Physicochemical characterization of poly(L-lactic acid) and poly(D,L-lactide-co-glycolide) nanoparticles with polyethylenimine as gene delivery carrier (original) (raw)
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Journal of Controlled Release, 2001
The purpose of the present work was to produce and characterize poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) nanoparticles (size lower than 300 nm) containing a high loading of plasmid DNA in a free form or co-encapsulated with either poly(vinyl alcohol) (PVA) or poly(vinylpyrrolidone) (PVP). The plasmid alone or with PVA or PVP was encapsulated by two different techniques: an optimized w/o/w emulsion-solvent evaporation technique as well as by a new w/o emulsion-solvent diffusion technique. Particle size, ζ potential, plasmid DNA loading and in vitro release were determined for the three plasmid-loaded formulations. The influence of the initial plasmid loadings (5, 10, 20 μg plasmid DNA/mg PLA-PEG) on those parameters was also investigated. The plasmid loaded into the nanoparticles and released in vitro was quantified by fluorimetry and the different molecular forms were identified by gel electrophoresis. PLA-PEG nanoparticles containing plasmid DNA in a free form or co-encapsulated with PVA or PVP were obtained in the range size of 150–300 nm and with a negative ζ potential, both parameters being affected by the preparation technique. Encapsulation efficiencies were high irrespective of the presence of PVA or PVP (60–90%) and were slightly affected by the preparation technique and by the initial loading. The final plasmid DNA loading in the nanoparticles was up to 10–12 μg plasmid DNA/mg polymer. Plasmid DNA release kinetics varied depending on the plasmid incorporation technique: nanoparticles prepared by the w/o diffusion technique released their content rapidly whereas those obtained by the w/o/w showed an initial burst followed by a slow release for at least 28 days. No significant influence of the plasmid DNA loading and of the co-encapsulation of PVP or PVA on the in vitro release rate was observed. In all cases the conversion of the supercoiled form to the open circular and linear forms was detected. In conclusion, plasmid DNA can be very efficiently encapsulated, either in a free form or in combination with PVP and PVA, into PLA-PEG nanoparticles. Additionally, depending on the processing conditions, these nanoparticles release plasmid DNA either very rapidly or in a controlled manner.
Tropical Journal of Pharmaceutical Research, 2018
Purpose: To compare the gene delivery effectiveness of plasmid DNA (pDNA) encapsulated within poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles with that adsorbed on PLGA nanoparticles. Methods: PLGA nanoparticles were prepared using solvent-evaporation method. To encapsulate pDNA within the particles, it was first complexed with cetyltrimethylammonium bromide (CTAB) and then added to the oil phase during the synthesis. For the adsorption, PLGA nanoparticles were first modified with either CTAB or chitosan and then pDNA was adsorbed on the particle surface by electrostatic interaction. Results: Nanoparticles encapsulating pDNA exhibited better plasmid loading and protection with significantly lower burst release (p < 0.05) compared to that of the nanoparticles with adsorbed plasmid. Cell uptake of chitosan-modified nanoparticles by murine neuroblastoma (N2a) cells was significantly (p < 0.05) higher than that of chitosan-free nanoparticles. Nanoparticles encapsulating pDNA showed higher transfection efficiency (p < 0.05) in N2a cells. Conclusion: Encapsulation of pDNA within PLGA nanoparticles presents a potential strategy for gene delivery that is superior to pDNA adsorbed on the nanoparticle surface. In addition, encapsulation keeps the particle surface free for further modifications such as the addition of targeting ligands.
Journal of Biotechnology, 2007
The cationic polylactic acid (PLA) nanoparticle has emerged as a promising non-viral vector for gene delivery because of its biocompatibility and biodegradability. However, they are not capable of prolonging gene transfer and high transfection efficiency. In order to achieve prolonged delivery of cationic PLA/DNA complexes and higher transfection efficiency, in this study, we used copolymer methoxypolyethyleneglycol-PLA (MePEG-PLA), PLA and chitosan (CS) to prepare MePEG-PLA-CS NPs and PLA-CS NPs by a diafiltration method and prepared NPs/DNA complexes through the complex coacervation of nanoparticles with the pDNA. The object of our work is to evaluate the characterization and transfection efficiency of MePEG-PLA-CS versus PLA-CS NPs. The MePEG-PLA-CS NPs have a zeta potential of 15.7 mV at pH 7.4 and size under 100 nm, while the zeta potential of PLA-CS NPs was only 4.5 mV at pH 7.4. Electrophoretic analysis suggested that both MePEG-PLA-CS NPs and PLA-CS NPs with positive charges could protect the DNA from nuclease degradation and cell viability assay showed MePEG-PLA-CS NPs exhibit a low cytotoxicity to normal human liver cells. The potential of PLA-CS NPs and MePEG-PLA-CS NPs as a non-viral gene delivery vector to transfer exogenous gene in vitro and in vivo were examined. The pDNA being carried by MePEG-PLA-CS NPs, PLA-CS NPs and lipofectamine could enter and express in COS7 cells. However, the transfection efficiency of MePEG-PLA-CS/DNA complexes was better than PLA-CS/DNA and lipofectamine/DNA complexes by inversion fluorescence microscope and flow cytometry. It was distinctively to find that the transfection activity of PEGylation of complexes was improved. The nanoparticles were also tested for their ability to transport across the gastrointestinal mucosa in vivo in mice. In vivo experiments showed obviously that MePEG-PLA-CS/DNA complexes mediated higher gene expression in stomach and intestine of BALB/C mice compared to PLA-CS/DNA and lipofectamine/DNA complexes. These results suggested that MePEG-PLA-CS NPs have favorable properties for non-viral gene delivery.
Iranian Journal of Pharmaceutical Research : IJPR, 2019
Tri-block poly (lactide) poly(ethylene glycol) poly(lactide) (PLA–PEG–PLA) copolymers are among the most attractive nano-carriers for gene delivery into mammalian cells, due to their biocompatibility and biodegradability properties. However, the low efficiency of the gene delivery by these copolymers is an obstacle to gene therapy. Here, we have investigated nanoparticles formulated using the polyethylenimine (PEI) associated with PLA-PEG-PLA copolymer for efficient DNA encapsulation and delivery. PLA-PEG-PLA/DNA and PLA-PEG-PLA/PEI/DNA nanoparticles with different concentrations of PEI were prepared by the double emulsion-solvent evaporation technique. PLA-PEG-PLA/PEI/DNA were characterized for particle size, zeta potential, morphology, biocompatibility, DNA protection, DNA release, and their ability for gene delivery into MCF-7 cells. We found that enhancing the mass ratio of PEI: (PLA-PEG-PLA) (w/w%) in the PLA-PEG-PLA/PEI/DNA nanoparticles results in an increase in particles siz...
Journal of Controlled Release, 1999
This study describes the influence of polymer type, surfactant type / concentration, and target drug loading on the particle size, plasmid DNA (pDNA) structure, drug loading efficiency, in vitro release, and protection from DNase I degradation of poly(D,L-lactide-co-glycolide) (PLGA) microspheres containing poly(L-lysine) (PLL) complexed pDNA. PLGA microspheres containing pDNA-PLL were prepared using the water-in-oil-in-water (w-o-w) technique with poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) as surfactants in the external aqueous phase. A complex ratio of 1:0.33 (pDNA-PLL, w / w) enhanced the stability of pDNA during microsphere preparation. Higher pDNA-PLL loading efficiency (46.2%) and supercoiled structure (64.9%) of pDNA were obtained from hydrophobic PLGA (M 31 000) microspheres compared with w hydrophilic PLGA or low-molecular-weight PLGA microspheres. The particle size decreased from 6.6 to 2.2 mm when the concentration of PVA was increased from 1 to 7%. At the same concentration of surfactant, PVA stabilized microspheres showed higher pDNA-PLL loading efficiency (46.2%) than PVP stabilized microspheres (24.1%). Encapsulated pDNA in PLGA microspheres was protected from enzymatic degradation and maintained in the supercoiled form. The pDNA-PLL microspheres showed in vitro release of 95.9 and 84.9% within 38 days from the low-molecular-weight PLGA and hydrophilic PLGA microspheres, respectively, compared to 54.2% release from the hydrophobic, higher-molecular-weight PLGA microspheres. The results suggest loading and release of pDNA-PLL complex can be influenced by surfactant concentration and polymer type.
Nanoparticles have been widely used for nonviral gene delivery. Recently, cationic hybrid nanoparticles consisting of two different materials were suggested as a promising delivery vehicle. In this study, nanospheres with a poly(d,l-lactic-co-glycolic acid) (PLGA) core and cationic lipid shell were prepared, and the effect of cationic lipid concentrations on the properties of lipid polymer hybrid nanocarriers investigated. Lipid–polymer hybrid nanospheres (LPHNSs) were fabricated by the emulsion-solvent evaporation method using different concentrations of cationic lipids and characterized for size, surface charge, stability, plasmid DNA-binding capacity, cytotoxicity, and transfection efficiency. All LPHNSs had narrow size distribution with positive surface charges (ζ-potential 52–60 mV), and showed excellent plasmid DNA-binding capacity. In vitro cytotoxicity measurements with HEK293T, HeLa, HaCaT, and HepG2 cells also showed that LPHNSs exhibited less cytotoxicity than conventional transfection agents, such as Lipofectamine and polyethyleneimine–PLGA. As cationic lipid concentrations increased, the particle size of LPHNSs decreased while their ζ-potential increased. In addition, the in vitro transfection efficiency of LPHNSs increased as lipid concentration increased.
European Journal of Pharmaceutics and Biopharmaceutics, 2010
The aim of the present study is to evaluate the effect of polyethylene glycol (PEG) chain organization on various physicochemical aspects of drug delivery from poly(D, L-lactide) (PLA) based nanoparticles (NPs). To reach that goal, two different pegylated polymers of poly(D, L-lactide) (PLA) were synthesized. Polymers used in this study are grafted ones in which PEG was grafted on PLA backbone at 7% (mol/mol of lactic acid monomer), PEG7%-g-PLA, and multiblock copolymer of both PLA and PEG, (PLA-PEG-PLA)n with nearly similar PEG insertion ratio and the same PEG chain length. Blank and ibuprofen-loaded NPs were prepared from both polymers and their properties were compared to PLA homopolymer NPs as a control. Encapsulation efficiency of ibuprofen was found to be approximately 25% for (PLA-PEG-PLA)n NPs and approximately 80% for PEG7%-g-PLA NPs. (PLA-PEG-PLA)n NPs either blank or loaded showed larger hydrodynamic diameter (approximately 200 nm) than PEG7%-g-PLA NPs (approximately 135 nm). A significant difference was observed in the amount of PVA associated with the surface of both NPs where 3.6% and 0.4% (wt/wt) were found on the surface of PEG7%-g-PLA and (PLA-PEG-PLA)n NPs, respectively. No observed difference in zeta potential values for both NPs formulations was found. DSC showed the existence of the drug in a crystalline state inside NPs matrix irrespective of the type of polymer used with either shifting or/and broadening of the drug melting endotherm. Both AFM phase imaging and XPS studies revealed the possibility of existence of more PEG chains at the surface of grafted polymer NPs than (PLA-PEG-PLA)n during NPs formation. The in vitro release behavior showed that (PLA-PEG-PLA)n NPs exhibited faster release rates than PEG7%-g-PLA NPs. The physicochemical differences obtained between both polymers were probably due to different chain organization during NPs formulation. Such pegylated NPs made from these two different polymers might find many applications, being able to convert poorly soluble, poorly absorbed substances into promising drugs, improving their therapeutic performance, and helping them reach adequately their target area. Our results suggest that the properties of pegylated PLA-based NPs can be tuned by proper selection of both polymer composition and polymer architecture.
Journal of the Brazilian Chemical Society, 2011
Nanopartículas de poli(ácido lactico) (PLA) foram preparadas para serem usadas como plataformas potenciais em sistemas de vacinas. PLA comercial de elevado peso molecular (PLA HMW ) com M w 1,5 × 10 5 e PLA de baixo peso molecular (PLA LMW ) com M w 9,3 × 10 3 foram obtidos por policondensação direta a partir de D,L ácido lático e usados para preparar nanopartículas pelo método de deslocamento de solvente. O efeito do peso molecular nas propriedades físico-químicas dos polímeros, nas dispersões das nanopartículas e na quantidade de adsorção de ovalbumina (OVA) foi estudado. PLA HMW e PLA LMW foram caracterizadas por espectroscopia de infravermelho com transformada de Fourier (FTIR), análise termogravimétrica (TGA), calorimetria diferencial de varredura de temperatura modulada (MTDSC) e cromatografia de permeação de gel (GPC). A distribuição do tamanho das partículas e potencial-ζ das dispersões obtidas foram medidas por espalhamento de luz dinâmico (DLS) e espectroscopia eletroacústica, respectivamente. A adsorção de ovalbumina em nanopartículas foi avaliada pelo método de Bradford. A dispersão de PLA LMW mostrou menores valores de potencial-ζ e tamanhos maiores comparados à dispersão de PLA HMW . Uma menor adsorção de OVA foi alcançada por PLA LMW .
International Journal of Pharmaceutics, 2010
In order to evaluate the solubility effect of grafted moiety on the physicochemical properties of poly(d,llactide) (PLA) based nanoparticles (NPs), two materials of completely different aqueous solubility, polyethylene glycol (PEG) and palmitic acid were grafted on PLA backbone at nearly the same grafting density, 2.5% (mol of grafted moiety/mol of lactic acid monomer). Blank and ibuprofen-loaded NPs were fabricated from both polymers and their properties were compared to PLA homopolymer NPs as a control. NPs were analyzed for major physicochemical parameters such as encapsulation efficiency, size and size distribution, surface charge, thermal properties, surface chemistry, % poly(vinyl alcohol) (PVA) adsorbed at the surface of NPs, and drug release pattern. Encapsulation efficiency of ibuprofen was found to be nearly the same for both polymers ∼36% and 39% for PEG2.5%-g-PLA and palmitic acid2.5%-g-PLA NPs, respectively. Lyophilized NPs of palmitic acid2.5%-g-PLA either blank or loaded showed larger hydrodynamic diameter (∼180 nm) than PEG2.5%-g-PLA NPs (∼135 nm). PEG2.5%-g-PLA NPs showed lower % of PVA adsorbed at their surface (∼5%, w/w) than palmitic acid2.5%-g-PLA NPs (∼10%, w/w). Surface charge of palmitic acid2.5%-g-PLA NPs seems to be influenced by the large amount of PVA remains associated within their matrix. Thermal analysis using DSC revealed possible drug crystallization inside NPs. Both AFM phase imaging and XPS studies revealed the tendency of PEG chains to migrate towards the surface of PEG2.5%-g-PLA NPs. While, XPS analysis of palmitic acid2.5%-g-PLA NPs showed the tendency of palmitate chains to position themselves into the inner core of the forming particle avoiding facing the aqueous phase during NPs preparation using O/W emulsion method. The in vitro release pattern showed that PEG2.5%-g-PLA NPs exhibited faster release rates than palmitic acid2.5%-g-PLA NPs. PEG and palmitate chains when grafted onto PLA backbone, different modes of chain organization during NPs formation were obtained, affecting the physicochemical properties of the obtained NPs. The obtained results suggest that the properties of PLA-based NPs can be tuned by judicious selection of both chemistry and solubility profile of grafted material over PLA backbone.