Serum resistant and enhanced transfection of plasmid DNA by PEG-stabilized polyplex nanoparticles of L-histidine substituted polyethyleneimine

Abstract

To improve transfection of plasmid DNA as well as serum protein stability of polyionic complex nanoparticles of branched polyethyleneimine (bPEI), poly(ethylene glycol) (PEG)-stabilized nanoparticles were made from L-histidine substituted bPEI (PEI-Histidine) synthesized by Fmoc chemistry. The polymer was characterized by TNBS assay, 1 H NMR, GFC, potentiometric titration and elemental analysis of carbon and nitrogen, DNA condensation, and the stability against extracellular matrix (heparin sulfate) was investigated by dye exclusion and agarose gel retardation assays. The nanoparticles were characterized by dynamic light scattering-zeta potential analyzer. Cytotoxicity and expression of enhanced green fluorescent protein (EGFP) were determined in hepatocellular carcinoma by MTT assay and fluorescent techniques. PEI-Histidine showed a reduced pK a without any significant loss of total primary amines. Plasmid DNA was condensed almost thoroughly with PEGylated polymers, either bPEI or PEI-Histidine, at lower critical N/P ratios. PEGylated PEI-Histidine showed the better resistance to heparin induced displacement and the lower cytotoxicity when it was compared to bPEI. Interestingly unlike bPEI, smaller and less positively charged nanoparticles were obtained from PEGylated PEI-Histidine at N/P ratio=2 that resulted in about 4 folds higher EGFP expression than bPEI without any significant cytotoxicity. These properties are consistent with the higher serum protein resistance and buffer capacity of PEGylated PEI-Histidine at endosomal acidic pH.

On Complex Coacervate Core Micelles: Structure-Function Perspectives

“…However, recent super-resolution optical microscopy studies reveal that oligonucleotide-based C3Ms remain intact after the endosomal escape, which suggests that it is the positively charged surface of the C3Ms at endosomal pH that destabilizes the membrane [ 63 ]. Some of the most efficient polycations include, PEI [ 64 , 65 ], poly(histidine) [ 66 ], dendrimers [ 19 ], and poly(aspartamide) [ 67 , 68 ]. Additional hydrophobic groups in the block copolymer, such as cholesterol, also facilitate endosomal escape as these promote interaction with the lipidic bilayer [ 13 ].…”

Polyionic complex of single-walled carbon nanotubes and PEG-grafted-hyperbranched polyethyleneimine (PEG-PEI-SWNT) for an improved doxorubicin loading and delivery: development and in vitro characterization

“…Despite widespread biological applications of PEI, they demonstrate some safety problems to different extents depending on their molecular weight, charge density, structure, and conformational flexibility (von Harpe et al 2000). Previous studies have shown that PEGylation of PEI could be significant in increasing their dispersion at high concentrations, minimizing aggregation of particulates, reducing interaction of polycation complexes with plasma protein components and erythrocyte aggregation, prolonged blood circulation and reduced systemic toxicity (Najafi et al 2015, Tang et al 2003. Therefore, we aimed to establish a new approach to disperse and stabilize SWNTs for drug delivery application by means of PEG-grafted hyperbranched polyethylenimine (PEG-g-PEI) as a hydrophilic biocompatible block copolymer.…”

Co‐condensation synthesis of well‐defined mesoporous silica nanoparticles: effect of surface chemical modification on plasmid DNA condensation and transfection

“…Interaction of the modified MSNs with pDNA results in retarding pDNA migration in gel electrophoresis [38]. This happens since the modified MSNs, unlike MCM-41-OH, bearing positive zeta potentials (Table 3) interacting with pDNA through electrostatic interactions to neutralise the negative charge of pDNA.…”

“…CHN Elemental Analyzer (Termo finningan, Germany) was used for determination of carbon (C), hydrogen (H), and nitrogen (N) content of the modified MSNs. Millimole N per gram of each sample was used for N/P calculations [38]. The samples' pores characteristics were examined through the determination of nitrogen adsorption at −196°C.…”