Chitosan-graft-(PEI-β-cyclodextrin) copolymers and their supramolecular PEGylation for DNA and siRNA delivery.

Two water-soluble chitosan-graft-(polyethylenimine-β-cyclodextrin) (CPC) cationic copolymers were synthesized via reductive amination between oxidized chitosan (CTS) and low molecular weight polyethylenimine-modified β-cyclodextrin (β-CD-PEI). The two polycations, termed as CPC1 and CPC2, were characterized by proton nuclear magnetic resonance spectroscopy, gel permeation chromatography, and elemental analysis. These polycations exhibited good ability to condense both plasmid DNA (pDNA) and small interfering RNA (siRNA) into compact and spherical nanoparticles. Gene transfection activity of both polymers showed improved performance in comparison with native CTS in HEK293, L929, and COS7 cell lines. Further investigation of the gene transfection mediated by CPC2/DNA complexes showed both time-dependent and dose-dependent in the tested cell lines, where the polymer showed higher level luciferase expression than commercially available branched PEI (25 kDa) under the condition of high dose or extended time. Gene silencing activity mediated by CPC2/siRNA against luciferase expression showed superior knockdown effect in HEK293 and L929 cell lines. In addition, both polymers exhibited much lower cytotoxicity than PEI (25 kDa) in HEK293, L929, and COS7 cell lines. More interestingly, the pendent β-CD moieties of CPC copolymers allowed the supramolecular PEGylation though self-assembly of adamantyl-modified poly(ethylene glycol) with the β-CD moieties. The supramolecular PEGylation of the polyplexes significantly improved their stability under physiological conditions. The supramolecular PEGylated polyplexes of CPC with pDNA showed decreased transfection efficiency in all tested cell lines. However, remarkably, the supramolecular PEGylated polyplexes with siRNA exhibited even higher silencing efficiency in HEK293 and L929 cells (up to 84%), comparable to commercial DharmaFECT. The interesting mechanism for the enhanced silencing efficiency was discussed. With the pendent β-CD moieties on CTS chains, the system is expected to be further modified via inclusion complexation between β-CD unit and guest molecules to serve as a multifunctional delivery system.

Ping Y ，Liu C ，Zhang Z ，Liu KL ，Chen J ，Li J ... -  《-》

Low molecular weight linear polyethylenimine-b-poly(ethylene glycol)-b-polyethylenimine triblock copolymers: synthesis, characterization, and in vitro gene transfer properties.

Zhong Z ，Feijen J ，Lok MC ，Hennink WE ，Christensen LV ，Yockman JW ，Kim YH ，Kim SW ... -  《BIOMACROMOLECULES》

Cationic star polymers consisting of alpha-cyclodextrin core and oligoethylenimine arms as nonviral gene delivery vectors.

Yang C ，Li H ，Goh SH ，Li J ... -  《BIOMATERIALS》

Synthesis and characterization of polyrotaxanes consisting of cationic alpha-cyclodextrins threaded on poly[(ethylene oxide)-ran-(propylene oxide)] as gene carriers.

Yang C ，Wang X ，Li H ，Goh SH ，Li J ... -  《BIOMACROMOLECULES》

FGFR-targeted gene delivery mediated by supramolecular assembly between β-cyclodextrin-crosslinked PEI and redox-sensitive PEG.

A new redox-sensitive poly(ethylene glycol) (PEG)-based gene vector specially designed to target fibroblast growth factor receptors (FGFRs) was developed by host-guest supramolecular complexation. The new vector was designed as follows: 1) A host segment was consisted of β-cyclodextrin-crosslinked low molecular polyethylenimine (PEI) conjugated with MC11 peptide (MQLPLATGGGC) that can target FGFRs, being termed as MC11-PEI-β-cyclodextrin (MPC); 2) A guest segment is consisted of PEG and adamantyl group linked by a disulfide bond, the adamantyl-SS-PEG (Ad-SS-PEG); and 3) PEGylation of MPC by supramolecular complexation between MPC and Ad-SS-PEG to generate MPC/Ad-SS-PEG polycation, where the PEG chains can stabilize the DNA polyplexes extracellularly but can be readily cleavable intracellularly. It was found that the MPC/Ad-SS-PEG complexes could efficiently condense pDNA into nanoparticles around 100-200 nm, and were able to effectively stabilize polyplexes against salt- or BSA-induced aggregation. The MPC/Ad-SS-PEG polyplexes were more readily to dissociate with the aid of heparin in the presence of 5 mm DTT. In vitro gene transfection and cytotoxicity experiments in different carcinoma cell lines expressing FGFRs showed that MPC/Ad-SS-PEG could mediate significantly higher transfection efficiency than MPC complexed with adamantyl-PEG (MPC/Ad-PEG), which has no disulfide linkage and is non-PEG-detachable. Furthermore, confocal laser scanning microscopy study indicated that MPC/Ad-SS-PEG polyplexes could mediate much more efficient endosomal escape than stably shield MPC/Ad-PEG polyplexes at 12 h post-transfection. Importantly, MPC/Ad-SS-PEG was also able to efficiently mediate tumor-targeted gene delivery in the tumor-bearing mouse model after systemic injection in vivo. These results suggest that the MPC/Ad-SS-PEG systems could be a safe and efficient non-viral vector for FGFR-mediated targeted gene delivery for cancer gene therapy.

Ping Y ，Hu Q ，Tang G ，Li J ... -  《-》