide groups, for targeting, each of these NPs was taken up, selectively, by MDA-MB-435
tumor cells, in vitro.
PDT tests demonstrated that both kinds of targeted NPs resulted in effective
tumor cell kill, following illumination, while not causing dark toxicity.