Design of PEI-conjugated bio-reducible polymer for efficient gene delivery

Abstract

The poly(cystaminebis(acrylamide)-diaminohexane) (poly(CBA-DAH)) was designed previously as a bio-reducible efficient gene delivery carrier. However, the high weight ratio required to form the polyplexes between poly(CBA-DAH) with pDNA is still a problem that needs to be addressed. To solve this problem and increase the transfection efficiency, poly(ethylenimine) (PEI, 1.8 kDa) was conjugated to poly(CBA-DAH) via disulfide bond. The PEI conjugated poly(CBA-DAH) (PCDP) can bind with pDNA at a very low weight ratio of 0.5 and above, like PEI 25 kDa, and form the polyplexes with nano-size (102-128 nm) and positive surface charge (27-34 mV). PCDP and PCDP polyplexes had negligible cytotoxicity and indicated similar or better cellular uptake than the comparison groups such as PEI 25 kDa and Lipofectamine® polyplexes. To confirm the transfection efficiency, the plasmid DNA (pDNA) encoded with the luciferase reporter gene (gWiz-Luc) and green fluorescent protein reporter gene (GFP) were used and treated with PCDP into the A549, Huh-7, and Mia PaCa-2 cells. PCDP/pDNA polyplexes showed highest transfection efficiency in all tested cell lines. In the luciferase assay, PCDP polyplexes showed 10.2 times higher gene transfection efficiency than Lipofectamine® polyplexes in mimic in vivo conditions (30% FBS, A549 cells). The VEGF siRNA expressing plasmid (pshVEGF), which is constructed as a therapeutic gene by our previous work, was delivered by PCDP into the cancer cells. The VEGF gene expression of PCDP/pshVEGF polyplexes was dramatically lower than control and the VEGF gene silencing efficiencies of PCDP/pshVEGF (w/w; 10/1) polyplexes were 54% (A549 cells), 77% (Huh-7 cells), and 66% (Mia PaCa-2 cells). In addition, PCDP/pshVEGF had reduced cell viability rates of about 31% (A549 cells), 39% (Huh-7 cells), and 42% (Mia PaCa-2 cells) and showed better results than all comparison groups. In the transfection efficiency and VEGF silencing assay, PCDP polyplexes showed better results than poly(CBA-DAH) at 4-fold lower weight ratio. The data of all experiments demonstrate that the synthesized PCDP could be used for efficient gene delivery and could be widely applied.

Recent advances in polymeric drug delivery systems

“…The PCDP polyplexes show 10 times higher gene transfection efficiency than Lipofectamine® polyplexes in bio-mimic in vivo condition. The bio-reducible PEI (1.8 kDa) conjugated poly (CBA-DAH) is finally concluded as an efficient polymeric gene delivery carrier [97,98]. It has been concluded that the PEI(1.8 kDa)-PCDP synthesized in our laboratory is one of the good candidates as mRNA, siRNA, and pDNA carriers for efficient gene delivery systems [99].…”

pH‐sensitive polymers: Classification and some fine potential applications

“…Transfection efficacy and cytotoxicity of PEI have been linked to its molecular weight, suggesting that branched PEI with higher molecular weight shows high transfection and cytotoxicity 216 . In order to address drawbacks such as cytotoxicity and possible particle aggregation leading to large particles and poor diffusion in the vascular system, core‐shell nanoparticles made of PEI and PMMA, 217 conjugated PEI, 218,219 dendritic polyglycerol dPG‐PEI nanogel platform, 220 or degradable PEIs with acid‐labile imine linkers and glutadialdehyde 216 were synthesized. Both approaches demonstrated the reduction of PEI's toxicity and their possible application to nonviral gene delivery.…”

Systemic administration of human mesenchymal stromal cells infected with polymer-coated oncolytic adenovirus induces efficient pancreatic tumor homing and infiltration

“…PEI-conjugated poly(CBA-DAH) [PCDP] was synthesized as described in a previous study [34,38]. The amine group of branched PEI (Mw; 1.8 kDa; Sigma, St. Louis, MO) was reacted with the activated NHS ester of succinimidyl 3-(2-pyridyldithio) propionate) (SPDP; Sigma), and the produced PEI-SPDP was dialyzed [dialysis membrane (MWCO = 1,000)] and lyophilized.…”

“…Others have similarly noted that polymer coating of Ad surface can expand Ad tropism and enhance its cellular internalization into different target tissues [30][31][32][33]. A bioreducible cationic polymer, a 1.8 kDa branched poly(ethylenimine) (PEI)-conjugated poly(cystaminebis(acrylamide)diaminohexane) (PCDP) [34] has been complexed with tumor extracellular matrix-degrading oAd expressing relaxin [35,36] via electrostatic interaction, generating oAd-PCDP complex. We investigated whether the PCDP can enhance virus internalization into hMSCs and evaluated tumor trafficking efficiency of oAd-PCDP-treated hMSC carriers, ultimately observing that oAd-PCDP-treated hMSCs elicits potent antitumor efficacy against pancreatic cancer by efficient viral replication.…”