Synthesis and Characterization of a Novel Nanomicellar System Pluronic-PEI Suitable for Gene and Drug Co-Delivery in Cancer Therapy

Abstract

Polyethyleneimine (PEI) is a synthetic cationic polymer recognized as a non-viral gene carrier with high transfection efficiency. However, cytotoxicity issues limit its use. Pluronic block-copolymers conjugated with PEI have demonstrated promising results for multiparametric target gene/drug co-delivery in cancer with reduced side effects. The goal of this work was to synthesize and characterize a novel nanosystem Pluronic L121-PEI for gene/drug co-delivery. For this purpose, hydroxyl groups from Pluronic were activated using acryloyl chloride leading to the synthesis of a diacrylate intermediate, which was further conjugated with PEI. FTIR and 1H-NMR spectroscopy were used for structural characterization. Particle size, polydispersity index (PDI) and zeta potential were assessed by dynamic and electrophoretic light scattering, respectively. A fluorescent pyrene probe was used to evaluate the critical micellar concentration (CMC). A hemolysis experiment was performed to estimate the in vitro biocompatibility of the nanosystem. FTIR analysis showed that Pluronic diacrylate was successfully synthetized as a new band around 1730 cm−1 (C=O bond) appears. Its conjugation with PEI was confirmed by the presence of a band between 3380 and 3390 cm−1 (N–H bond). 1H-NMR results showed characteristic proton peaks from Pluronic (-CH3 at δ1.1 ppm) and from PEI (-CH2-CH2NH- between δ2.7–3.4 ppm) and the molar ratio Pluronic–PEI was 1:2. The nanoparticles’ hydrodynamic diameter was ca. 125 nm with a PDI below 0.250, and a charge nearby +30 mV. The CMC was around 50 μg/mL. The hemolysis ratio of a 5 mg/mL nanomicellar solution was less than 5%. A novel Pluronic L121-PEI was successfully synthesized, which was able to self-assemble in aqueous solution leading to the formation of biocompatible cationic polymeric micelles. Their small size is suitable for tumor-targeting and as they are positively charged they can be also valuable for gene delivery. Overall, this new nanosystem could be a promising multiparametric nanoapproach for gene/drug co-delivery in cancer therapy.