Development of poly(ethyleneimine) grafted amphiphilic copolymers: Evaluation of their cytotoxicity and ability to complex DNA

Abstract

Poly(ethyleneimine) (PEI) is one of the most widely used cationic polymers for gene delivery. The high molecular weight polymer, which is commercially available, is highly efficient but also very cytotoxic. The reduction in charge density by using nonlinear architectures based on low molecular weight (LMW) PEI is a promising approach to produce safer DNA-vectors. Herein, a group of cationic graft copolymers with different composition containing a hydrophobic biocompatible backbone and LMW linear PEI (lPEI) grafts obtained by ring opening polymerization and click chemistry was studied. The self-assembly and DNA complexation behavior of these materials was analyzed by the gel retardation assay, zeta potential measurements, and dynamic light scattering. The copolymers formed positively charged particles in water with average sizes between 270 and 377 nm. After they were added to DNA in serum-free medium, these particles acquired negative/near-neutral charges and increased in size depending on the N/P ratio. All copolymers showed reduced cytotoxicity compared to the 25 kDa lPEI used as reference, but the transfection efficiency was reduced. This result suggested that the cationic segments were too small to fully condense the DNA and promote cellular uptake, even with the use of several grafts and the introduction of hydrophobic domains. The trends found in this research showed that a higher degree of hydrophobicity and a higher grafting density can enhance the interaction between the copolymers and DNA. These trends could direct further structural modifications in the search for effective and safe vectors based on this polycation.

Synthesis of PEGylated amphiphilic block copolymers with pendant linoleic moieties by combining ring‐opening polymerization and click chemistry

“…According to previous reports, polymers obtained or modified through click chemistry often require long reaction times and large amounts of catalysts. [32,43,44] Thus, the resulting materials can be toxic and consequently present limitations for their use in biomedical applications. Herein, high conversion was observed at a low catalyst concentration, while the reaction time was shortened to 30 min.…”

Efficient in vitro and in vivo transfection of self-amplifying mRNA with linear poly(propylenimine) and poly(ethylenimine-propylenimine) random copolymers as non-viral carriers

“…52 This toxicity is most likely caused by the high overall positive charge of the L-PEI-based polyplexes, which can induce mitochondrial depolarization and subsequent necrotic cell death and apoptosis. 47,52,53 One approach to reduce cytotoxicity but maintain transfection efficiency is to chemically modify the PEI structures, 52 another one is to synthesize copolymers with lower charge density 54 or copolymers that resemble endogenous structures, e.g. polyamines.…”

Antheraea pernyi silk fibroin-coated adenovirus as a VEGF165-Ang-1 dual gene delivery vector

“…18,19 Despite the advantage of being noninfectious and less immunogenic, the disadvantage of nonviral vectors is low transfection efficiency. 20,21 On the other hand, viral vectors are natural delivery vectors with high infection efficiency and more viral promoters and enhancer elements, which can make the foreign genes encoded by the virus expressed at a high-level expression instantaneously. 22 Among them, adenovirus has been widely studied as a potential vector and showed high infection efficiency.…”