Spongelike alginate nanoparticles as a new potential system for the delivery of antisense oligonucleotides.

The aim of this study was to design a new antisense oligonucleotide (ON) carrier system based on alginate nanoparticles and to investigate its ability to protect ON from degradation in the presence of serum. Pharmacokinetics and tissue distribution of ON-loaded nanoparticles have been determined after intravenous administration. An original and dynamic process for ON loading into polymeric nanoparticles has been applied. It is based on the diffusion of ON or ON/polylysine complex into the nanoparticle or the alginate gel, respectively. Indeed, the single coincubation of ON with nanoparticles led, within a few days, to an extremely efficient association. The diffusion kinetic of ON was shown to be dependent on several parameters, incubation temperature, ON concentration, presence or absence of polylysine, polylysine molecular weight, and nanoparticle preparation procedure. This new alginate-based system was found to be able to protect [33P]-radiolabeled ON from degradation in bovine serum medium and to modify their biodistribution, as an important accumulation of radioactivity was observed in the lungs, in the liver, and in the spleen after intravenous administration into mice. ON may be associated efficiently with calcium alginate in a colloidal state. Such nanosponges are promising carriers for specific delivery of ON to lungs, liver, and spleen.     

Cellular fate of a modular DNA delivery system mediated by silica nanoparticles

Development of efficient molecular medicines, including gene therapeutics, RNA therapeutics, and DNA vaccines, depends on efficient means of transfer of DNA or RNA into the cell. Potential problems, including toxicity and immunogenicity, surrounding viral methods of DNA delivery have necessitated the use of nonviral, synthetic carriers. To better design synthetic carriers, or transfection reagents, the modular design of viruses has inspired a modular approach to DNA and RNA delivery. Each modular component can be designed to circumvent each of the many barriers. The modular approach will allow modification of individual components for a specific application. By utilizing a dense silica nanoparticle to form a ternary complex, transfection efficiency of a DNA-transfection reagent complex was increased by a factor of approximately 10 by concentrating the DNA at the surface of cells. Surface modification of the silica nanoparticles allowed determination of the cellular uptake mechanism with only minor alteration of transfection efficiency. Nanoparticles are internalized by an endosome-lysosomal route followed by perinuclear accumulation. The modification mechanism confirms that surface modification of the modular system can allow specific moieties to be incorporated into the modular system without significant alteration of the transfection efficiency. By showing that the modular system based upon concentration of DNA at the level of the cell can be used to increase transfection efficiency, we have shown that further modification of the system may better target DNA delivery and overcome other barriers of DNA expression.     

层层自组装纳米粒作为非病毒基因载体

基因治疗的效果严重依赖于基因载体。与传统包封技术相比,在自组装技术基础上发展起来的以DNA为聚阴离子,与荷正电的高分子材料在溶液中形成纳米粒的方法,已成为目前最重要的非病毒基因载体制备手段,具有良好的应用前景。采用层层自组装(layer-by-layer assembly,LbL)技术可提高基因装载率,其优势还在于纳米粒表面性质的可控性:在温和的条件下实现多种材料在载体表面的固定,实现载体多功能化等。本文将对近年来国内外有关层层自组装纳米粒作为非病毒基因载体的研究进展以及本课题组在此方向的研究进行简要综述。     

Layered double hydroxide nanoparticles as cellular delivery vectors of supercoiled plasmid DNA

We prepared stable homogeneous suspensions with layered double hydroxide (LDH) nanoparticles for in vitro gene delivery tests. The viability of HEK 293T cells in the presence of LDH nanoparticles at different concentrations was investigated. This revealed 50% cell viability at 500 microg/mL of LDH nanoparticles that is much higher than 50-100 microg/mL used for the delivery tests. The supercoiled pEF-eGFP plasmid (ca. 6100 base pairs) was mixed with LDH nanoparticle suspensions for anion exchange at a weight ratio of DNA/LDH between 1:25 and 1:100. In vitro experiments show that GFP expression in HEK 293T cells starts in the first day, reaches the maximum levels by the second day and continues in the third day. The GFP expression generally increases with the increase in DNA loading in DNA-LDH nanohybrids. However, the delivery efficiency with LDH nanoparticles as the agent is low. For example, the relative efficiency is 7%-15% of that of the commercial agent FuGENE 6. Three to 6% of total cells expressed GFP in an amount detectable by the FACS cytometry 2 days after transfection at 1 microg/mL of plasmid DNA with 25 microg/mL of LDH nanomaterial. The lower delivery efficiency could be attributed to the aggregation of LDH nanoparticles caused by the long-chain plasmid DNA.     

脂质体药物传递系统

脂质体已经发展成为一种成熟的传递系统,从脂质体作为载体概念的提出发展到生产制药水平历经了很长的发展阶段,如今脂质体制剂已有效地应用于重要疾病的治疗领域。简述了有关药物传递脂质体的目标和系统,透视了那些正在研究的领域,以及有哪些机会可合理改进脂质体的药物治疗。     

Silicon nanoparticles as a luminescent label to DNA

We successfully conjugated 1-2 nm diameter silicon nanoparticles to a 5'-amino-modified oligonucleotide (60mer) that contains a C6 linker between amide and phosphate groups. The conjugation was implemented via two photoinduced reactions followed by a DNA labeling step through formation of a carboxamide bond. Photoluminescence of the conjugates is dominated by two blue bands (400 and 450 nm maximal) under 340 nm excitation. The quantum yield of oligonucleotide-conjugated nanoparticles was determined to be 0.08 as measured against quinine sulfate in 0.1 M HClO(4) as a reference standard. We report a conjugation process that allows labeling of Si nanoparticles to an oligonucleotide in aqueous solutions. Ways to further optimize the procedure in order to achieve narrower and brighter photoluminescence are discussed.     

DNA nanoparticles and development of DNA delivery vehicles for gene therapy

DNA transport through the cell membrane is an essential requirement for gene therapy, which utilizes oligonucleotides and plasmid DNA. However, membrane transport of DNA is an inefficient process, and the mechanism(s) by which this process occurs is not clear. Although viral vectors are effective in gene therapy, the immune response elicited by viral proteins poses a major problem. Therefore, several laboratories are involved in the development of nonviral DNA delivery vehicles. These vehicles include polyamines, polycationic lipids, and neutral polymers, capable of condensing DNA to nanoparticles with radii of 20-100 nm. Although the structural and energetic forces involved in DNA condensation have been studied by physical biochemists for the past 25 years, this area has experienced a resurgence of interest in recent years because of the influx of biotechnologists involved in developing gene therapy protocols to combat a variety of human diseases. Despite an intense effort to study the mechanism(s) of DNA condensation using a variety of microscopic, light scattering, fluorescence, and calorimetric techniques, the precise details of the energetics of DNA nanoparticle formation and their packing assembly are not known at present. Future studies aimed at defining the mechanism(s) of DNA compaction and structural features of DNA nanoparticles might aid in the development of novel gene delivery vehicles.     

Evaluation of alginate compressed matrices as prolonged drug delivery systems

This research investigated the use of sodium alginate for the preparation of hydrophylic matrix tablets intended for prolonged drug release using ketoprofen as a model drug. The matrix tablets were prepared by direct compression using sodium alginate, calcium gluconate, and hydroxypropylmethylcellulose (HPMC) in different combinations and ratios. In vitro release tests and erosion studies of the matrix tablets were carried out in USP phosphate buffer (pH 7.4). Matrices consisting of sodium alginate alone or in combination with 10% and 20% of HPMC give a prolonged drug release at a fairly constant rate. Incorporation of different ratios of calcium gluconate leads to an enhancement of the release rate from the matrices and to the loss of the constant release rate of the drug. Only the matrices containing the highest quantity of HPMC (20%) maintained their capacity to release ketoprofen for a prolonged time.     

Engineered nanoparticles as precise drug delivery systems

With the remarkable development of nanotechnology in recent years, new drug delivery approaches based on the state-of-the-art nanotechnology have been receiving significant attention. Nanoparticles, an evolvement of nanotechnology, are increasingly considered as a potential candidate to carry therapeutic agents safely into a targeted compartment in an organ, particular tissue or cell. These particles are colloidal structures with a diameter smaller than 1,000 nm, and therefore can penetrate through diminutive capillaries into the cell's internal machinery. This innovative delivery technique might be a promising technology to meet the current challenges in drug delivery. When loaded with a gene or drug agent, nanoparticles can become nanopills, which can effectively treat problematical diseases such as cancer. This article summarizes different types of nanoparticles drug delivery systems under investigation and their prospective therapeutic applications. Also, this article presents a closer look at the advances, current challenges, and future direction of nanoparticles drug delivery systems.     

Formation of core/shell nanoparticles with a lipid core and their application as a drug delivery system

A novel preparation method for core/shell nanoparticles with a drug-loaded lipid core was designed and characterized. The lipid core is composed of lecithin and a drug, and the polymeric shell is composed of Pluronics (poly(ethylene oxide)-poly (propylene oxide)-poly(ethylene oxide) triblock copolymer, F-127). For the formation of stabilized core/shell nanoparticles, freeze-drying was performed in the presence of trehalose used as a cryoprotectant. Cryogenic transmittance electron microscopy (cryo-TEM), differential scanning calorimetry (DSC), and a particle size analyzer were used to observe the formation of the stabilized core/shell nanoparticles. For the application of the core/shell nanoparticles as a drug carrier, paclitaxel, a potent anticancer drug, was loaded into the core/shell nanoparticles, and the drug loading amount and the drug release pattern were observed.     

A unique and highly efficient non-viral DNA/siRNA delivery system based on PEI-bisepoxide nanoparticles

Delivery of DNA and siRNA into mammalian cells is a powerful technique in treating various diseases caused by single gene defects. Herein, we report a highly efficient delivery system using 1,4-butanediol diglycidyl ether (bisepoxide) crosslinked polyethylenimine (PEI) nanoparticles (PN). The nanoparticle/DNA complexes (nanoplexes) exibited approximately 2.5- to 5.0-fold gene transfer efficacy and decreased cytotoxicity in cultured cell lines, compared to the native PEI (25 kDa) (gold standard) and commercially available transfection agents such as Lipofectamine 2000 and Fugene. The bisepoxide crosslinking results in change in amine ratio in PEI; however, it retains the net charge on PN unaltered. A series of nanoparticles obtained by varying the degree of crosslinking was found to be in the size range of 69-77 nm and the zeta potential varying from +35 to 40 mV. The proposed system was also found to deliver siRNA efficiently into HEK cells, resulting in approximately 70% suppression of the targetted gene (GFP).     

红细胞伪装纳米颗粒:一个具有潜力的药物及疫苗递送系统

红细胞伪装纳米颗粒是一种以红细胞或红细胞膜纳米囊泡为载体在体内递送药物、酶、多肽和抗原等物质的系统,具有生物相容性好、循环周期长、靶向性强等优势。本文从红细胞载体的种类、发展历程、递送策略应用以及其局限性和未来的挑战等方面进行了详细阐述,并展望了其未来的发展方向。     

Bacteria-produced ferric exopolysaccharide nanoparticles as iron delivery system for truffles (Tuber borchii)

Applied Microbiology and Biotechnology - Iron exopolysaccharide nanoparticles were biogenerated during ferric citrate fermentation by Klebsiella oxytoca DSM 29614. Before investigating their...     

Synthesis and characterization of alginate coated zinc calcium phosphate nanoparticles for intestinal delivery of insulin

Nanosized calcium phosphates studied as drug delivery systems are highly compatible with the various drugs like insulin, antibiotics etc. Zinc is an essential trace element that plays a crucial role in the synthesis, storage and release of insulin in a human body. Therefore, an attempt has been made to develop zinc modified calcium phosphate nanoparticles (less than 100 nm) as carriers for intestinal delivery of insulin. The insulin loaded nanoparticles were coated with pH sensitive alginate. These pH sensitive nanoparticles released insulin in the intestinal medium, and the conformation of released insulin was stable. The blood glucose level of diabetic rats came to normal on administration of the formulation. With the beneficial effect of zinc reported on diabetic patients, the present system seems to be an excellent carrier for intestinal delivery of insulin.     

Peptide-based hydrogel nanoparticles as effective drug delivery agents

Peptide-based hydrogel nanoparticles represent a promising alternative to current drug delivery approaches. We have previously demonstrated that the Fmoc-FF aromatic dipeptide building block can self-assemble in aqueous solutions to form nano-scaled ordered hydrogels of remarkable mechanical rigidity. Here, we present a scalable process for the assembly of this peptide into hydrogel nanoparticles (HNPs) aimed to be utilized as potential drug delivery carriers. Fmoc-FF based HNPs were formulated via modified inverse-emulsion method using vitamin E-TPGS as an emulsion stabilizer and high speed homogenization. The formed HNPs exhibited two distinguishable populations with an average size of 21.5 ± 1.3 and 225.9 ± 0.8 nm. Gold nanoparticles were encapsulated within the hydrogel nanoparticles as contrast agents to monitor the formation of the assemblies and their ultrastructural properties. Next, we demonstrated a robust experimental procedure developed and optimized for the formulation, purification, storage and handling procedures of HNPs. Encapsulation of doxorubicin (Dox) and 5-flourouracil (5-Fu) within the HNPs matrix showed release kinetics of the drugs depending on their chemical structure, molecular weight and hydrophobicity. The results clearly indicate that Fmoc-FF based hydrogel nanoparticles have the potential to be used as encapsulation and delivery system of various drugs and bioactive molecules.     

无机纳米粒子作为基因载体的研究进展

转染是将具生物功能的核酸转移、运送到细胞内,并使其在细胞内维持生物功能的过程。作为现代生物化学和分子生物学中的一种主要技术手段,转染对于基因治疗有重要的意义。无机纳米粒子作为基因载体受到人们日益广泛的关注,其具有易于制备,可进行多样化的表面修饰等多种优势。本文将概述无机纳米粒子作为基因载体的现状及其对基因表达的影响。     

Fibrin nanoparticles as Possible vehicles for drug delivery

Background

Several issues have been raised emphasizing the harmful toxic effects of metal nanoparticles towards biological systems. Search of biological nanoparticles with excellent biocompatibility and bioavailability could address this problem.

Methods

Fibrin nanoparticles (FNP) were prepared using a novel technique and characterized for their physico-chemical properties. In vitro studies were performed to examine cytotoxicity and cellular uptake of FNP. Innate immune response to FNP was studied by (i) estimating in vitro generation of complement split products, C3a and C4d and (ii) in vivo expression of pro-inflammatory cytokines, TNF-α, IL-1 and IL-6. In vivo biodistribution study was carried out by intravenous administration of FITC-labelled FNP in mice.

Results

FNP were spherical with size ranging from 25 to 28 nm. In vitro studies proved the biocompatibility of the nanoparticles, with their distribution across the cytoplasm and nucleus of treated cells. Complement activation studies showed insignificant increase in the level of C3a when compared with positive control. RT-PCR results revealed significant upregulation of TNF-α and downregulation of IL-6 cytokines after 6 h of FNP administration. In vivo biodistribution studies showed moderate blood circulation time, with predominant distribution of nanoparticles in the liver followed by the lungs, kidney and spleen. Haematology, serum biochemistry, and histopathology analyses demonstrated that FNP were non-toxic.

Conclusion

Owing to their small size, low cost, ease of preparation and excellent biocompatibility, FNP might be a promising novel material for drug delivery applications.

General significance

Our results demonstrate the safe and promising use of FNP for biomedical applications.     

Bovine serum albumin/gold nanoparticles as a drug delivery system for Curcumin: experimental and computational studies

Abstract

Communicated by Ramaswamy H. Sarma     

Metallohelix vectors for efficient gene delivery via cationic DNA nanoparticles

The design of efficient and safe gene delivery vehicles remains a major challenge for the application of gene therapy. Of the many reported gene delivery systems, metal complexes with high affinity for nucleic acids are emerging as an attractive option. We have discovered that certain metallohelices—optically pure, self-assembling triple-stranded arrays of fully encapsulated Fe—act as nonviral DNA delivery vectors capable of mediating efficient gene transfection. They induce formation of globular DNA particles which protect the DNA from degradation by various restriction endonucleases, are of suitable size and electrostatic potential for efficient membrane transport and are successfully processed by cells. The activity is highly structure-dependent—compact and shorter metallohelix enantiomers are far less efficient than less compact and longer enantiomers.     

Effective delivery of anti-miRNA DNA oligonucleotides by functionalized gold nanoparticles

MicroRNAs (miRNAs) are gaining recognition as essential regulators involved in many biological processes, and they are emerging as therapeutic targets for treating disease. Here, we introduce a method for effective delivery of anti-miRNA oligonucleotides (AMOs) using functionalized gold nanoparticles (AuNPs). To demonstrate the ability of AMOs to silence miRNA, we selected miR-29b, which is known to downregulate myeloid cell leukemia-1 (MCL-1), a factor responsible for promoting cell survival. We first generated AuNPs coated with cargo DNA, which was then coupled to complementary DNA linked to an antisense miR-29b sequence. When the AuNPs were delivered into HeLa cells, MCL-1 protein and mRNA levels were increased significantly. Furthermore, apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was inhibited, proving that AMOs targeting miR-29b were effectively delivered by our innovative AuNP. In addition, we provided evidence that AuNP could deliver other AMOs against miR-21 into two independent cell lines, KGN and 293T, suggesting that the AuNP conjugates can be versatile for any AMO and cell type.