Enhanced transfection with silica-coated polyplexes loading plasmid DNA

Thermally Robust Solvent-Free Liquid Polyplexes for Heat-Shock Protection and Long-Term Room Temperature Storage of Therapeutic Nucleic Acids

Nucleic acid therapeutics have attracted recent attention as promising preventative solutions for a broad range of diseases. Nonviral delivery vectors, such as cationic polymers, improve the cellular uptake of nucleic acids without suffering the drawbacks of viral delivery vectors. However, these delivery systems are faced with a major challenge for worldwide deployment, as their poor thermal stability elicits the need for cold chain transportation. Here, we demonstrate a biomaterial strategy to drastically improve the thermal stability of DNA polyplexes. Importantly, we demonstrate long-term room temperature storage with a transfection efficiency maintained for at least 9 months. Additionally, extreme heat shock studies show retained luciferase expression after heat treatment at 70 °C. We therefore provide a proof of concept for a platform biotechnology that could provide long-term room temperature storage for temperature-sensitive nucleic acid therapeutics, eliminating the need for the cold chain, which in turn would reduce the cost of distributing life-saving therapeutics worldwide.

Bioinspired Silicification of mRNA-Loaded Polyion Complexes for Macrophage-Targeted mRNA Delivery

In vitro transcribed messenger RNA (mRNA) delivery to macrophages is a promising therapeutic modality for inflammatory diseases because it can modulate the immunological activity of macrophages. However, efficient macrophage-targeted mRNA delivery remains challenging. Herein, we fabricated silica-coated polyion complexes (PICs), termed SilPICs, via bioinspired silicification for stable encapsulation of mRNA and scavenger receptor (SR)-mediated macrophage targeting. Silica coating was readily performed by simply mixing mRNA-loaded PICs with tetramethyl orthosilicate in aqueous media at 25 °C. The silica shell formation was verified by a slight increase in size (∼18 nm), a conversion of ζ-potential from positive (+22 mV) to negative (-23 mV), the peak appearance derived from silanol groups and siloxane bonds in the IR spectra, and elemental analyses by scanning transmission electron microscopy-energy-dispersive X-ray spectrometry (STEM-EDS). The silica shell efficiently protected the mRNA payload from enzymatic degradation in a fetal bovine serum-containing medium. Meanwhile, the reversibility of the silica shell allowed mRNA release from SilPICs after silica dissolution into silicic acids under diluted conditions. Furthermore, SilPICs elicited 20-fold higher mRNA transfection efficiency in the macrophage cell line RAW264.7 compared to noncoated PICs, presumably due to the facilitated cellular internalization by the silica shell. These enhancements were compromised in the RAW264.7 cells incubated with dextran sulfate and poly(inosinic acid) as inhibitors of SR type A1 and were not observed in cultured CT26 colon cancer cells, which are SR-negative cells. Collectively, SilPIC is a promising mRNA delivery vehicle with both mRNA protectability and macrophage targetability.

Effect of Tumor Suppressor MiR-34a Loaded on ZSM-5 Nanozeolite in Hepatocellular Carcinoma: In Vitro and In Vivo Approach

BACKGROUND

MicroRNA modulation therapy has shown great promise to treat hepatocellular carcinoma (HCC), however Efficient tissue-specific and safe delivery remains a major challenge.

OBJECTIVE

We sought to develop an inorganic-organic hybrid vehicle for the systemic delivery of the tumor suppressor miR-34a, and to investigate the efficiency of the delivered miR-34a in the treatment of HCC in vitro and in vivo.

METHODS

In the present study, pEGP-miR cloning and expression vector, expressing miR-34a, was electrostatically bound to polyethyleneimine (PEI), and then loaded onto ZSM-5 zeolite nanoparticles (ZNP). Qualitative and quantitative assessment of the transfection efficiency of miR-34a construct in HepG2 cells was applied by GFP screening and qRT-PCR, respectively. The expression of miR-34a target genes was investigated by qRT-PCR in vitro and in vivo.

RESULTS

ZNP/PEI/miR-34a nano-formulation could efficiently deliver into HepG2 cells with low cytotoxicity, indicating good biocompatibility of generated nanozeolite. Furthermore, five injected doses of ZNP/PEI/miR-34a nano-formulation in HCC induced male Balb-c mice, significantly inhibited tumor growth, and demonstrated improved cell structure, in addition to a significant decrease in alphafetoprotein level and liver enzymes activities, as compared to the positive control group. Moreover, injected ZNP/PEI/miR-34a nano-formulation led to a noticeable decrease in the CD44 and c-Myc levels. Results also showed that ZNP/PEI/miR-34a nano-formulation inhibited several target oncogenes including AEG-1, and SOX-9, in vitro and in vivo.

CONCLUSION

Our results suggested that miR-34a is a powerful candidate in HCC treatment and that AEG-1 and SOX-9 are novel oncotargets of miR-34a in HCC. Results also demonstrated that our nano-formulation may serve as a candidate approach for miR-34a restoration for HCC therapy, and generally for safe gene delivery.

Mesoporous Silica Nanoparticles for Co-Delivery of Drugs and Nucleic Acids in Oncology: A Review

Mesoporous silica nanoparticles have attracted much attention in recent years as drug and gene delivery systems for biomedical applications. Among their most beneficial features for biomedicine, we can highlight their biocompatibility and their outstanding textural properties, which provide a great loading capacity for many types of cargos. In the context of cancer nanomedicine, combination therapy and gene transfection/silencing have recently been highlighted as two of its most promising fields. In this review, we aim to provide an overview of the different small molecule drug-nucleic acid co-delivery combinations that have been developed using mesoporous silica nanoparticles as carriers. By carefully selecting the chemotherapeutic drug and nucleic acid cargos to be co-delivered by mesoporous silica nanoparticles, different therapeutic goals can be achieved by overcoming resistance mechanisms, combining different cytotoxic mechanisms, or providing an additional antiangiogenic effect. The examples here presented highlight the great promise of this type of strategies for the development of future therapeutics.

Methods of the Synthesis of Silicon-Containing Nanoparticles Intended for Nucleic Acid Delivery

A promising new approach to the treatment of viral infections and genetic diseases associated with damaged or foreign nucleic acids in the body is gene therapy, i.e., the use of antisense oligonucleotides, ribozymes, deoxyribozymes, siRNA, plasmid DNA, etc. (therapeutic nucleic acids). Selective recognition of target nucleic acids by these compounds based on highly specific complementary interaction can minimize negative side effects, which occur with currently used low molecular weight drugs. To apply a new generation of therapeutic agents in medical practice, it is necessary to solve the problem of their delivery into cells. Silicon-containing nanoparticles are considered as promising carriers for this purpose due to their biocompatibility, low toxicity, ability to biodegradation and excretion from the body, as well as the simplicity of the synthesis and modification. Silicon-containing nanoparticles are divided into two broad categories: solid (nonporous) and mesoporous silicon nanoparticles (MSN). This review gives a brief overview of the creation of mesoporous, multilayer, and other silicon-based nanoparticles. The publications concerning solid silicon-organic nanoparticles capable of binding and delivering nucleic acids into cells are discussed in more detail with emphasis on methods for their synthesis. The review covers publications over the past 15 years, which describe the classical Stöber method, the microemulsion method, modification of commercial silica nanoparticles, and other strategies.

Polymeric Amines and Ampholytes Derived from Poly(acryloyl chloride): Synthesis, Influence on Silicic Acid Condensation and Interaction with Nucleic Acid

Polymeric amines are intensively studied due to various valuable properties. This study describes the synthesis of new polymeric amines and ampholytes by the reaction of poly(acryloyl chloride) with trimethylene-based polyamines containing one secondary and several (1⁻3) tertiary amine groups. The polymers contain polyamine side chains and carboxylic groups when the polyamine was in deficiency. These polymers differ in structure of side groups, but they are identical in polymerization degree and polydispersity, which facilitates the study of composition-properties relationships. The structure of the obtained polymers was confirmed with ¹³C nuclear magnetic resonance infrared spectroscopy, and acid-base properties were studied with potentiometry titration. Placement of the amine groups in the side chains influences their acid-base properties: protonation of the amine group exerts a larger impact on the amine in the same side chain than on the amines in the neighboring side chains. The obtained polymers are prone to aggregation in aqueous solutions tending to insolubility at definite pH values in the case of polyampholytes. Silicic acid condensation in the presence of new polymers results in soluble composite nanoparticles and composite materials which consist of ordered submicrometer particles according to dynamic light scattering and electron microscopy. Polymeric amines, ampholytes, and composite nanoparticles are capable of interacting with oligonucleotides, giving rise to complexes that hold promise for gene delivery applications.

Silicic acid condensation under the influence of water-soluble polymers: from biology to new materials

Silicic acid condensation under the influence of functional polymers is reviewed starting from biology to new materials.

Systemic delivery of messenger RNA for the treatment of pancreatic cancer using polyplex nanomicelles with a cholesterol moiety

Systemic delivery of messenger RNA (mRNA) is technically challenging because mRNA is highly susceptible to enzymatic degradation in the blood circulation. In this study, we used a nanomicelle-based platform, prepared from mRNA and poly(ethylene glycol) (PEG)-polycation block copolymers. A cholesterol (Chol) moiety was attached to the ω-terminus of the block copolymer to increase the stability of the nanomicelle by hydrophobic interaction. After in vitro screening, polyaspartamide with four aminoethylene repeats in its side chain (PAsp(TEP)) was selected as the cationic segment of the block copolymer, because it contributes to enhance nuclease resistance and high protein expression from the mRNA. After intravenous injection, PEG-PAsp(TEP)-Chol nanomicelles showed significantly enhanced blood retention of mRNA in comparison to nanomicelles without Chol. We used the nanomicelles for treating intractable pancreatic cancer in a subcutaneous inoculation mouse model through the delivery of mRNA encoding an anti-angiogenic protein (sFlt-1). PEG-PAsp(TEP)-Chol nanomicelles generated efficient protein expression from the delivered mRNA in tumor tissue, resulting in remarkable inhibition of the tumor growth, whereas nanomicelles without Chol failed to show a detectable therapeutic effect. In conclusion, the stabilized nanomicelle system led to the successful systemic delivery of mRNA in therapeutic application, holding great promise for the treatment of various diseases.

Evaluation of biocompatible alginate- and deferoxamine-coated ternary composites for magnetic resonance imaging and gene delivery into glioblastoma cells

BACKGROUND

This paper describes comparative studies in cytotoxicities, magnetic resonance imaging (MRI), and gene delivery into glioblastoma U87MG or U138MG cells with ternary composites that are consist of superparamagnetic iron oxide (SPIO) nanoparticles (NPs) (size: 8-10 nm) with different surface coatings, circular plasmid DNA (pDNA) (~4 kb) equipped with fluorescent/luminescent probe, and branched polyethylenimine (25 kDa, PDI 2.5).

METHODS

Three types of SPIO-NPs were used, including: (I) naked iron oxide NPs with Fe-OH surface group (Bare-NP); (II) iron oxide NPs with a coating of alginate (Alg-NPs); and (III) iron oxide NPs with a coating of deferoxamine (Def-NPs). By tuning the polyethylenimine (PEI)/NP ratios and with a fixed DNA amount, different ternary composites were employed for NP/gene transfection into glioblastoma U87MG or U138MG cells, which were then characterized by Prussian blue staining, in vitro MRI, green fluorescence protein (GFP) fluorescence and luciferase assay.

RESULTS

Among the composites prepared, 0.2 ng PEI/0.5 µg DNA/1.0 µg Bare-NP ternary composite possessed the best cellular uptake efficiency of NP to the cytoplasm, following the trend Bare-NP > Alg-NP > Def-NP. This observation was consistent to the MRI assessments with in vitro T 2 relaxivity (r 2) values of 46.0, 35.5, and 23.7 s(-1)·µM(-1)·Fe, respectively. For cellular uptake efficiency of the pDNA, all variations of PEI/NP ratios of the composites did not yield significant differences. However, cellular uptake efficiencies of pDNA in the ternary composites in U138MG cells were generally higher than that of U87MG cells by an order of magnitude. Exceptionally, the ternary composite 0.2 ng PEI/0.5 µg DNA/1.0 µg Bare-NP possessed a lowered luciferase activity RLU for gene expression in U138MG cells. A total of 0.2 ng PEI/0.5 µg DNA/0.1 µg Bare-NP would be uptaken to the cell nucleus with the highest luciferase activity. A working concentration range of PEI with at least 15% higher cell viabilities than lipofectamine was 0.1 to 0.2 ng/well. The cytotoxicities became significant when 0.5 ng/well PEI was present in the ternary composites.

CONCLUSIONS

The as-prepared composites offer potential biomedical applications in simultaneous gene delivery, imaging contrast enhancement, and metabolism study.

Multilayered Nanoparticles for Gene Delivery Used to Reprogram Human Foreskin Fibroblasts to Neurospheres

Polycationic nanocomplexes are a robust means for achieving nucleic acid condensation and efficient intracellular gene deliveries. To enhance delivery, a multilayered nanoparticle consisting of a core of electrostatically bound elements was used. These included a histone-mimetic peptides, poly-l-arginine and poly-d-glutamic acid was coated with silicate before surface functionalization with poly-l-arginine. Transfection efficiencies and duration of expression were similar when using green fluorescent protein (GFP) plasmid DNA (pDNA) or GFP mRNA. These nanoparticles demonstrated significantly higher (>100%) and significantly longer (15 vs. 4 days) transfection efficiencies in comparison to a commercial transfection agent (Lipofectamine 2000). Reprogramming of human foreskin fibroblasts using mRNA to the Sox2 transcription factor resulted in three-fold higher neurosphere formation in comparison to the commercial reagent. These results demonstrate the potential of these nanoparticles as ideal vectors for gene delivery.

Smart drug delivery systems: from fundamentals to the clinic

Smart materials can endow implantable depots, targetable nanocarriers and insertable medical devices with activation-modulated and feedback-regulated control of drug release.

Ternary hybrid nanocomposites for gene delivery and magnetic resonance imaging of hepatocellular carcinoma cells

This paper describes comparative studies in magnetic resonance imaging (MRI) and gene deliveries toward hepatocellular carcinoma (HCC) HepG2 cells with ternary composites that consist of superparamagnetic iron oxide (SPIO) nanoparticles (NPs) (8-10 nm) with deferoxamine coating, circular plasmid DNA (~4 kb) equipped with green fluorescent probe, and branched polyethylenimine (PEI) (25 kDa, PDI 2.5). The packaging of the ternary complexes has been characterized by agarose gel retardation assay. By tuning the PEI/NP ratios and with a fixed DNA amount, different ternary composites have been employed for NP/gene transfection towards HepG2 cells, which have been characterized by in vitro MRI and green fluorescence protein (GFP) fluorescence.

Nanoparticle-DNA-polymer composites for hepatocellular carcinoma cell labeling, sensing, and magnetic resonance imaging

This paper describes comparative studies and protocols in (1) self-assembling of ultrasmall superparamagnetic iron oxide nanoparticle (NP), circular plasmid DNA, and branched polyethylenimine (PEI) composites; (2) magnetofection; (3) gene delivery, (4) magnetic resonance imaging (MRI), and (5) cytotoxicity of the composites toward hepatocellular carcinoma HepG2 cells.

Nonporous Silica Nanoparticles for Nanomedicine Application

Nanomedicine, the use of nanotechnology for biomedical applications, has potential to change the landscape of the diagnosis and therapy of many diseases. In the past several decades, the advancement in nanotechnology and material science has resulted in a large number of organic and inorganic nanomedicine platforms. Silica nanoparticles (NPs), which exhibit many unique properties, offer a promising drug delivery platform to realize the potential of nanomedicine. Mesoporous silica NPs have been extensively reviewed previously. Here we review the current state of the development and application of nonporous silica NPs for drug delivery and molecular imaging.

Polymer gene delivery vectors encapsulated in thermally sensitive bioreducible shell

Stable, nanosized polyelectrolyte complexes between rationally designed thermally sensitive block copolymers and plasmid DNA (polyplexes) were formed and their in vitro transfection efficiency was tested. The polyplexes were further stabilized through encapsulation into a biodegradable polymer shell. Although reduced as compared to that of the corresponding polyplexes, the encapsulated systems still show acceptable transfection efficiency. That opens the possibility to tune the balance between the safe transport and efficient delivery of DNA into the cells.

A calcium phosphate nanoparticle-based biocarrier for efficient cellular delivery of antisense oligodeoxynucleotides

Antisense oligodeoxynucleotides (ASODNs) can bind to some specific RNA of survivin can prevent the mRNA translation at the genetic level, which will inhibit survivin expression and make the cancer cells apoptosis. However, the ASODNs-based therapies are hampered by their instability to cellular nuclease and their weak intracellular penetration. Here we reported a calcium phosphate (CP)-based carrier to achieve efficient delivery of ASODNs into cells. In this study, we used a facile microemulsion approach to prepare spherical and porous ASODNs-CP nanoparticles (ASODNS-CPNPs) with the size of 50-70 nm in diameter, and their structure, morphology and composition were characterized by TEM, XRD, FTIR, ICP and DLS, UV-Vis spectroscopy and agarose gel electrophoresis. The results indicated that the nanoparticles have a high ASODNs loading capacity. Furthermore, cellular uptake and delivery efficiency of the ASODNS-CPNPs, as well as cellular apoptosis induced by the ASODNs doping into the calcium phosphate nanoparticles, were investigated by confocal laser scanning microscopy, biological TEM, flow cytometry, and MTT assay. Efficient intracellular delivery of the nanoparticles was observed. All these results suggested that the prepared calcium phosphate nanoparticles could be used as a promising biocarrier for delivery of ASODNs.

Recent advances in the rational design of silica-based nanoparticles for gene therapy

Gene therapy has attracted much attention in modern society and provides a promising approach for treating genetic disorders, diseases and cancers. Safe and effective vectors are vital tools to deliver genetic molecules to cells. This review summarizes recent advances in the rational design of silica-based nanoparticles and their applications in gene therapy. An overview of different types of genetic agents available for gene therapy is provided. The engineering of various silica nanoparticles is described, which can be used as versatile complexation tools for genetic agents and advanced gene therapy. Several challenges are raised and future research directions in the area of gene therapy using silica-based nanoparticles are proposed.

Smart multilayered assembly for biocompatible siRNA delivery featuring dissolvable silica, endosome-disrupting polycation, and detachable PEG

Multifunctional delivery systems of small interfering RNA (siRNA) are needed to overcome the intrinsic biological barriers toward efficient gene silencing in the cell cytoplasm. In this report, a smart multilayered assembly (SMA) was fabricated by a layer-by-layer method with polyionic materials. The SMA was designed to feature a siRNA-loaded core, a transiently core-stabilizing silica interlayer, an endosome-disrupting polycation interlayer, and a biocompatible poly(ethylene glycol) (PEG) shell with reductive environment-responsive detachability. The SMA was confirmed to be approximately 160 nm in size with narrow distribution and spherical morphology by DLS and TEM analyses. The PEG detachability of the SMA based on disulfide cleavage was also confirmed by the increase in both ζ-potential and size due to the exposure of the polycation interlayer and the compromised colloidal stability. The silica interlayer rendered the SMA highly tolerant to dissociation induced by anionic lipids, while after 24 h dialysis siRNA release from the SMA was clearly observed, presumably due to gradual dissolution of the silica interlayer based on the equilibrium shift to silicate ions. The entrapment ratio of siRNA delivered by the SMA within the endosome was significantly lower than that by nondisulfide control (NDC) without PEG detachability, suggesting the improved endosomal escape of SMA with the exposed, endosome-disrupting interlayer after PEG detachment. SMAs induced significantly higher gene silencing efficiency in various cultured cells, compared to NDC, without associated cytotoxicity. The systemic administration of SMAs for subcutaneous tumor-bearing mice achieved significant endogenous gene silencing in tumor tissue without hematological toxicity.