Cross-linked Low Molecular Weight Research Articles

Synthesis and Coordination Properties of a Water-Soluble Material by Cross-Linking Low Molecular Weight Polyethyleneimine with Armed Cyclotriveratrilene.

In this study, a full organic and water-soluble material was synthesized by coupling low molecular weight polyethylenimine (PEI-800) with cyclotriveratrilene (CTV). The water-soluble cross-linked polymer contains hydrophobic holes with a high coordination capability towards different organic drug molecules. The coordinating capability towards hydrophilic drugs (doxorubicin, gatifloxacin and sinomenine) and hydrophobic drugs (camptothecin and celastrol) was analyzed in an aqueous medium by using NMR, UV-Vis and emission spectroscopies. The coordination of drug molecules with the armed CTV unit through hydrophobic interactions was observed. In particular, celastrol exhibited more ionic interactions with the PEI moiety of the hosting system. In the case of doxorubicin, the host–guest detachment was induced by the addition of ammonium chloride, suggesting that the intracellular environment can facilitate the release of the drug molecules.

A Co-Delivery System of Curcumin and p53 for Enhancing the Sensitivity of Drug-Resistant Ovarian Cancer Cells to Cisplatin.

In order to enhance the sensitivity of drug-resistant ovarian cancer cells to cisplatin (DDP), a co-delivery system was designed for simultaneous delivery of curcumin (CUR) and p53 DNA. Firstly, the bifunctional peptide K14 composed of tumor targeting peptide (tLyP-1) and nuclear localization signal (NLS) was synthesized. A nonviral carrier (PEI-K14) was synthesized by cross-linking low molecular weight polyethyleneimine (PEI) with K14. Then, CUR was coupled to PEI-K14 by matrix metalloproteinase 9 (MMP9)-cleavable peptide to prepare CUR-PEI-K14. A co-delivery system, named CUR-PEI-K14/p53, was obtained by CUR-PEI-K14 and p53 self-assembly. Furthermore, the physicochemical properties and gene transfection efficiency were evaluated. Finally, ovarian cancer cisplatin-resistant (SKOV3-DDP) cells were selected to evaluate the effect of CUR-PEI-K14/p53 on enhancing the sensitivity of drug-resistant cells to DDP. The CUR-PEI-K14/DNA complexes appeared uniformly dispersed and spherical. The particle size was around 20–150 nm and the zeta potential was around 18–37 mV. It had good stability, high transfection efficiency, and low cytotoxicity. CUR-PEI-K14/p53 could significantly increase the sensitivity of SKOV3-DDP cells to DDP, and this effect was better as combined with DDP. The sensitizing effect might be related to the upregulation of p53 messenger RNA (mRNA), the downregulation of P-glycoprotein (P-gp) mRNA, and the upregulation of BCL2-Associated X (bax) mRNA. CUR-PEI-K14/p53 can be used as an effective strategy to enhance the sensitivity of drug-resistant ovarian cancer cells to DDP.

Reactive Oxygen Species (ROS)-Degradable Polymeric Nanoplatform for Hypoxia-Targeted Gene Delivery: Unpacking DNA and Reducing Toxicity.

Smart polymers as ideal gene carriers have drawn increasing attentions due to the effective DNA release once triggered by intrinsic stimuli, as well as reduced cytotoxicity. Herein, a stimulus-responsive, positively charged and water-soluble polymer (OEI-TK x) was facilely engineered by cross-linking low molecular weight oligoethylenimine (OEI) via thioketal (TK) linkages that would cleave selectively in reactive oxygen species (ROS)-rich environments induced by hypoxia. Agarose gel electrophoresis assay demonstrated that the threshold N/P ratios for complete retardation of negatively charged DNA migration were above 5 for OEI-TK x. The reduction in DNA-condensing capability and the changes in particle size, size distribution and particle morphology all illustrated that OEI-TK x possessed excellent ROS responsiveness. OEI-TK x/DNA polyplexes showed lower toxicity and higher gene transfection efficiency compared with PEI/DNA polyplexes. Theoptimum formulation, OEI-TK x/DNA polyplexes (N/P = 40), showed a little better performance than PEI/DNA polyplexes in cellular uptake profile. Furthermore, OEI-TK x/DNA polyplexes could escape from endosomes to the cytosol as efficiently as PEI/DNA polyplexes. Confocal images confirmed that OEI-TK x/DNA polyplexes could more effectively release DNA than PEI/DNA polyplexes, mainly owing to the valid cleavage of thioketal linkages induced by characteristic rich-ROS in Hela cells. These results suggested that OEI-TK x could represent an on-demand stimulus-responsive gene delivery platform.

Addition of free poloxamer 407 to a new gene vector P407-PEI-K12 solution forms a sustained-release in situ hypergel that enhances cell transfection and extends gene expression.

To address the concern around the efficiency/cytotoxicity ratio and the tumor-targeting effects of polyethylenimine (PEI), is a non-viral gene vector used for the delivery of the cancer therapy gene, poloxamer 407 (P407)-PEI-K12, was synthesized by cross-linking low-molecular weight PEI with P407 and further coupling a bifunctional peptide, K12, which is comprised of the tumor-targeting peptide tLyP-1 and the nuclear localization sequence. Furthermore, the addition of free P407 into the polymer/DNA complex solution produced a temperature-sensitive in situ gel-P407/P407-PEI-K12/DNA complex, which improved the effects of sustained-release gene delivery and transfection efficiency. The specificity, cytotoxicity and gene transfection efficiency of P407-PEI-K12 was investigated in Hela cells in vitro. The polymer efficiently prevented the degradation of plasmid DNA by DNase I and had a marked ability for serum tolerance. Agarose gel electrophoresis revealed that plasmid DNA was efficiently condensed and protected. The higher transfection efficiency of P407-PEI-K12h (the molar ratio of P407-PEI and K12 is 1:10) was achieved with a polymer and plasmid DNA ratio (w/w) of 20:1. The ability of free P407 to promote the transfection of the polymer/DNA complex was high (0.09%). The half-life of the P407/P407-PEI-K12-h/DNA gel complex was 228 min, and the transfection efficiency of the P407/P407-PEI-K12-h/DNA complex was markedly higher compared to that of the P407-PEI-K12-h/DNA complex at various release times.

PH-Responsive Cross-Linked Low Molecular Weight Polyethylenimine as an Efficient Gene Vector for Delivery of Plasmid DNA Encoding Anti-VEGF-shRNA for Tumor Treatment.

RNA interference (RNAi) is a biological process through which gene expression can be inhibited by RNA molecules with high selectivity and specificity, providing a promising tool for tumor treatment. Two types of molecules are often applied to inactivate target gene expression: synthetic double stranded small interfering RNA (siRNA) and plasmid DNA encoding short hairpin RNA (shRNA). Vectors with high transfection efficiency and low toxicity are essential for the delivery of siRNA and shRNA. In this study, TDAPEI, the synthetic derivative of low-molecular-weight polyethylenimine (PEI), was cross-linked with imine bonds by the conjugation of branched PEI (1.8 kDa) and 2,5-thiophenedicarboxaldehyde (TDA). This biodegradable cationic polymer was utilized as the vector for the delivery of plasmid DNA expressing anti-VEGF-shRNA. Compared to PEI (25 kDa), TDAPEI had a better performance since experimental results suggest its higher transfection efficiency as well as lower toxicity both in cell and animal studies. TDAPEI did not stimulate innate immune response, which is a significant factor that should be considered in vector design for gene delivery. All the results suggested that TDAPEI delivering anti-VEGF-shRNA may provide a promising method for tumor treatment.

Preparation, Characterization and Thermodynamics of Cross-linked Low Molecular Weight Chitosan Pyruvic Acid Derivatives

Preparation, Characterization and Thermodynamics of Cross-linked Low Molecular Weight Chitosan Pyruvic Acid Derivatives

Polymeric Vectors for Strategic Delivery of Nucleic Acids

Genomic modification through nucleic acid delivery is a frequently applied method in fundamental biological studies and offers a potent therapeutic strategy for disease treatment and biological research. Delivery of nucleic sequences is therefore an attractive facet of biological nanotechnology as highly specific, efficient, and nonantagonistic delivery is necessary for in vivo and clinical use. Previous vectors have suffered from immunogenic responses, serum dependent inactivation, and cytotoxicity, hindering their translational applicability. Current research in polymeric-based nucleotide delivery strives to offer a highly biocompatible, broad use vector through the utilization of polypeptide and polyamine conjugation that can be easily tailored for specific targeting or wide dissemination. Cross-linking low molecular weight polyamines and lipophilic derivatization for amphiphile creation has lead to improved biocompatibility and transfection efficiency compared to higher molecular weight polyamines. Derivatization of hyperbranched and dendritic polyamido- and polyamines has allowed for the formation of efficient in vivo transfection vectors; ring opening synthesis of N-carboxyanhydride amino acids have led to controlled peptide architectures for improved transfection while simultaneously providing convenient primary amines useful in functionalization. Polymer libraries of poly(ß-amino esters) have provided insights into useful architectures for in vitro and in vivo gene delivery. Grafting small molecules to polyamines, such as folate and galactose, for enhanced interaction with cell surface receptors for selective targeting of specific cell types has proven to be encouraging and remains a prominent aspect in biological nanotechnology.

Alkyl cross-linked low molecular weight polypropyleneimine dendrimers as efficient gene delivery vectors.

In recent years, polypropyleneimine (PPI) dendrimers have attracted great interest as non-viral gene delivery systems because of their attractive features including highly branched architecture with number of reactive end groups. However, without being structurally modified, they are not efficient gene carriers. In the present study, generation 2 and 3 (G2 and G3) of PPI dendrimers were conjugated with alkylcarboxylate groups as linker to enhance the transfection efficiency while maintaining their low cell toxicity. First, 10-bromodecanoic acid was covalently attached to all available surface primary amines of PPI G2 and G3 to increase their lipophilicity. In the subsequent step, PPIs were conjugated to the alkylcarboxylate groups of alkylcarboxylate-PPI derivatives to increase the number of surface primary amines. Physicochemical properties of modified PPIs were determined. Transfection experiments (using both luciferase and green fluorescent protein (GFP)- expressing plasmids) and cytotoxicity assay were performed to evaluate the efficiency of the final derivatives. Fabricated vectors condensed DNA effectively so that polyplexes with appropriate size (below 155 nm) and positive surface charge were constructed. Cross-linked low molecular weight PPIs (G2 or G3) with decanoate linkage increased transfection efficiency significantly while maintaining the low cytotoxicity. PPI G2 derivative exhibited increased buffering capacity which is believed to be responsible for better proton sponge mechanism leading to higher transfection efficiency. Our results indicated that oligomerization of low molecular weight PPI (PPI G2-alkyl-PPI G2 conjugate) could be an approach to increase the transfection efficiency and to lower the cytotoxicity of low molecular weight polycations.

Binding Affinity, Cellular Uptake, and Subsequent Intracellular Trafficking of the Nano-Gene Vector P123-PEI-R13

A nano-gene vector PEI-P123-R13 was synthesized by cross-linking low molecular weight PEI with P123 and further coupling bifunctional peptide R13 to the polymer for targeting tumor and increasing cellular uptake. The binding assessment of R13 toαvβ3 positive cells was performed by HRP labeling. The internalization pathways of P123-PEI-R13/DNA complexes were investigated based on the effect of specific endocytic inhibitors on transfection efficiency. The mechanism of intracellular trafficking was investigated based on the effect of endosome-lysosome acidification inhibitors, cytoskeleton, and dynein inhibitors on transfection efficiency. The results indicated that the bifunctional peptide R13 had the ability of binding toαvβ3 positive cellsin vitro. The modification of P123-PEI-R13 with R13 made it display new property of internalization. P123-PEI-R13/DNA complexes were conducted simultaneously via clathrin-mediated endocytosis, caveolin-mediated endocytosis, macropinocytosis, and possible energy-independent route. After internalization, P123-PEI-R13/DNA complexes could escape from the endosome-lysosome system because of its acidification and further took microtubule as the track and dynein as the dynamic source to be transported toward the microtubule (+) end, to wit nucleus, under the action of microfilament, and with the aid of intermediate filament.

Characterization and Adsorption Performance of Polyurethane Foam Synthesized From Guluronic Acid Rich Sodium Alginate

Polyurethane foams based on guluronic acid(G)-rich sodium alginate(PF-SA) were synthesized by using cross-linking low molecular weight G-rich alginic acid(LG-HA)with hexamethylene diisocyanate(HDI). The prepared PF-SA was characterized and its adsorption performance of methylene blue(MB) in aqueous solution was investigated by XRD, FTIR, SEM, BET. The results show that the dosage of HDI and the concentration of LG-HA have a significant impact on the morphology and the microstructure of PF-SA; PF-SA with three-dimensional interconnected pore structure may be prepared when the molar ratio of HDI to the monomer unit of LG-HA was in the range of 1: 4 to1: 3, the concentration of LGHA was in the range of 0.08-0.1 g/m L; this PF-SA is effective for the adsorption of MB: for a solution with concentration of 100 mg/L MB, the adsorption equilibrium can be reached in 30-160 min at room temperature. The removal efficiency of MB was as high as 99%.

Removal of cadmium from aqueous solution using low molecular weight chitosan derivative

A 23 factorial design was used to examine the sorption of Cd2+ onto cross-linked low molecular weight chitosan pyruvic acid derivative. Three factors and two levels of solution pH (A) (6.0 or 10.0), temperature (B) (45 or 70°C) and Cd(II) concentration (C) (1 or 3mg/L) were considered. Batch mode system was employed with 0.05g of the sorbent and 25mL of Cd(II) solution. The efficiency of cadmium removal during an exposition time of 4h was then evaluated. The factors and their interaction effect on the cadmium removal efficiency followed the order: Cd(II) concentration>solution pH>interaction between solution pH and Cd(II) concentration>interaction between solution pH, temperature and Cd(II) concentration. Langmuir isotherm model was the best isotherm model. The Pseudo second order fitted well the kinetic data. The thermodynamic studies revealed the nature of the cadmium sorption.

Tris[2-(Acryloyloxy)Ethyl]Isocyanurate Cross-Linked Polyethylenimine Enhanced Exon-Skipping of Antisense 2′-Omethyl Phosphorothioate Oligonucleotide in vitro and in vivo

Branched poly(ester amine)s (PEAs) based on tris[2-(acryloyloxy)ethyl]isocyanurate (TAEI) cross-linked low molecular weight polyethylenimine (LPEI, Mw: 0.8k/1.2k/2.0k) polymers have been evaluated for their ability to deliver antisense 2′-O-methyl phosphorothioate RNA (2′-OMePS) through in vitro and in dystrophic mdx mice. Almost all PEAs improved exon-skipping of 2′-OMePS both in vitro and in vivo. Especially the PEAs composed of PEI 2.0k (C series) enhanced 2′-OMePS delivery more effectively than PEI 0.8k or 1.2k-based series using a GFP reporter-based C2C12 myoblast culture system and in mdx mice. The highest efficiency of targeted exon-skipping of 2′-OMePS was obtained by PEA C14 [TAEI-PEI 2.0k (1:4)] with up to 6 fold increase compared with 2′-OMePS only in mdx mice via intramuscular injection without increased muscle damage. Enhanced exon-skipping and lower toxicity highlight the potential of this series biodegradable PEAs as safe and efficient 2′-OMePS delivery vectors for treating diseases such as muscular dystrophy with splicing modulation.

Cell transfection with a β-cyclodextrin-PEI-propane-1,2,3-triol nanopolymer.

Successful gene therapy necessitates safe and efficient gene transfer. This article describes the use of a cationic polymer, which was synthesized by cross-linking low molecular weight branched poly(ethylenimine) (PEI) with both β-cyclodextrin and propane-1,2,3-triol, for efficient and safe non-viral gene delivery. Experimentation demonstrated that the polymer had a pH buffering capacity and DNA condensing ability comparable to those of PEI 25 kDa. In B16-F0 cells, the polymer increased the transfection efficiency of naked DNA by 700-fold and yielded better transfection efficiencies than Fugene HD (threefold higher) and PEI 25 kDa (fivefold higher). The high transfection efficiency of the polymer was not affected by the presence of serum during transfection. In addition to B16-F0 cells, the polymer enabled efficient transfection of HepG2 and U87 cells with low cytotoxicity. Our results indicated that our polymer is a safe and efficient transfection reagent that warrants further development for in vitro, in vivo and clinical applications.

Biscarbamate cross-linked low molecular weight Polyethylenimine polycation as an efficient intra-cellular delivery cargo for cancer therapy

BackgroundA challenge in gene therapy is the efficient delivery of DNA/siRNA to the diseased cells. The physicochemical characteristics of siRNA, such as high molecular weight, negative charges and hydrophilic nature—prevent passive diffusion across the plasma membrane for most cells. A therapeutically feasible carrier for intra-cellular delivery of gene materials should accomplish a series of tasks such as: condensing nucleic acid, protecting nucleic acid from leaking in vivo, facilitating endosome escape and releasing DNA/siRNA to the target site. To meet these requirements, an efficient gene vector based on polycation synthesis for siRNA delivery both in vitro and in vivo was developed.ResultsThe polymer was synthesized by 1, 4-butanediol bis (chloroformate) and PEI 800 Da to form PEI-Bu which could condense siRNA at the N/P ratio of 38.35 or above. The size of the nanoparticles was 100–300 nm and zeta potential was in the range of 10–30 mV at different N/P ratios. The nanoparticles can achieve the ability of cellular uptake and the silencing efficiency was about 46.63% in SMMC-7721 cell line which was generated to stably express GL3 luciferase gene. The cytotoxicity of the polyplex nanoparticles was almost negligible on SMMC-7721 cells by MTT assay, indicating that the reduced luciferase expression was the effect of RNAi, not the influence of cytotoxicity of polyplexes. The polyplex nanoparticle formulated by PEI-Bu and siRNA at N/P ratio of 115.05 was injected into the SMMC-7721 tumor bearing mice locally and the expression of luciferase can reduce to 63.17% compared with control group.ConclusionsResults in this study suggested that PEI-Bu polycation might provide a promising solution for siRNA delivery and had the potential in anti-tumor gene therapy.

Lead removal onto cross-linked low molecular weight chitosan pyruvic acid derivatives

Adsorption capacity of cross-linked low molecular weight chitosan pyruvic acid derivatives CSnPA-GLA (n=8, 11) were examined by employing 23 factorial design method. Three (3) factors and two (2) levels of adsorbent dose (A) (0.05 and 0.1g), adsorbent type (B) (CS8PA-GLA and CS11PA-GLA) and concentration of lead solution (C) (1 and 3mg/L) were considered. From the statistical analysis, all the main parameters (A, B and C) and some interactions of the main parameters (AC and ABC) had influence on the adsorption process at 5% significance level. The adsorption process was greatly influenced by the adsorbent type (B). The adsorption equilibrium results correlated well with the Freundlich isotherm model. The adsorption kinetic data also correlated well with the pseudo second order. The thermodynamic studies also revealed that the nature of lead adsorption was spontaneous and endothermic. The findings suggest that CS8PA-GLA is better than CS11PA-GLA for lead sorption.

Hyaluronic acid-coated chitosan nanoparticles: Molecular weight-dependent effects on morphology and hyaluronic acid presentation

Chitosan nanoparticles are popular carriers for the delivery of macromolecular payloads, e.g. nucleic acids. In this study, nanoparticles were prepared via complexation with triphosphate (TPP) anions and were successively coated with hyaluronic acid (HA). Key variables of the preparative process (e.g. chitosan and HA molecular weight) were optimised in view of the maximisation of loading with DNA, of the Zeta potential and of the dimensional stability, and the resulting particles showed excellent storage stability.We have focused on the influence of chitosan molecular weight on nanoparticle properties. Larger molecular weight increased their porosity (=decreased cross-link density), and this caused also larger dimensional changes in response to variations in osmotic pressure or upon drying. The dependency of nanoparticle porosity on chitosan molecular weight had a profound effect on the adsorption of HA on the nanoparticles; HA was apparently able to penetrate deeply into the more porous high molecular weight (684kDa) chitosan nanoparticles, while it formed a corona around those composed of more densely cross-linked low molecular weight (25kDa) chitosan. Atomic Force Microscopy (AFM) allowed not only to highlight the presence of this corona, but also to estimate its apparent thickness to about 20–30nm (in a dry state). The different morphology has a significant effect on the way HA is presented to biomolecules, and this has specific relevance in relation to interactions with HA receptors (e.g. CD44) that influence kinetics and mechanism of nanoparticle uptake.Finally, it is worth to mention that chitosan molecular weight did not appear to greatly affect the efficiency of nanoparticle loading with DNA, but significantly influenced its chitosanase-triggered release, with high molecular chitosan nanoparticles seemingly more prone to degradation by this enzyme.

Biscarbamate cross-linked low molecular weight PEI for delivering IL-1 receptor antagonist gene to synoviocytes for arthritis therapy

Cytoxicity is an essential concern for polyethyleneimine 25 kDa (PEI 25 kDa), a widely reported, highly effective transfection agent used in gene delivery. In our recent experiments, Small molecular weight cross-linked poly(ethylene imine) by biscarbamate linkage (PEI–Bu) (Mn: 3278, Mw: 4289) can reduce target cell apoptosis induced by polycationic transfection, and has almost the same DNA condensation capability as PEI 25 kDa. PEI–Bu showed significantly higher activity and lower cytotoxicity than PEI 25 kDa in transfecting the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1Ra) gene to rat synoviocytes, an optimal target for arthritis treatment. The expression of IL-1Ra in synoviocytes then suppresses the expression of metalloproteases 13 (MMP13) gene, which is responsible for cartilage destruction regulated by IL-1β in arthritis. In conclusion, PEI–Bu is a promising tool for delivering IL-1Ra gene to synoviocytes for arthritis therapy.

Degradable copolymer based on amphiphilic N-octyl-N-quatenary chitosan and low-molecular weight polyethylenimine for gene delivery

BackgroundChitosan shows particularly high biocompatibility and fairly low cytotoxicity. However, chitosan is insoluble at physiological pH. Moreover, it lacks charge, so shows poor transfection. In order to develop a new type of gene vector with high transfection efficiency and low cytotoxicity, amphiphilic chitosan was synthesized and linked with low-molecular weight polyethylenimine (PEI).MethodsWe first synthesized amphiphilic chitosan – N-octyl-N-quatenary chitosan (OTMCS), then prepared degradable PEI derivates by cross-linking low-molecular weight PEI with amphiphilic chitosan to produce a new polymeric gene vector (OTMCS–PEI). The new gene vector was characterized by various physicochemical methods. We also determined its cytotoxicity and gene transfecton efficiency in vitro and in vivo.ResultsThe vector showed controlled degradation. It was very stable and showed excellent buffering capacity. The particle sizes of the OTMCS–PEI/DNA complexes were around 150–200 nm with proper zeta potentials from 10 mV to 30 mV. The polymer could protect plasmid DNA from being digested by DNase I at a concentration of 2.25 U DNase I/μg DNA. Furthermore, they were resistant to dissociation induced by 50% fetal bovine serum and 1100 μg/mL sodium heparin. OTMCS–PEI revealed lower cytotoxicity, even at higher doses. Compared with PEI 25 KDa, the OTMCS–PEI/DNA complexes also showed higher transfection efficiency in vitro and in vivo.ConclusionOTMCS–PEI was a potential candidate as a safe and efficient gene vector for gene therapy.

Poly(oligo-D-arginine) With Internal Disulfide Linkages as a Cytoplasm-sensitive Carrier for siRNA Delivery

Small interfering RNA (siRNA) has emerged as a therapeutic strategy for various diseases due to its target-specific gene silencing; however, its relatively high molecular weight, negative charge, and low stability hamper in vitro and in vivo applications. Approaches to overcome those drawbacks have relied on nonviral siRNA carriers based on cationic polymers or peptides. Nevertheless, cationic polymer-based siRNA carriers have yet to resolve intrinsic problems such as cytotoxicity and immunogenicity. An environment-sensitive carrier was recently proposed to enhance siRNA bioactivity and to reduce the carrier safety issues. Only a few studies, however, have shown cytoplasm-sensitive dissociation of the polyplex. In the present study, we clearly demonstrated decondensation of siRNA/poly(oligo-D-arginine) polyplex in the cytoplasm in response to intracellular glutathione (GSH) and the enhanced bioactivity of siRNA against VEGF (siVEGF) used as a model both in vitro and in an animal model. Reducible poly(oligo-D-arginine) (rPOA) rapidly dissociated in the cytoplasm, resulting in fast siRNA release to its target location while maintaining siRNA bioactivity both in vitro and in vivo.

Combination of adenovirus and cross-linked low molecular weight PEI improves efficiencyof gene transduction

Recombinant adenovirus (Ad)-mediated gene therapy is an exciting novel strategy incancer treatment. However, poor infection efficiency with coxsackievirus and adenovirusreceptor (CAR) down-regulated cancer cell lines is one of the major challenges for itspractical and extensive application. As an alternative method of viral gene delivery, anon-viral carrier using cationic materials could compensate for the limitation ofadenovirus. In our study, adenovectors were complexed with a new synthetic polymerPEI-DEG-bis-NPC (PDN) based on polyethylenimine (PEI), and then the properties of thevehicle were characterized by measurement of size distribution, zeta potential andtransmission electron microscopy (TEM). Enhancement of gene transduction byAd/PDN complexes was observed in both CAR-overexpressing cell lines (A549) andCAR-lacking cell lines (MDCK, CHO, LLC), as a result of facilitating binding and celluptake of adenoviral particles by the cationic component. Ad/PDN complexesalso promoted the inhibition of tumor growth in vivo and prolonged the survivaltime of tumor-bearing mice. These data suggest that a combination of viral andnon-viral gene delivery methods may offer a new approach to successful cancer genetherapy.