CpG loaded flourescent polymeric nanoparticles: a theranostic drug delivery system suitable for TLR based therapies

Designing nanoparticulate delivery systems suitable for simultaneous imaging have been attracting great interest. Several systems such as liposomes, micelles, dendrimers, nanospheres and nanocapsules are potential theranostic carriers in biomedical applications. Here, for the first time we describe a complexation strategy allowing us to deliver a TLR ligand along with simultaneous imaging of the tissues with fluorescent polymeric nanoparticles (NPs). METHOD: Four different NPs (P1, P2, P3 and P4) were used for biocompatibility and drug delivery experiments. RAW264.7 cells were incubated with NPs for indicated time periods and analyzed by FACS and confocal microscopy. Cytotoxicity experiments were performed with Dojindo reagent on RAW264.7 cells. In addition, cellular uptake of NPs in the presence of several scavenger receptor ligands was also investigated. Next, NPs were incubated with CpG ODN to yield nanocomplexes. In vitro and in vivo immunostimulatory effect of nanocomplexes was analyzed both on PBMCs or splenocytes. Pro-inflammatory cytokine production was assessed either by ELISA or in some cases by PCR.