Amphiphilic Core−Shell Nanoparticles with Poly(ethylenimine) Shells as Potential Gene Delivery Carriers

Article · January 2005with16 Reads
DOI: 10.1021/bc049895l · Source: PubMed
Abstract
Spherical, well-defined core-shell nanoparticles that consist of poly(methyl methacrylate) (PMMA) cores and branched poly(ethylenimine) shells (PEI) were synthesized via a graft copolymerization of methyl methacrylate from branched PEI induced by a small amount of tert-butyl hydroperoxide. The PMMA-PEI core-shell nanoparticles were between 130 to170 nm in diameter and displayed zeta-potentials near +40 mV at pH 7 in 1 mM aqueous NaCl. Plasmid DNA (pDNA) was mixed with nanoparticles and formed complexes of approximately 120 nm in diameter and was highly monodispersed. The complexes were characterized with respect to their particle size, zeta-potential, surface morphology, and DNA integrity. The complexing ability of the nanoparticles was strongly dependent on the molecular weight of the PEI and the thickness of the PEI shells. The stability of the complexes was influenced by the loading ratio of the pDNA and the nanoparticles. The condensed pDNA in the complexes was significantly protected from enzymatic degradation by DNase I. Cytotoxity studies using MTT colorimetric assays suggested that the PMMA-PEI (25 kDa) core-shell nanoparticles were three times less toxic than the branched PEI (25 kDa). Their transfection efficiencies were also significantly higher. Thus, the PEI-based core-shell nanoparticles show considerable potential as carriers for gene delivery.
    • Both PAMAM and PPI are cytotoxic in vitro which is due to their positive surface charge (Agashe et al., 2006; Kitchens et al., 2007). In the presence of linkers such as glycine, spermidine and bromoacetic acid, most of the surface primary amines were reacted thereby reducing the density of cationic residues leading to cell viability enhancement (Choksakulnimitr et al., 1995; Fischer et al., 1999; Putnam et al., 2001; Zhu et al., 2005). Several studies have indicated high gene transfection activity by high molecular weight polymers and high generation of dendrimers.
    [Show abstract] [Hide abstract] ABSTRACT: Nanomedicine as the interface between nanotechnology and medical sciences is a new area that has attracted the attention of vast groups of researchers. Carbon nanomaterials are common platform for synthesis of nanoparticles for biomedical applications due to their low cytotoxicity and feasible internalization into mammalian cell lines (Yang et al., 2007; Arora et al., 2014; Oh and Park, 2014). Synthesis of vectors based on various cationic polymers polyethylenimine (PEI), polypropylenimine (PPI) and polyamidoamine (PAMAM) and their derivatives were considered as a strategy for transferring plasmid DNA and treatment of genetic diseases. Considering the low cytotoxicity of graphene, chemical modification of its surface has led to fabrication of novel gene delivery systems based on graphene and graphene oxide. Herein we report the synthesis of three groups of vectors based on conjugation of graphene oxide (GO) with alkylated derivatives of three different cationic polymers (polyethylenimine (PEI), polypropylenimine (PPI) and polyamidoamine (PAMAM)) through different linkers including surface carboxyl group, glycine and spermidine. Two main challenges in design of gene delivery vectors is decreasing cytotoxicity while improving the transfection efficiency. All synthesized vectors showed significantly lower cellular toxicity compared to bare polymer. A plasmid encoding green fluorescent protein (GFP) was used to evaluate the transfection efficiency of nanoparticles both qualitatively using live cell fluorescent imaging and quantitatively using flow cytometry and each vector was compared to its polymer base. Most successful conjugation strategy was observed in the case of PEI conjugates among which most efficient vector was PEI-GO conjugate bearing glycine linker. This vector was 9 fold more effective in terms of the percent of EGFP transfected cells.
    Article · Apr 2016
    • PEI is quite often used as a control to evaluate the gene expression of other non-viral vectors, because it gives higher gene transfer efficiency. Cytotoxicity studies as shown by MTT and bioluminescence assays, coupled with the primary objective of enhancing transfection efficiency has led to experiments by grafting PEI with other polymers such as chito- san [236], polyglycerol [237], α, β–poly(L-aspartate-graft-PEI) [238], hyperbranched polyglycerol [239] and polymethylate/PEI core/shell NPs [235]. Along with PEI, poly(ethylene–glycol) (PEG) has also been used in conjugation with poly(γ-benzyl-L-glutamate) PEG/PBLG core/shell NP [240] and transfer in (Tf)-PEG-modified liposome [241] for the purpose of gene therapy.
    [Show abstract] [Hide abstract] ABSTRACT: Nanoparticles have several exciting applications in different areas and biomedial field is not an exception of that because of their exciting performance in bio-imaging, targeted drug and gene delivery, sensors, and so on. It has been found that among several classes of nanoparticles core/shell is most promising for different biomedical applications because of several advantages over simple nanoparticles. This review highlights the development of core/shell nanoparticles-based biomedical research during approximately past two decades. Applications of different types of core/shell nanoparticles are classified interms of five major aspects such as bioimaging, biosensor, targated drug delivery, DNA/RNA interaction, and targeted gene delivery.
    Article · Dec 2013
    • An efficient gene delivery system must be able to protect DNA from degradation by nucleases in serum and in the extracellular matrix.35 As shown in Figure 6, after incubation with DNase I, the naked DNA and the DNA in PEI 800-DNA complexes were all completely degraded, while the DNA in SP-DNA complexes or PEI 25,000-DNA complexes remained intact, indicating that both SP-DNA complexes and PEI 25,000-DNA complexes can effectively protect DNA from degradation by DNase I. Quantification of the intact DNA (ImageJ, NIH) revealed that 93.0% and 94.4% of the loaded DNA was recovered from the SP-DNA complexes and PEI 25,000-DNA complexes, respectively, indicating that the ability of SP to protect DNA from enzymatic cleavage is comparable with that of PEI 25,000.
    [Show abstract] [Hide abstract] ABSTRACT: A new amphiphilic comb-shaped copolymer (SP) was synthesized by conjugating poly(styrene-co-maleic anhydride) with low molecular weight polyethyleneimine for gene delivery. Fourier transform infrared spectrum, (1)H nuclear magnetic resonance, and gel permeation chromatography were used to characterize the graft copolymer. The buffering capability of SP was similar to that of polyethyleneimine within the endosomal pH range. The copolymer could condense DNA effectively to form complexes with a positive charge (13-30 mV) and a small particle size (130-200 nm) at N/P ratios between 5 and 20, and protect DNA from degradation by DNase I. In addition, SP showed much lower cytotoxicity than polyethyleneimine 25,000. Importantly, the gene transfection activity and cellular uptake of SP-DNA complexes were all markedly higher than that of complexes of polyethyleneimine 25,000 and DNA in MCF-7 and MCF-7/ADR cell lines. This work highlights the promise of SP as a safe and efficient synthetic vector for DNA delivery.
    Full-text · Article · Sep 2012
    • Involvement of nanotechnology currently has not only signifi cantly enhanced the effi cacy of polyethyleneiminebased siRNA delivery system but also substantially reduced its toxicity. For example, amphiphilic polyethyleneiminebased core-shell nanoparticles of 120 nm size show considerable potential as carriers for gene delivery [73] . As a result, the cytotoxicity of polyethyleneimine was found to be much reduced.
    [Show abstract] [Hide abstract] ABSTRACT: Rapid developments in the fi eld of nanotechnology are gener-ating enormous interest in prospecting the potential of multi-functional therapeutic nanovectors in the fi eld of personalized medicine. Although the nanomaterials are of same dimensions to many cellular machineries, their interaction with cells, tis-sues and organs of the body are not well understood. This in turn forms the rationale for a comprehensive study of these nanoplatforms in various disease models in terms of their tox-icity, pharmacokinetics, pharmacodynamics, and pharmaco-genetics. Such a study will signifi cantly aid in our quest in translating its application from bench to bedside.
    Full-text · Article · Jun 2012
    • Polyethyleneimine (PEI) is an efficient gene carrier, that has a proton-sponge effect (Boussif et al., 1995). PEI solubilizes QDs to water so it is also useful for surface coating of QDs (Duan et al., 2007, Zhu et al., 2005). CdSe/CdZnS QD cores that emit 605 nm fluorescence were synthesized (Jin et al., 2010) and PEI (average molecular weight about 10000) was added and heated to 60C in tetrahydrofuran.
    Full-text · Chapter · Aug 2011 · Journal of Controlled Release
    • To be efficient gene delivery system, the carriers must be able to protect DNA from degradation by cellular nucleases like DNase I abundant in serum and extracellular matrix [34,35]. Effective condensation is an important strategy for enhancing DNA stability against degradation by nucleases [36].
    [Show abstract] [Hide abstract] ABSTRACT: The efficient delivery of therapeutic gene into cells of interest is a critical challenge to broad application of non-viral vectors. The approach of introducing ligands that lead gene vectors to target caveolae-mediated endocytosis on nanoparticle surface might serve as a promising strategy for the effective gene transfection. Recently, in an attempt to enhance the possibility of caveolae-mediated endocytosis, we fabricated a peptide-targeted gene vector for highly efficient receptor-mediated intracellular delivery. Cyclic Asn-Gly-Arg (cNGR) peptide was used to target gene loaded poly(lactic acid)-poly(ethylene glycol) nanoparticles (PLA-PEG NPs) to HUVEC over-expressing CD13. Using 6-lauroxyhexyl lysinate (LHLN) as cationic surfactant, cNGR modified PLA-PEG NPs (cNGR-PEG-PLA NPs) were capable of complexing and compacting DNA into homogeneous small-sized complexes (<200nm) with positive charge (~10mV). Fortunately, the results of in vitro cellular uptake tests and mechanism studies were consistent with our original hypothesis. The cNGR peptide presented on nanoparticles' surface could specifically mediate the fast and efficient internalization of cNGR-PEG-PLA NPs into HUVEC. Moreover, free cNGR inhibited their intracellular uptake into HUVEC revealing the mechanism of receptor-mediated endocytosis. Furthermore, the inspiring results of the mechanism studies and transfection assays demonstrated that caveolae-mediated endocytosis was indeed mainly involved in the internalization of cNGR-PEG-PLA NPs into HUVEC and led to significant gene transfection efficiency in contrast with cNGR non-modified PLA-PEG NPs. Given such encouraging and favorable properties including biocompatibility, high transfer efficiency, low cytotoxicity, and fast uptake by nondestructive endocytic pathways, cNGR-PEG-PLA NPs could be a promising carrier for the intracellular delivery of therapeutic agents.
    Article · Mar 2011
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