OBJECTIVETo evaluate the impact of surface modification on the DNA-binding ability of nano-hydroxyapatite (nHA).

METHODSChemical co-precipitation-hydrothermal synthesis was utilized to prepare the nHA particles, and polyethylenimine (PEI) was used for surface modification of the nHA. Transmission electron microscopic (TEM) observation and zeta potential detection of the nHA were carried out before and after surface modification. The abilities of the nanoparticles, at different pH values and different concentrations, for DNA-binding and DNA protection against nuclease digestion were assessed before and after surface modification by electrophoresis.

RESULTSTEM observation showed a short rod-like morphology of PEI-modified nHA with uniform particle size and good dispersion; the nHA without the modification tended to aggregate with poor dispersion. With a positive zeta potential, the PEI-modified nHA showed an obviously enhanced ability of DNA binding at different pH values and concentrations, with strong capacity to protect the DNA against Dnase I digestion. At the concentration of 250 µg/ml and a pH value of 7.0, the nHA-PEI showed an optimal efficiency of DNA-binding and DNA protection.

CONCLUSIONnHA with surface modification by PEI can serve as an effective vector for DNA binding and transfer.

Amino Acid Motifs ; DNA ; chemistry ; Durapatite ; chemistry ; Gene Transfer Techniques ; Genetic Vectors ; Nanoparticles ; chemistry ; Polyethyleneimine ; chemistry

OBJECTIVETo develop a novel non-viral gene delivery vector based on PEI-beta-CyD as backbone modified with aspirin, and to identify its physicochemical characters.

METHODS1, 1-carbonyldiimidazole (CDI) was used to bind aspirin onto PEI-beta-CyD to form PEI-beta-CyD-ASP. (1)H-NMR, FT-IR, UV and XRD were used to confirm the polymer structure. The ability of condensation was demonstrated by gel retardation assay. MTT assay was used to test the cell viability in B16, Hela and A293 cell lines. Transfection efficiency of the polymer was tested in B16 cells.

RESULTThe structure of PEI-beta-CyD-ASP was confirmed by (1)H-NMR, FT-IR, UV and XRD, which efficiently condensed plasmid DNA at the N/P ratio of 4. The copolymer showed low cytotoxicity and high transfection efficiency in B16 cells.

CONCLUSIONThe synthesized aspirin-PEI-beta-CyD might be a potential gene delivery vector.

Aspirin ; chemistry ; Cell Line ; Gene Transfer Techniques ; Genetic Therapy ; methods ; Humans ; Polyethyleneimine ; chemistry ; beta-Cyclodextrins ; chemistry

OBJECTIVETo develop a novel vector for gene delivery with low molecular weight polyethylenimine grafted to the natural polysaccharide and conjugated to folic acid (LNT-PEI-FA).

METHODSThe properties of LNT-PEI-FA were characterized by (1)H-NMR, FT-IR and TGA, respectively. The particle size of LNT-PEI-FA/DNA complex was measured. The DNA binding ability of LNT-PEI-FA was detected by gel electrophoresis retardation assay.

RESULTThe particle size of LNT-PEI-FA/DNA complex was about 200 nm. Gel electrophoresis showed that at N/P ratio of 1.8 (W/W) the polymer was able to completely condense DNA. In vitro experiments showed a high efficiency of gene transfection in A293 and B16 cell lines.

CONCLUSIONA novel non-viral vector LNT-PEI-FA was successfully synthesized and characterized, which may be applied in gene transfection research in the future.

Cell Line ; Folic Acid ; chemistry ; Gene Transfer Techniques ; Genetic Therapy ; methods ; Humans ; Lentinan ; chemistry ; Polyethyleneimine ; chemistry

OBJECTIVETo develop a novel gene delivery vector with poly-aspartamide-glutamic acid and polyethylenimine as the backbone.

METHODSalpha, beta-poly-(N-2-hydroxypropyl)-D, L-aspartamide-glutamic acid (PHPAG) was synthesized and low molecular weight polyethylenimine (PEI 1.8 kDa) was grafted to form PHPAG-PEI 1800. Chemical and biological characterization of the polymer was identified.

RESULTThe polymer was confirmed by (1)H-NMR, and the molecular weight was about 1.2 x 10(4). The ability of DNA binding was showed by gel retardation assay at N/P ratio of 3. 5. MTT assay showed that the polymer was non toxic in COS-7 and A293 cell lines. In vitro test demonstrated that it had high transfection efficiency in B16 and Hela cell lines.

CONCLUSIONPHPAG-PEI 1800 was successfully synthesized,which might be a potential vector for gene delivery.

Cell Line ; Gene Transfer Techniques ; Genetic Therapy ; methods ; Glutamic Acid ; chemistry ; Humans ; Peptides ; chemistry ; Polyethyleneimine ; chemistry

Polyelectrolyte with a large number of cations or anions could precipitate the oppositely charged proteins to form polyelectrolyte-protein complexes, which then aggregated to form larger particles via electrostatic attraction or hydrophobic interaction. The precipitation was affected by the molecular weight and concentration of the polyelectrolyte as well as the ionic strength and pH of the solution. The use of precipitation is an efficient method for selective separation of proteins from crude biological mixtures in the downstream processes of bioengineering.
Acrylic Resins ; chemistry ; Chemical Precipitation ; Electrolytes ; chemistry ; Polyethyleneimine ; chemistry ; Protein Binding ; Proteins ; isolation & purification

We prepared silver nanoparticles/polyethyleneimine-reduction graphene oxide (AgNP/rGO-PEI) composite materials, and evaluated their quality performance in our center. Firstly, we prepared AgNP/rGO-PEI, and then analysed its stability, antibacterial activity, and cellular toxicity by comparing the AgNP/rGO-PEI with the silver nanoparticles (PVP/AgNP) modified by polyvinylpyrrolidone. We found in the study that silver nanoparticles (AgNP) distributed relatively uniformly in AgNP/rGO-PEI surface, silver nanoparticles mass fraction was 4.5%, and particle size was 6-13 nm. In dark or in low illumination light intensity of 3 000 lx meter environment (lux) for 10 days, PVP/AgNP aggregation was more obvious, but the AgNP/rGO-PEI had good dispersibility and its aggregation was not obvious; AgNP/rGO-PEI had a more excellent antibacterial activity, biological compatibility and relatively low biological toxicity. It was concluded that AgNP/rGO-PEI composite materials had reliable quality and good performance, and would have broad application prospects in the future.
Anti-Bacterial Agents ; chemistry ; Graphite ; chemistry ; Light ; Nanoparticles ; chemistry ; Oxides ; chemistry ; Particle Size ; Polyethyleneimine ; chemistry ; Silver Compounds ; chemistry

The study was aimed to investigate the possibility of enhancing transfection efficiency of branched polyethylenimine (BPEI) in HeLa cells by hydrophobic tail of bee venom peptide (melittin). Hydrophobic tail of melittin was synthesized and its membrane permeable activity was evaluated by hemolysis test. The peptide was mixed with BPEI and the transfection efficiency was determined in HeLa cells by using green fluorescent protein gene (GFP) as a reporter gene. The cytotoxicity of the mixture was analyzed by MTT assay at 24 hours after transfection. The results indicated that the synthesized peptide had permeable activity leading to hemolysis in both neutral and acidic solution. At optimal condition, the peptide could significantly improve the transfection efficiency of BPEI and the cytotoxicity of the mixture was lower than BPEI itself. It is concluded that hydrophobic tail of melittin may be a potential enhancer to improve transfection efficiency mediated by cationic polymers in difficult to transfect cells.
HeLa Cells ; Humans ; Hydrophobic and Hydrophilic Interactions ; Melitten ; chemistry ; genetics ; Peptides ; chemistry ; Polyethyleneimine ; pharmacology ; Transfection

Polyethylenimine (PEI) is a kind of nanometer nonviral vector frequently applied in gene transfection. It is simple and easy to prepare and to modify and relatively safe compared to viral vectors. In recent years, PEI has been utilized in many research areas for gene delivery to stem cells in vitro or targeted gene delivery to cells in the brain. This review reveals that the cytotoxicity and low transfection efficiency of PEI requires to be improved. However brain-targeted modification indicates the promising prospect of PEI for gene therapy in cerebrovascular diseases.
Genetic Therapy ; Genetic Vectors ; Humans ; Nanostructures ; chemistry ; Polyethyleneimine ; chemistry ; Stem Cell Transplantation ; methods ; Transfection ; methods

In vitro gene delivery, polyethyleneimine (PEI) has been described as one of the most efficient nonviral vector. Herein the formation mechanism of PEI/DNA complexes is elucidated. The transition phase of "bead-on-string" structure in the formation of complexes was supposed to exist through spectroscopy, electrophoresis and transmission electron microscopy (TEM) technology. The construction of PEI/DNA complexes is related closely to the characteristics of PEI and DNA plasmid. As well as the dominant electrostatic effects, the nonelectrostatic interactions were thought to be partially responsible for the presence of PEI/DNA complexes even in the high ionic strength. The surface charge of complexes particles increased with the N/P ratio, but the absolute value of zeta potential was lower at the N/P ratio of 8 and 12, perhaps attributed to the use of larger DNA plasmid. As a result, the repulsion between particles was decreased and prone to aggregate to the structure like a clustered grape-string in the solution. Interestingly, contrast to the formation behavior of complexes, the PEI/DNA complexes aggregated primarily due to hydrophobic interactions while electrostatic attractions play a little role in the complexes particles aggregation in different concentrations of salt solutions. Comparable transfection efficiency in HepG2 cells was observed for the Lipofectamine 2000 and PEI/DNA complexes at the N/P ratio of 12, and showed that larger or aggregable complexes could transfect the cells in some different mechanisms.
DNA ; genetics ; Drug Carriers ; Gene Transfer Techniques ; Genetic Therapy ; Polyethyleneimine ; chemistry ; Transfection

Apoptosis is a physiologically essential mechanism of cell and plays an important role in reducing the development and progression of tumors. The appealing strategy for cancer therapy is to target the lesions that induce apoptosis in cancer cells. Survivin, the smallest member of the mammalian inhibitors of the apoptosis protein family, is upregulated in various malignancies to protect cells from apoptosis. Survivin knockdown could induce cancer cell apoptosis and inhibit tumor-angiogenesis. Survivin expression would be silenced by microRNA (miRNA)-mediated RNA interference. However, noninvasive and tissue-specific gene delivery techniques remain absent recently and the utilizations of miRNA expression vectors have been limited by inefficient delivery technique, especially in vivo. On the other hand, safe and promising technologies of gene transfection would be valuable in clinical gene therapy. Successful treatment of gene transfer method would lead to a new and readily available approach in the anticancer research. Sonoporation is an alternative technique of gene delivery that uses ultrasound targeted microbubble destruction to create pores in the cell membrane. Based on our previous studies, in this article, we postulated that the transfection of miRNA could be mediated by the combination of sonoporation and polyethylenimine (PEI) which was one of the most effective poly-cationic gene vectors and enhance the endocytosis of plasmids DNA and hypothesized that the gene silencing and apoptosis induction with miRNA targeting human Survivin would be improved by this novel technique. In our opinion, this novel combination of sonoporation and PEI could enhance targeted gene delivery effectively and might be a feasible, novel candidate for gene therapy.
Genetic Therapy ; methods ; Humans ; Inhibitor of Apoptosis Proteins ; genetics ; MicroRNAs ; genetics ; Neoplasms ; therapy ; Polyethyleneimine ; chemistry ; Transfection ; methods