Reconstitutable charged polymeric (PLGA)2-b-PEI micelles for gene therapeutics delivery

Abstract

This study investigated the potential of creating a charged polymeric micelle-based nucleic acid delivery system that could easily be reconstituted by the addition of water. (PLGA 36kDa ) 2 -bbPEI 25kDa (PLGA MW 36kDa, bPEI M w 25kDa, PLGA:bPEI block ratio = 2) was synthesized and used to prepare cationic micelles. The copolymer retained proton-buffering capability from the bPEI block within the endosomal pH range. Micelle/pDNA complexes retained their particle size (100-150 nm) and surface charge (30-40 mV) following reconstitution. It was found that adding a small amount of low molecular weight bPEI (1.8 kDa) completely shielded pDNA in the micelle/pDNA complexes and enhanced transfection efficiency 50-100 fold for both fresh and reconstituted complexes without affecting complex size. Transfection efficiency for "reconstituted" micelle/pDNA/bPEI 1.8kDa (WR 1) complexes was 16-fold higher than its "fresh" counterpart. Although transfection levels achieved using "reconstituted" micelle/pDNA/ bPEI 1.8kDa complexes were 3.6-fold lower than control "fresh" bPEI 25kDa /pDNA (N/P 5) complexes, transfection levels were 39-fold higher than "reconstituted" bPEI 25kDa /pDNA (N/P 5) complexes. The micelle/pDNA/bPEI 1.8kDa system showed very low cytotoxicity in MCF7 cells even with pDNA doses up to 20 μg, and transfection levels increased linearly with increasing pDNA dose. These results indicate that this PLGA-b-bPEI polymeric micelle-based system is well suited as a reconstitutable gene delivery system, and has high potential for use as a delivery system for gene therapy applications.

Formulation of pH responsive peptides as inhalable dry powders for pulmonary delivery of nucleic acids

“…In this study, the particle size of DNA complexes of the reconstituted SD powders and SFD powders were larger than that of the freshly prepared complexes and it is possible that a higher proportion of DNA complexes of the reconstituted SD and SFD powders entered the cells through the more efficient caveolae-mediated endocytosis, thus achieving higher transfection efficiency. A similar phenomenon was observed by Mishra et al [53] who found that the reconstitution of lyophilised micelle/DNA/PEI complexes significantly enhanced the transfection efficiencies up to 16 times in MCF-7 cells compared to the freshly prepared counterparts and this was related to higher cellular uptake.…”

Advanced Engineering Approaches in the Development of PLGA-Based Nanomedicines

“…Amphiphilic derivatization of PLGA can be achieved by conjugation of hydrophilic polymer chains, such as, PEG [87,40,37] and poly(ethyleneimine) (PEI) [57]. The drug is loaded into the polymeric micelle via incorporation into the core [37], chemical conjugation to the block copolymer [87,40], or simple surface adsorption [57].…”

“…The drug is loaded into the polymeric micelle via incorporation into the core [37], chemical conjugation to the block copolymer [87,40], or simple surface adsorption [57]. PLGA-based polymeric micelles have shown promise in cancer therapy [87,40,37] and gene delivery [57].…”

Polymer-Drug Nanoconjugate – An Innovative Nanomedicine: Challenges and Recent Advancements in Rational Formulation Design for Effective Delivery of Poorly Soluble Drugs

“…An ideal polymeric micelle exhibits high drug loading capacity, biocompatibility, stability and controlled drug release however their CMC and other physicochemical properties are underpinned by the type and length of the hydrophilic and hydrophobic blocks. For instance greater hydrophobicity and longer hydrocarbon chain length of the block copolymer are associated with low CMCs (198)(199)(200). Most of the polymeric micelles invstigated did not contain any covalent bond between the drug and the micellar carrier hence may not be classified as polymer-drug conjugates.…”