Sustained delivery and expression of DNA encapsulated in polymeric nanoparticles

Solid nano-in-nanoparticles for potential delivery of siRNA

siRNA-based therapeutics possess great potential to treat a wide variety of genetic disorders. However, they suffer from low cellular uptake and short half-lives in blood circulation; issues that remain to be addressed. This work is, to the best of our knowledge, the first to report the production of solid nano-in-nanoparticles, termed double nano carriers (DNCs) by means of the innovative technology of nano spray drying. DNCs (with a median size of 580-770nm) were produced by spraying at low temperatures (50°C) to prevent damage to heat-sensitive biomacromolecules like siRNA. DNCs consisting of Poly (d,l-lactide-co-glycolide) used as a wall material, encapsulating 20% human serum albumin primary nanoparticles (PNPs) loaded with siRNA, were obtained as a dry nanoparticulate powder with smooth spherical surfaces and a unique inner morphology. Incubation of pegylated or non-pegylated DNCs under sink conditions at 37°C, elicited a controlled release profile of the siRNA for up to 12 or 24h, respectively, with a minimal burst effect. Prolonged incubation of pegylated DNCs loaded with active siRNA (anti EGFR) in an A549 epithelial cell culture monolayer did not induce any apparent cytotoxicity. A slow degradation of the internalized DNCs by the cells was also observed resulting in the progressive release of the siRNA for up to 6days, as corroborated by laser confocal microscopy. The structural integrity and silencing activity of the double encapsulated siRNA were fully preserved, as demonstrated by HPLC, gel electrophoresis, and potent RNAi activity of siRNA extracted from DNCs. These results demonstrate the potential use of DNCs as a nano drug delivery system for systemic administration and controlled release of siRNA and potentially other sensitive bioactive macromolecules.

Study of the combined treatment of lung cancer using gene-loaded immunomagnetic albumin nanospheres in vitro and in vivo

Combination therapy for lung cancer has garnered widespread attention. Radiation therapy, gene therapy, and molecular targeted therapy for lung cancer have certain effects, but the disadvantages of these treatment methods are evident. Combining these methods can decrease their side effects and increase their curative effects. In this study, we constructed a pYr-ads-8-5HRE-cfosp-iNOS-IFNG plasmid (a gene circuit that can express IFNγ), which is a gene circuit, and used that plasmid together with C225 (cetuximab) to prepare gene-loaded immunomagnetic albumin nanospheres (IMANS). Moreover, we investigated the therapeutic effects of gene-loaded IMANS in combination with radiation therapy on human lung cancer in vitro and in vivo. The results showed that this gene circuit was successively constructed and confirmed that the expression of INFγ was increased due to the gene circuit. Gene-loaded IMANS combined with radiation therapy demonstrated improved results in vitro and in vivo. In conclusion, gene-loaded IMANS enhanced the efficacy of combination therapy, solved problems related to gene transfer, and specifically targeted lung cancer cells.

Therapeutic Use of 3β-[N-(N',N'-Dimethylaminoethane) Carbamoyl] Cholesterol-Modified PLGA Nanospheres as Gene Delivery Vehicles for Spinal Cord Injury

Gene delivery holds therapeutic promise for the treatment of neurological diseases and spinal cord injury. Although several studies have investigated the use of non-viral vectors, such as polyethylenimine (PEI), their clinical value is limited by their cytotoxicity. Recently, biodegradable poly (lactide-co-glycolide) (PLGA) nanospheres have been explored as non-viral vectors. Here, we show that modification of PLGA nanospheres with 3β-[N-(N′,N′-dimethylaminoethane) carbamoyl] cholesterol (DC-Chol) enhances gene transfection efficiency. PLGA/DC-Chol nanospheres encapsulating DNA were prepared using a double emulsion-solvent evaporation method. PLGA/DC-Chol nanospheres were less cytotoxic than PEI both in vitro and in vivo. DC-Chol modification improved the uptake of nanospheres, thereby increasing their transfection efficiency in mouse neural stem cells in vitro and rat spinal cord in vivo. Also, transgene expression induced by PLGA nanospheres was higher and longer-lasting than that induced by PEI. In a rat model of spinal cord injury, PLGA/DC-Chol nanospheres loaded with vascular endothelial growth factor gene increased angiogenesis at the injury site, improved tissue regeneration, and resulted in better recovery of locomotor function. These results suggest that DC-Chol-modified PLGA nanospheres could serve as therapeutic gene delivery vehicles for spinal cord injury.

Targeted polymeric nanoparticles for cancer gene therapy

In this article, advances in designing polymeric nanoparticles for targeted cancer gene therapy are reviewed. Characterization and evaluation of biomaterials, targeting ligands, and transcriptional elements are each discussed. Advances in biomaterials have driven improvements to nanoparticle stability and tissue targeting, conjugation of ligands to the surface of polymeric nanoparticles enable binding to specific cancer cells, and the design of transcriptional elements has enabled selective DNA expression specific to the cancer cells. Together, these features have improved the performance of polymeric nanoparticles as targeted non-viral gene delivery vectors to treat cancer. As polymeric nanoparticles can be designed to be biodegradable, non-toxic, and to have reduced immunogenicity and tumorigenicity compared to viral platforms, they have significant potential for clinical use. Results of polymeric gene therapy in clinical trials and future directions for the engineering of nanoparticle systems for targeted cancer gene therapy are also presented.

Current strategies for targeted delivery of bio-active drug molecules in the treatment of brain tumor

Brain tumor is one of the most challenging diseases to treat. The major obstacle in the specific drug delivery to brain is blood-brain barrier (BBB). Mostly available anti-cancer drugs are large hydrophobic molecules which have limited permeability via BBB. Therefore, it is clear that the protective barriers confining the passage of the foreign particles into the brain are the main impediment for the brain drug delivery. Hence, the major challenge in drug development and delivery for the neurological diseases is to design non-invasive nanocarrier systems that can assist controlled and targeted drug delivery to the specific regions of the brain. In this review article, our major focus to treat brain tumor by study numerous strategies includes intracerebral implants, BBB disruption, intraventricular infusion, convection-enhanced delivery, intra-arterial drug delivery, intrathecal drug delivery, injection, catheters, pumps, microdialysis, RNA interference, antisense therapy, gene therapy, monoclonal/cationic antibodies conjugate, endogenous transporters, lipophilic analogues, prodrugs, efflux transporters, direct conjugation of antitumor drugs, direct targeting of liposomes, nanoparticles, solid-lipid nanoparticles, polymeric micelles, dendrimers and albumin-based drug carriers.

Nanocarriers in therapy of infectious and inflammatory diseases

Nanotechnology is a growing science that has applications in various areas of medicine. The composition of nanocarriers for drug delivery is critical to guarantee high therapeutic performance when targeting specific host sites. Applications of nanotechnology are prevalent in the diagnosis and treatment of infectious and inflammatory diseases. This review summarizes recent advancements in the application of nanotechnology to the therapy of infectious and inflammatory diseases. The major focus is on the design and fabrication of various nanomaterials, characteristics and physicochemical properties of drug-loaded nanocarriers, and the use of these nanoscale drug delivery systems in treating infectious and inflammatory diseases, such as AIDS, hepatitis, tuberculosis, melanoma, and representative inflammatory diseases. Clinical trials and future perspective of the use of nanocarriers are also discussed in detail. We hope that such a review will be valuable to researchers who are exploring nanoscale drug delivery systems for the treatment of specific infectious and inflammatory diseases.

Synthesis and evaluation of the targeted binding of RGD-containing PEGylated-PEI/DNA polyplex micelles as radiotracers for a tumor-targeting imaging probe

Polyplex micelles with pEGFP and RGD-modified poly(ethylene glycol)-grafted polyethylenimine (E[c(RGDyK)]₂-PEG-g-PEI) and were labeled with ^99mTc for the in vivo study as proficient probes for molecular imaging.

Therapeutic face of RNAi: in vivo challenges

INTRODUCTION

RNA interference is a sequence-specific gene silencing phenomenon in which small interfering RNAs (siRNAs) can trigger gene transcriptional and post-transcriptional silencing. This phenomenon represents an emerging therapeutic approach for in vivo studies by efficient delivery of specific synthetic siRNAs against diseases. Therefore, simultaneous development of synthetic siRNAs along with novel delivery techniques is considered as novel and interesting therapeutic challenges.

AREAS COVERED

This review provides a basic explanation to siRNA signaling pathways and their therapeutic challenges. Here, we provide a comprehensive explanation to failed and successful trials and their in vivo challenges.

EXPERT OPINION

Specific, efficient and targeted delivery of siRNAs is the major concern for their in vivo administrations. Also, anatomical barriers, drug stability and availability, immunoreactivity and existence of various delivery routes, different genetic backgrounds are major clinical challenges. However, successful administration of siRNA-based drugs is expected during foreseeable features. But, their systemic applications will depend on strong targeted drug delivery strategies.

Influence of calcium hydroxide-loaded microcapsules on osteoprotegerin and receptor activator of nuclear factor kappa B ligand activity

INTRODUCTION

Calcium hydroxide (Ca[OH]2) microcapsules were synthesized to allow controlled release of Ca(OH)2. The aim of this study was to evaluate the influence of Ca(OH)2 microcapsules on osteoprotegerin (OPG) activity, receptor activator of nuclear factor kappa B ligand (RANKL) activity, and the OPG/RANKL ratio compared with pure Ca(OH)2 powder and Vitapex (Neo Dental Chemical Products Co Ltd, Tokyo, Japan).

METHODS

One formula of Ca(OH)2 microcapsules was evaluated, and pure Ca(OH)2 powder was used as a control. A commonly used Ca(OH)2 medication containing an oily vehicle (Vitapex) was also evaluated, and the in vitro release profile of Vitapex was studied. The human osteosarcoma cell line MG63 was used to evaluate the influence of Ca(OH)2 microcapsules, pure Ca(OH)2 powder, and Vitapex on OPG and RANKL activity. The relative messenger RNA (mRNA) expression of OPG and RANKL was determined by real-time polymerase chain reaction. The protein expression of OPG and RANKL in supernatants was measured using enzyme-linked immunosorbent assay.

RESULTS

Vitapex prolonged the release of Ca(OH)2 compared with pure Ca(OH)2 powder, and the release rate of Vitapex was faster than that of the microcapsules. The OPG/RANKL ratio in the microcapsules group was up-regulated at both the mRNA and protein levels compared with the negative control group and the pure Ca(OH)2 powder group. The ratio in the Vitapex group was lower than the microcapsule group both at the mRNA and protein levels.

CONCLUSIONS

Ca(OH)2 microcapsules increased the expression of OPG although they did not increase the expression of RANKL compared with pure Ca(OH)2 powder and Vitapex. This increase in expression led to an increase in the OPG/RANKL ratio and eventual inhibition of osteoclast activity.

Synthesis, characterization, and evaluation of poly (D,L-lactide-co-glycolide)-based nanoformulation of miRNA-150: potential implications for pancreatic cancer therapy

MicroRNAs are small (18–22 nucleotide long) noncoding RNAs that play important roles in biological processes through posttranscriptional regulation of gene expression. Their aberrant expression and functional significance are reported in several human malignancies, including pancreatic cancer. Recently, we identified miR-150 as a novel tumor suppressor microRNA in pancreatic cancer. Furthermore, expression of miR-150 was downregulated in the majority of tumor cases, suggesting that its restoration could serve as an effective approach for pancreatic cancer therapy. In the present study, we developed a nanoparticle-based miR-150 delivery system and tested its therapeutic efficacy in vitro. Using double emulsion solvent evaporation method, we developed a poly (D,L-lactide-co-glycolide) (PLGA)-based nanoformulation of miR-150 (miR-150-NF). Polyethyleneimine (a cationic polymer) was incorporated in PLGA matrix to increase the encapsulation of miR-150. Physical characterization of miR-150-NF demonstrated that these nanoparticles had high encapsulation efficiency (~78%) and exhibited sustained release profile. Treatment of pancreatic cancer cells with miR-150-NF led to efficient intracellular delivery of miR-150 mimics and caused significant downregulation of its target gene (MUC4) expression. Inhibition of MUC4 correlated with a concomitant decrease in the expression of its interacting partner, HER2, and repression of its downstream signaling. Furthermore, treatment of pancreatic cancer cells with miR-150-NF suppressed their growth, clonogenicity, motility, and invasion. Together, these findings suggest that PLGA-based nanoformulation could potentially serve as a safe and effective nanovector platform for miR-150 delivery to pancreatic tumor cells.

Nucleus-targeted drug delivery: theoretical optimization of nanoparticles decoration for enhanced intracellular active transport

A rational design for a nanoparticle is suggested, which will maximize its arrival efficiency from the plasma membrane to the nuclear surrounding. The design is based on grafting the particle surface with polymer spacers, each ending with a motor protein associating molecule, for example, nuclear localization signal peptide. It is theoretically shown that the spacer polymer molecular weight can be adjusted to significantly increase the effective particle processivity time. This should lead to appreciable enhancement of active transport of the nanocarrier, and consequently drug delivery, to the nucleus.

Strategies and hurdles using DNA vaccines to fish

DNA vaccinations against fish viral diseases as IHNV at commercial level in Canada against VHSV at experimental level are both success stories. DNA vaccination strategies against many other viral diseases have, however, not yet yielded sufficient results in terms of protection. There is an obvious need to combat many other viral diseases within aquaculture where inactivated vaccines fail. There are many explanations to why DNA vaccine strategies against other viral diseases fail to induce protective immune responses in fish. These obstacles include: 1) too low immunogenicity of the transgene, 2) too low expression of the transgene that is supposed to induce protection, 3) suboptimal immune responses, and 4) too high degradation rate of the delivered plasmid DNA. There are also uncertainties with regard distribution and degradation of DNA vaccines that may have implications for safety and regulatory requirements that need to be clarified. By combining plasmid DNA with different kind of adjuvants one can increase the immunogenicity of the transgene antigen – and perhaps increase the vaccine efficacy. By using molecular adjuvants with or without in combination with targeting assemblies one may expect different responses compared with naked DNA. This includes targeting of DNA vaccines to antigen presenting cells as a central factor in improving their potencies and efficacies by means of encapsulating the DNA vaccine in certain carriers systems that may increase transgene and MHC expression. This review will focus on DNA vaccine delivery, by the use of biodegradable PLGA particles as vehicles for plasmid DNA mainly in fish.

Strategies and hurdles using DNA vaccines to fish

DNA vaccinations against fish viral diseases as IHNV at commercial level in Canada against VHSV at experimental level are both success stories. DNA vaccination strategies against many other viral diseases have, however, not yet yielded sufficient results in terms of protection. There is an obvious need to combat many other viral diseases within aquaculture where inactivated vaccines fail. There are many explanations to why DNA vaccine strategies against other viral diseases fail to induce protective immune responses in fish. These obstacles include: 1) too low immunogenicity of the transgene, 2) too low expression of the transgene that is supposed to induce protection, 3) suboptimal immune responses, and 4) too high degradation rate of the delivered plasmid DNA. There are also uncertainties with regard distribution and degradation of DNA vaccines that may have implications for safety and regulatory requirements that need to be clarified. By combining plasmid DNA with different kind of adjuvants one can increase the immunogenicity of the transgene antigen - and perhaps increase the vaccine efficacy. By using molecular adjuvants with or without in combination with targeting assemblies one may expect different responses compared with naked DNA. This includes targeting of DNA vaccines to antigen presenting cells as a central factor in improving their potencies and efficacies by means of encapsulating the DNA vaccine in certain carriers systems that may increase transgene and MHC expression. This review will focus on DNA vaccine delivery, by the use of biodegradable PLGA particles as vehicles for plasmid DNA mainly in fish.

Stimuli-responsive polymers in gene delivery

Recent interest in clinical therapy has been directed to deliver nucleic acids (DNA, RNA or short-chain oligonucleotides) that alter gene expression within a specific cell population, thereby manipulating cellular processes and responses, which in turn stimulate immune responses or tissue regeneration, or blocks expression at the level of transcription or translation for treatment of several diseases. Both ex vivo and in vivo gene delivery can be achieved mostly by using a delivery system (vector). Viral vectors exhibit high gene expression, but also have very significant side effects. Mainly cationic polymeric systems are used as nonviral vectors, although usually with low levels of transfection. Through the use of stimuli-responsive polymers as novel vectors for gene delivery, two benefits can be obtained: high gene expression efficiency and more selective gene expression.

A novel approach to monitor intracellular degradation kinetics of poly(lactide-co-glycolide) nanoparticles by means of flow cytometry

The intracellular degradation of poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) is studied by means of flow cytometry (FACS). NPs are prepared with PLGA of two different ratios of the d,l-lactide and glycolide blocks: 85 : 15 and 65 : 35. PLGA molecules are labelled with rhodamine B. Flow cytometry is first used to follow the degradation of PLGA NPs in PBS over time by measuring the decrease in fluorescence per particle. The 85 : 15 PLGA NPs progressively degrade during the first 10 days and remain constant thereafter. The 65 : 35 PLGA NPs remain unaltered, showing no changes in fluorescence intensity. FACS data are confirmed by transmission electron microscopy and dynamic light scattering measurements. Intracellular degradation of 85 : 15 PLGA is measured by the increase in fluorescence intensity in the cell population with time due to the liberation of rhodamine B labelled PLGA molecules from NPs in the cell interior where rhodamine displays an increased quantum yield. The fluorescence intensity from 85 : 15 PLGA NPs increases up to 24 hours, remaining constant thereafter. No change in the fluorescence of 65 : 35 PLGA NPs is observed after 4 days. The intracellular behaviour of the PLGA NPs is also confirmed by confocal Raman microscopy.

Gene therapy and DNA delivery systems

Gene therapy is a promising new technique for treating many serious incurable diseases, such as cancer and genetic disorders. The main problem limiting the application of this strategy in vivo is the difficulty of transporting large, fragile and negatively charged molecules like DNA into the nucleus of the cell without degradation. The key to success of gene therapy is to create safe and efficient gene delivery vehicles. Ideally, the vehicle must be able to remain in the bloodstream for a long time and avoid uptake by the mononuclear phagocyte system, in order to ensure its arrival at the desired targets. Moreover, this carrier must also be able to transport the DNA efficiently into the cell cytoplasm, avoiding lysosomal degradation. Viral vehicles are the most commonly used carriers for delivering DNA and have long been used for their high efficiency. However, these vehicles can trigger dangerous immunological responses. Scientists need to find safer and cheaper alternatives. Consequently, the non-viral carriers are being prepared and developed until techniques for encapsulating DNA can be found. This review highlights gene therapy as a new promising technique used to treat many incurable diseases and the different strategies used to transfer DNA, taking into account that introducing DNA into the cell nucleus without degradation is essential for the success of this therapeutic technique.

Achieving micelle control through core crystallinity

We have designed a pathway for controlling the critical micelle concentration and micelle size of polyester-based systems. This was achieved by creating an array of different copolymers with semicrystalline or amorphous hydrophobic blocks. The hydrophobic block was constructed through ring-opening polymerization of ε-caprolactone, l-lactide, and ε-decalactone, either as homopolymers or random copolymers, using PEG as both the initiator and the hydrophilic block. Micelles formed with amorphous cores exhibited considerably higher critical micelle concentrations than those with semicrystalline cores. Micelles with amorphous cores also became larger in size with an increased molecular weight of the hydrophobic bock, in contrast to micelles with semicrystalline cores, which displayed the opposite behavior. Hence, core crystallinity was found to be a potent tool for tailoring micelle properties and thereby facilitating the optimization of drug delivery systems. The introduction of PEG-PεDL also proved to be a valuable asset in the tuning of micelle properties.

Synthesis, Characterization, and Applications of Dendrimer-Encapsulated Zero-Valent Ni Nanoparticles as Antimicrobial Agents

Dendrimers have emerged as one of the most promising, cost-effective synthesizing methodologies in which highly monodispersed metallic nanoparticles can be produced with varied chemical functionalities. In this report, we have investigated the synthesis and application of as-synthesized dendrimer-encapsulated zero-valent nickel “Ni(0)” nanoparticles (NPs), using a fourth generation (G4) NH2-terminated poly(amido)amine (PAMAM) dendrimer as the host template, as potential antimicrobial agents. Apparently, based on ultraviolet visible spectroscopy (UV-vis) and transmission electron microscopy (TEM) analyses, Ni(0) NPs with an average measured size less than 10 nm in diameter were formed within the interior void cavity of the dendrimer structure. X-ray diffraction (XRD) analysis indicates that the NPs exhibited a single-phased, face-centered-cubic (fcc) crystallographic structure. Furthermore, to evaluate the antimicrobial activity of the dendrimer-encapsulated Ni(0) NPs, disk diffusion assay and minimum inhibitory concentration (MIC) examinations, both antimicrobial tests, were conducted. Subsequently, UV-vis analyses, after exposure of the dendrimer-encapsulated Ni(0) NPs to both Gram-negative and Gram-positive bacteria, revealed that the dendrimer-encapsulated particles prevented the growth of bacteria during the culturing stage.

Transgene and immune gene expression following intramuscular injection of Atlantic salmon (Salmo salar L.) with DNA-releasing PLGA nano- and microparticles

The use of poly-(D,L-lactic-co-glycolic) acid (PLGA) particles as carriers for DNA delivery has received considerable attention in mammalian studies. DNA vaccination of fish has been shown to elicit durable transgene expression, but no reports exist on intramuscular administration of PLGA-encapsulated plasmid DNA (pDNA). We injected Atlantic salmon (Salmo salar L.) intramuscularly with a plasmid vector containing a luciferase (Photinus pyralis) reporter gene as a) naked pDNA, b) encapsulated into PLGA nano- (~320 nm) (NP) or microparticles (~4 μm) (MP), c) in an oil-based formulation, or with empty particles of both sizes. The ability of the different pDNA-treatments to induce transgene expression was analyzed through a 70-day experimental period. Anatomical distribution patterns and depot effects were determined by tracking isotope labeled pDNA. Muscle, head kidney and spleen from all treatment groups were analyzed for proinflammatory cytokines (TNF-α, IL-1β), antiviral genes (IFN-α, Mx) and cytotoxic T-cell markers (CD8, Eomes) at mRNA transcription levels at days 1, 2, 4 and 7. Histopathological examinations were performed on injection site samples from days 2, 7 and 30. Injection of either naked pDNA or the oil-formulation was superior to particle treatments for inducing transgene expression at early time-points. Empty particles of both sizes were able to induce proinflammatory immune responses as well as degenerative and inflammatory pathology at the injection site. Microparticles demonstrated injection site depots and an inflammatory pathology comparable to the oil-based formulation. In comparison, the distribution of NP-encapsulated pDNA resembled that of naked pDNA, although encapsulation into NPs significantly elevated the expression of antiviral genes in all tissues. Together the results indicate that while naked pDNA is most efficient for inducing transgene expression, the encapsulation of pDNA into NPs up-regulates antiviral responses that could be of benefit to DNA vaccination.

Cyclodextrin based nanosponges for pharmaceutical use: a review

Nanosponges are a novel class of hyper-crosslinked polymer based colloidal structures consisting of solid nanoparticles with colloidal sizes and nanosized cavities. These nano-sized colloidal carriers have been recently developed and proposed for drug delivery, since their use can solubilize poorly water-soluble drugs and provide prolonged release as well as improve a drug's bioavailability by modifying the pharmacokinetic parameters of actives. Development of nanosponges as drug delivery systems, with special reference to cyclodextrin based nanosponges, is presented in this article. In the current review, attempts have been made to illustrate the features of cyclodextrin based nanosponges and their applications in pharmaceutical formulations. Special emphasis has been placed on discussing the methods of preparation, characterization techniques and applications of these novel drug delivery carriers for therapeutic purposes. Nanosponges can be referred to as solid porous particles having a capacity to load drugs and other actives into their nanocavity; they can be formulated as oral, parenteral, topical or inhalation dosage forms. Nanosponges offer high drug loading compared to other nanocarriers and are thus suitable for solving issues related to stability, solubility and delayed release of actives. Controlled release of the loaded actives and solubility enhancement of poorly water-soluble drugs are major advantages of nanosponge drug delivery systems.

Nanoparticle-mediated delivery of TGF-β1 miRNA plasmid for preventing flexor tendon adhesion formation

Treatment of the disrupted digital flexor tendon is troublesome because of the lack of sufficient healing capacity and the formation of adhesions. Sustained gene delivery may be a promising approach of modulating gene expression in enhancing tendon healing and decreasing adhesions. In this study, a microRNA-based RNAi plasmid was used to specifically silence the expression of TGF-β1 gene associated with scar and adhesion formation in the flexor tendons. The miRNA plasmids were complexed with polylactic-co-glycolic acid (PLGA) nanoparticles to form nanoparticle/TGF-β1 miRNA plasmid (nanoparticle/plasmid) complexes. In vitro and in vivo transfection efficiencies experiments against tenocytes revealed that nanoparticle/plasmid complexes have significantly superior transfection efficiency over the lipofectamine/plasmid complexes. The gene and protein expression associated with adhesion of tendon treated with nanoparticle/plasmid complexes were evaluated by real-time PCR and immunoblotting. The grading of adhesions for tendons treated with nanoparticle/plasmid complexes was less severe than that treated with the nanoparticle/mock plasmid complexes. However, the ultimate strength of repaired tendons treated with nanoparticle/plasmid complexes was significantly lower than that of tendons treated with the nanoparticle/mock plasmid complexes.

The internalization of fluorescence-labeled PLA nanoparticles by macrophages

Rhodamine B (RhB)-labeled PLA nanoparticles were prepared through surface grafting copolymerization of glycidyl methacrylate (GMA) onto PLA nanoparticles during the emulsion/evaporation process. RhB firstly interacts with sodium dodecyl sulfate (SDS) through electrostatic interaction to form hydrophobic complex (SDS-RhB). Due to the high-affinity of SDS-RhB with GMA, hydrophilic RhB can be successfully combined into PLA nanoparticles. The internalization of RhB-labeled PLA nanoparticles by macrophages was investigated with fluorescence microscope technology. The effects of the PLA nanoparticle surface nature and size on the internalization were investigated. The results indicate that the PLA particles smaller than 200 nm can avoid the uptake of phagocytosis. The bigger PLA particles (300 nm) with polyethylene glycol (PEG) surface showed less internalization by macrophage compared with those with poly(ethylene oxide-propylene oxide) copolymer (F127) or poly(vinyl alcohol) (PVA) surface. The "stealth" function of PEG on the PLA nanoparticles from internalization of macrophages due to the low protein adsorption is revealed by electrochemical impedance technology.

The delivery of thrombi-specific nanoparticles incorporating oligonucleotides into injured cerebrovascular endothelium

In acute vascular events, the endothelium derived tissue factor (TF) is the trigger of the coagulation cascade. In this study, EGFP-EGF1 protein-conjugated PEG-PLGA nanoparticle was employed as a TF targeting vehicle, the NF-κB decoy oligonucleotides (ODNs) was incorporated into it and the resulting EGF1-EGFP-NP-ODNs were evaluated as a vector for therapy of cortex infarction. At 2 h after transfection of TF expressed rat brain capillary endothelial cell, EGF1-EGFP-NP-ODNs was more efficiently internalized and located in the cytoplasm than NP-ODNs. At 4 h and 6 h after administration, ODNs were present in the nuclei and obviously inhibited the TF expression. At 6 h after i.v. administration in vivo, most EGF1-EGFP-NP were accumulated in the embolism vessels, distributed in the damaged endothelial cells and lowered the TF expression. At 24 h after i.v. administration, MR imaging of cortex infarcts were predominantly dwindled.

Novel luminescent silica nanoparticles (LSN): p53 gene delivery system in breast cancer in vitro and in vivo

OBJECTIVES

Mutations in the p53 tumor suppressor gene are one among the most common genetic abnormalities to be described in breast cancer. However, there are a few recant reports on non-viral vector-mediated p53 gene delivery in breast cancer.

METHODS

A new formulation of luminescent silica nanoparticles (LSNs) for gene delivery was produced by the two-step method with slight modification.

KEY FINDINGS

The pp53 plasmid constructs (p53-EGFP)/LSNs complexes were transfected into human breast cancer cell (MCF-7) and transfection efficiency was determined by FACS analysis. The gene expression was determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis respectively. Further the growth inhibition through induced apoptosis with pp53-EGFP/LSNs complex were assessed by trypan blue exclusion assay and annexin V staining, respectively. Interestingly the in vivo biodistribution of plasmid DNA study revealed the occurrence was investigated by PCR and RT-PCR. The transfection efficiency of LSNs showed the highest transfection efficiency among the LSN formulation was higher than that of commercially available Lipofectin®. The LSNs-mediated transfection of the p53 gene resulted in efficient high level of wild-type p53 mRNA and protein expression levels in MCF-7 cells. Selected tissues were analyzed for any potential toxicity by histological analysis the efficient reestablishment of wild-type p53 function in breast cancer cells restored the p53 dependent apoptotic pathway.

CONCLUSIONS

Taken together, our results reveal that cationic LSN-mediated p53 gene delivery may have potential application as a non-viral vector-mediated breast cancer gene therapy due to its effective induction of apoptosis and tumor growth inhibition.

Effect of experimental parameters on the formation of alginate–chitosan nanoparticles and evaluation of their potential application as DNA carrier

This study introduces a new procedure to prepare alginate-chitosan nanoparticles and examines several experimental parameters in relation to their formation and characteristics. Using DLS and TEM analysis, nanoparticle formation was shown to be predominantly affected by the ratio of alginate to chitosan, the molecular weight of the biopolymers and the solution pH. We report a method that results in spherical particles with mean diameters ranging from 323 nm to 1.6 microm, depending on the preparation conditions. The smallest particles were formed using lower molecular weight polymers with pH between 5.0 and 5.6 and having an alginate/chitosan weight ratio of 1:1.5. We have shown that DNA can be loaded with 60% association efficiency. Our system demonstrates suitable size, loading and release characteristics for application in drug- and gene-delivery systems.

Oral DNA vaccination of rainbow trout, Oncorhynchus mykiss (Walbaum), against infectious haematopoietic necrosis virus using PLGA [Poly(D,L-Lactic-Co-Glycolic Acid)] nanoparticles

A DNA vaccine against infectious haematopoietic necrosis virus (IHNV) is effective at protecting rainbow trout, Oncorhynchus mykiss, against disease, but intramuscular injection is required and makes the vaccine impractical for use in the freshwater rainbow trout farming industry. Poly (D,L-lactic-co-glycolic acid) (PLGA) is a U.S. Food and Drug Administration (FDA) approved polymer that can be used to deliver DNA vaccines. We evaluated the in vivo absorption of PLGA nanoparticles containing coumarin-6 when added to a fish food pellet. We demonstrated that rainbow trout will eat PLGA nanoparticle coated feed and that these nanoparticles can be detected in the epithelial cells of the lower intestine within 96 h after feeding. We also detected low levels of gene expression and anti-IHNV neutralizing antibodies when fish were fed or intubated with PLGA nanoparticles containing IHNV G gene plasmid. A virus challenge evaluation suggested a slight increase in survival at 6 weeks post-vaccination in fish that received a high dose of the oral vaccine, but there was no difference when additional fish were challenged at 10 weeks post-vaccination. The results of this study suggest that it is possible to induce an immune response using an orally delivered DNA vaccine, but the current system needs improvement.

Nanomedical system for nucleic acid drugs created with the biodegradable nanoparticle platform

Nanomedical applications of biodegradable poly(DL-lactide-co-glycolide) (PLGA) nanoparticles (NPs) developed are discussed in this review. A surface-functionalized PLGA NP platform for drug delivery was established to encapsulate a number of macromolecular drugs such as peptides and nucleic acids as well as low-molecular-weight drugs by the emulsion solvent diffusion method. The interaction of PLGA NPs with cells and tissues could be controlled by changing the surface properties of NPs, suggesting their potential utility for the intracellular drug delivery of nucleic acid-based drugs. Furthermore, orally administered NF-κB decoy oligonucleotide-loaded CS-PLGA NPs are also useful in treating experimental colitis. These approaches using surface-modified PLGA NPs could be able to open new possibilities for nucleic acid-based drug delivery via noninvasive administration method.

Patterning human stem cells and endothelial cells with laser printing for cardiac regeneration

Recent study showed that mesenchymal stem cells (MSC) could inhibit apoptosis of endothelial cells in hypoxic condition, increase their survival, and stimulate the angiogenesis process. In this project we applied Laser-Induced-Forward-Transfer (LIFT) cell printing technique and prepared a cardiac patch seeded with human umbilical vein endothelial cells (HUVEC) and human MSC (hMSC) in a defined pattern for cardiac regeneration. We seeded HUVEC and hMSC in a defined pattern on a Polyester urethane urea (PEUU) cardiac patch. On control patches an equal amount of cells was randomly seeded without LIFT. Patches were cultivated in vitro or transplanted in vivo to the infarcted zone of rat hearts after LAD-ligation. Cardiac performance was measured by left ventricular catheterization 8 weeks post infarction. Thereafter hearts were perfused with fluorescein tomato lectin for the assessment of functional blood vessels and stored for histology analyses. We demonstrated that LIFT-derived cell seeding pattern definitely modified growth characteristics of co-cultured HUVEC and hMSC leading to increased vessel formation and found significant functional improvement of infarcted hearts following transplantation of a LIFT-tissue engineered cardiac patch. Further, we could show enhanced capillary density and integration of human cells into the functionally connected vessels of murine vascular system. LIFT-based Tissue Engineering of cardiac patches for the treatment of myocardial infarction might improve wound healing and functional preservation.

AAV and compacted DNA nanoparticles for the treatment of retinal disorders: challenges and future prospects

Gene therapy based on delivery of viral and nonviral vectors has shown great promise for the treatment of human ocular diseases; however, limitations have consistently prevented its widespread clinical application. Viral vectors have generally been better in terms of efficiency but have safety concerns. Nonviral vectors, on the other hand, offer safety but have often been disappointing in terms of efficiency of nuclear delivery and gene expression. Extensive animal studies have reported significant progress using both systems, but thus far only a few studies have shown promise in human clinical trials. This article reviews both viral and nonviral work with focus on two candidates for clinical ocular application--AAV and nanoparticles. Of particular interest are various requirements for successful clinical application of these technologies including vector trafficking, delivery, specific gene expression, and treatment safety, and tolerance.

Preparation and in-vitro/in-vivo evaluation of surface-modified poly (lactide-co-glycolide) fluorescent nanoparticles

OBJECTIVE

The aim was to develop biodegradable nanoparticles suitable for cellular delivery of chemotherapeutic drugs.

METHODS

Poly (lactide-co-glycolide) (PLGA) nanoparticles were prepared using a modified solvent evaporation method. Chitosan and calcium chloride were tested as surface modifiers. Coumarin-6 was incorporated into some formulations as a fluorescent marker.

KEY FINDINGS

The median size of the particles was between 400 nm and 7 microm, and scanning electron microscope pictures showed that the particles were smooth and spherical. The zeta potentials of the particles with and without surface modifier ranged between -25.7 mV and -7.0 mV, respectively. Fluorescence microscopy and flow cytometry (FACS) analysis showed that smaller surface-modified particles were efficiently internalised by neoplastic 4T1 cells. Image analysis of frozen tissue sections from Balb/c mice given nanoparticles via the tail vein showed that the particles were distributed preferentially into the lungs, followed by the liver, spleen, kidney and heart.

CONCLUSIONS

Chitosan-modified PLGA nanoparticles showed significant uptake by neoplastic 4T1 cells, and were distributed to several major organs frequently seen as sites of cancer metastasis in mice.

Formulation of chitosan-TPP-pDNA nanocapsules for gene therapy applications

The encapsulation of DNA inside nanoparticles meant for gene delivery applications is a challenging process where several parameters need to be modulated in order to design nanocapsules with specific tailored characteristics. The purpose of this study was to investigate and improve the formulation parameters of plasmid DNA (pDNA) loaded in chitosan nanocapsules using tripolyphosphate (TPP) as polyanionic crosslinker. Nanocapsule morphology and encapsulation efficiency were analyzed as a function of chitosan degree of deacetylation and chitosan-TPP ratio. The manipulation of these parameters influenced not only the particle size but also the encapsulation and release of pDNA. Consequently the transfection efficiency of the nanoparticulated systems was also enhanced with the optimization of the particle characteristics. Overall, the differently formulated nanoparticulated systems possess singular properties that can be employed according to the desired gene delivery application.