DNA delivery via cationic solid lipid nanoparticles (SLNs)

Preparation and Optimization of MiR-375 Nano-Vector Using Two Novel Chitosan-Coated Nano-Structured Lipid Carriers as Gene Therapy for Hepatocellular Carcinoma

Currently, there is still a lack of effective carriers with minimal side effects to deliver therapeutic miRNA. Thus, it is crucial to optimize novel drug delivery systems. MiR-375 has proven superior therapeutic potency in Hepatocellular carcinoma (HCC). The purpose of this study was to fabricate 2 novel and smart nano-carriers for the transportation efficiency of miR-375 in HCC cells and enhance its anti-tumor effects. We established the miR-375 construct through the pEGP- miR expression vector. Two nano-carriers of solid/liquid lipids and chitosan (CS) were strategically selected, prepared by high-speed homogenization, and optimized by varying nano-formulation factors. Thus, the two best nano-formulations were designated as F1 (0.5% CS) and F2 (1.5% CS) and were evaluated for miR-375 conjugation efficiency by gel electrophoresis and nanodrop assessment. Then, physio-chemical characteristics and stability tests for the miR-375 nano-plexes were all studied. Next, its efficiencies as replacement therapy in HepG2 cells have been assessed by fluorescence microscopy, flow cytometry, and cytotoxicity assay. The obtained data showed that two cationic nanostructured solid/liquid lipid carriers (NSLCs); F1 and F2 typically had the best physio-chemical parameters and long-term stability. Moreover, both F1 and F2 could form nano-plexes with the anionic miR-375 construct at weight ratios 250/1 and 50/1 via electrostatic interactions. In addition, these nano-plexes exhibited physical stability after three months and protected miR-375 from degradation in the presence of 50% fetal bovine serum (FBS). Furthermore, both nano-plexes could simultaneously deliver miR-375 into HepG2 cells and they ensure miR re-expression even in the presence of 50% FBS compared to free miR-375 (p-value < 0.001). Moreover, both F1 and F2 alone significantly exhibited minimal cytotoxicity in treated cells. In contrast, the nano-plexes significantly inhibited cell growth compared to free miR-375 or doxorubicin (DOX), respectively. More importantly, F2/miR-375 nano-plex exhibited more anti-proliferative activity in treated cells although its IC50 value was 55 times lower than DOX (p-value < 0.001). Collectively, our findings clearly emphasized the multifunctionality of the two CS-coated NSLCs in terms of their enhanced biocompatibility, biostability, conjugation, and transfection efficiency of therapeutic miR-375. Therefore, the NSLCs/miR-375 nano-plexes could serve as a novel and promising therapeutic strategy for HCC.

Improved biopharmaceutical performance of antipsychotic drug using lipid nanoparticles via intraperitoneal route

This study aims to develop, characterize, and examine olanzapine-loaded solid lipid nanocarriers (OLAN-SLNs) for effective brain delivery. OLAN has poor water solubility and low penetration through blood-brain barrier (BBB). Herein, OLAN-SLNs were fabricated using high-pressure homogenization (HPH) method followed by their investigation for particle properties. Moreover, in vitro release and in vivo pharmacokinetics profiles of OLAN-SLNs were compared with pure drug. Anti-psychotic activity was performed in LPS-induced psychosis mice model. Furthermore, expressions of the COX-2 and NF-κB were measured trailed by histopathological examination. The optimized formulation demonstrated nanoparticle size (149.1 nm) with rounded morphology, negative zeta potential (-28.9 mV), lower PDI (0.334), and excellent entrapment efficiency (95%). OLAN-SLNs significantly retarded the drug release and showed sustained release pattern as compared to OLAN suspension. Significantly enhanced bioavailability (ninefold) was demonstrated in OLAN-SLNs when compared with OLAN suspension. Behavioral tests showed significantly less immobility and more struggling time in OLAN-SLNs treated mice group. Additionally, reduced expression of COX-2 and -NF κB in brain was found. Altogether, it can be concluded that SLNs have the potential to deliver active pharmaceutical ingredients to brain, most importantly to enhance their bioavailability and antipsychotic effect, as indicated for OLAN in this study.

Modification of Lipid-Based Nanoparticles: An Efficient Delivery System for Nucleic Acid-Based Immunotherapy

Lipid-based nanoparticles (LBNPs) are biocompatible and biodegradable vesicles that are considered to be one of the most efficient drug delivery platforms. Due to the prominent advantages, such as long circulation time, slow drug release, reduced toxicity, high transfection efficiency, and endosomal escape capacity, such synthetic nanoparticles have been widely used for carrying genetic therapeutics, particularly nucleic acids that can be applied in the treatment for various diseases, including congenital diseases, cancers, virus infections, and chronic inflammations. Despite great merits and multiple successful applications, many extracellular and intracellular barriers remain and greatly impair delivery efficacy and therapeutic outcomes. As such, the current state of knowledge and pitfalls regarding the gene delivery and construction of LBNPs will be initially summarized. In order to develop a new generation of LBNPs for improved delivery profiles and therapeutic effects, the modification strategies of LBNPs will be reviewed. On the basis of these developed modifications, the performance of LBNPs as therapeutic nanoplatforms have been greatly improved and extensively applied in immunotherapies, including infectious diseases and cancers. However, the therapeutic applications of LBNPs systems are still limited due to the undesirable endosomal escape, potential aggregation, and the inefficient encapsulation of therapeutics. Herein, we will review and discuss recent advances and remaining challenges in the development of LBNPs for nucleic acid-based immunotherapy.

Effect of Cationic Lipid Nanoparticle Loaded siRNA with Stearylamine against Chikungunya Virus

Chikungunya is an infectious disease caused by mosquito-transmitted chikungunya virus (CHIKV). It was reported that NS1 and E2 siRNAs administration demonstrated CHIKV inhibition in in vitro as well as in vivo systems. Cationic lipids are promising for designing safe non-viral vectors and are beneficial in treating chikungunya. In this study, nanodelivery systems (hybrid polymeric/solid lipid nanoparticles) using cationic lipids (stearylamine, C9 lipid, and dioctadecylamine) and polymers (branched PEI-g-PEG -PEG) were prepared, characterized, and complexed with siRNA. The four developed delivery systems (F1, F2, F3, and F4) were assessed for stability and potential toxicities against CHIKV. In comparison to the other nanodelivery systems, F4 containing stearylamine (Octadecylamine; ODA), with an induced optimum cationic charge of 45.7 mV in the range of 152.1 nm, allowed maximum siRNA complexation, better stability, and higher transfection, with strong inhibition against the E2 and NS1 genes of CHIKV. The study concludes that cationic lipid-like ODA with ease of synthesis and characterization showed maximum complexation by structural condensation of siRNA owing to high transfection alone. Synergistic inhibition of CHIKV along with siRNA was demonstrated in both in vitro and in vivo models. Therefore, ODA-based cationic lipid nanoparticles can be explored as safe, potent, and efficient nonviral vectors overcoming siRNA in vivo complexities against chikungunya.

Combined delivery of TLR2 and TLR7 agonists by Nanostructured lipid carriers induces potent vaccine adjuvant activity in mice

Toll-like receptor (TLR) agonists are promising adjuvants and the combination of TLR agonists enhance immune responses by providing synergistic immune activity via triggering different signalling pathways. However, systematic cytotoxicity due to the immediate release of such immune potentiators from the site of injection hampers its clinical performance. Nanostructured lipid carriers (NLCs) offer a possibility to incorporate multiple TLR agonists with high encapsulation efficiency and slow drug release. Herein, we synthesized NLCs from didodecyldimethylammonium bromide (D₁₂DAB) and oleic acid and used these to co-encapsulate a Pam₂CS derivative (T-2, TLR2 agonist) with an imidazoquinoline derivative (T-7, TLR7 agonist) as a combination vaccine adjuvant. Hydrodynamic diameter and zeta potential of the prepared NLCs were found to be in the range of 200-500 nm and 23-27 mV, respectively. Spherical shape and size of prepared NLCs were also assessed through Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) analysis. In-vitro release studies of T-7 demonstrated sustained release and the addition of lipopeptide T-2 augmented encapsulation efficiency (from 84 to 92.9%) with a slight trigger in the release percentage. All NLC formulations were screened in TLR2/1, TLR2/6, TLR7 and TLR8 reporter cell lines and loaded NLC formulation showed high TLR2 and TLR7 agonistic activity. Adjuvant potency was evaluated through intramuscular immunization of female C57BL/6 mice with recombinant hepatitis B surface antigen and influenza hemagglutinin protein. T-2 and T-7 loaded NLCs induced good protective efficacy in mice challenged with a lethal dose of influenza virus.

Development and Evaluation of Solid Witepsol Nanoparticles for Gene Delivery

Objectives

Gene therapy approaches have become increasingly attractive in the medical, pharmaceutical, and biotechnological industries due to their applicability in the treatment of diseases with no effective conventional therapy. Non-viral delivery using cationic solid lipid nanoparticles (cSLNs) can be useful to introduce large nucleic acids to target cells. A careful selection of components and their amounts is critical to obtain a successful delivery system. In this study, solid Witepsol nanoparticles were formulated, characterized, and evaluated in vitro for gene delivery purposes.

Materials and Methods

Solid Witepsol nanoparticles were formulated through the microemulsion dilution technique using two grades of Witepsol and three surfactants, namely Cremephor RH40, Kolliphor HS15, and Peceol. Dimethyldioctadecylammonium bromide was incorporated into the system as a cationic lipid. Twelve combinations of these ingredients were formulated. The obtained nanoparticles were then evaluated for particle size, zeta potential, DNA binding and protection ability, cytotoxicity, and transfection ability.

Results

Particle sizes of the prepared cationic cSLNs were between 13.43±0.06 and 68.80±0.78 nm. Their zeta potential, which is important for DNA binding efficiency, was determined at >+40 mV. Gel retardation assays revealed that the obtained cSLNs can form a compact complex with plasmid DNA (pDNA) encoding green fluorescent protein and that this complex can protect pDNA from DNase I-mediated degradation. Cytotoxicity evaluation of nanoparticles was performed on the L929 cell line. In vitro transfection data revealed that solid Witepsol nanoparticles could effectively transfect fibroblasts.

Conclusion

Our findings indicate that solid Witepsol nanoparticles prepared using the microemulsion dilution technique are promising non-viral delivery systems for gene therapy.

Self-Assembled pH-Sensitive Polymeric Nanoparticles for the Inflammation-Targeted Delivery of Cu/Zn-Superoxide Dismutase

The use of superoxide dismutase (SOD) is currently limited by its short half-life, rapid plasma clearance rate, and instability. We synthesized a small library of biofriendly amphiphilic polymers that comprise methoxy poly(ethylene glycol)-poly(cyclohexane-1,4-diyl acetone dimethyleneketal) (mPEG-PCADK) and mPEG-poly((cyclohexane_86.7%, 1,5-pentanediol_13.3%)-1,4-diyl acetone dimethylene ketal) (PK3) for the targeted delivery of SOD. The novel polymers could self-assemble into micellar nanoparticles with favorable hydrolysis kinetics, biocompatibility, long circulation time, and inflammation-targeting effects. These materials generated a better pH-response curve and exhibited better hydrolytic kinetic behavior than PCADK and PK3. The polymers showed good biocompatibility with protein drugs and did not induce an acidic microenvironment during degradation in contrast to materials such as PEG-block-poly(lactic-co-glycolic acid) (PLGA) and PLGA. The SOD that contained reverse micelles based on mPEG2000-PCADK exhibited good circulation and inflammation-targeting properties. Pharmacodynamic results indicated exceptional antioxidant and anti-inflammatory activities in a rat adjuvant-induced arthritis model and a rat peritonitis model. These results suggest that these copolymers are ideal protein carriers for targeting inflammation treatment.

A Cationic Stearamide-based Solid Lipid Nanoparticle for Delivering Yamanaka Factors: Evaluation of the Transfection Efficiency

Induced pluripotent stem cells (IPSC) are preferred as an alternative source for regenerative medicine, disease modeling, and drug screening due to their unique properties. As seen from the previous studies in the literature, most of the vector systems to transfer reprogramming factors are viral-based and have some well-known limitations. This study aims to develop a non-viral vector system for the transfection of reprogramming factors. Cationic stearamide lipid nanoparticles (CSLN) were prepared via the solvent diffusion method. The obtained CSLNs were used for the delivery of plasmid DNA (pDNA) encoding Oct3/4, Sox2, Klf4, and GFP to fibroblast cell lines. The optimization studies, for zeta potential and particle size of the conjugate, was performed to achieve high cell viability. CSLN63 with 36.5±0.06 mV zeta potential and 173.6±13.91 nm size was used for the transfection of Fibroblast cells. The transfection efficiency was observed by following GFP expression and was found as 70 %±0.11. The expression of the Oct4, Sox2, Klf4 was determined by RT-qPCR; an increase was observed after the 12th cycle in Klf4 (Ct averages: 13,41), Sox2 (Ct averages; 12,4), Oct4 (Ct average; 13,77). The tendency of colonization was observed. The upregulation efficiency of Oct4 and SSEA-1 with CSLN and another non-viral vector designed for the transportation of Yamanaka factors developed in our lab previously were compared with flow cytometer analysis.

A brief review on solid lipid nanoparticles: part and parcel of contemporary drug delivery systems

Drug delivery technology has a wide spectrum, which is continuously being upgraded at a stupendous speed. Different fabricated nanoparticles and drugs possessing low solubility and poor pharmacokinetic profiles are the two major substances extensively delivered to target sites. Among the colloidal carriers, nanolipid dispersions (liposomes, deformable liposomes, virosomes, ethosomes, and solid lipid nanoparticles) are ideal delivery systems with the advantages of biodegradation and nontoxicity. Among them, nano-structured lipid carriers and solid lipid nanoparticles (SLNs) are dominant, which can be modified to exhibit various advantages, compared to liposomes and polymeric nanoparticles. Nano-structured lipid carriers and SLNs are non-biotoxic since they are biodegradable. Besides, they are highly stable. Their (nano-structured lipid carriers and SLNs) morphology, structural characteristics, ingredients used for preparation, techniques for their production, and characterization using various methods are discussed in this review. Also, although nano-structured lipid carriers and SLNs are based on lipids and surfactants, the effect of these two matrixes to build excipients is also discussed together with their pharmacological significance with novel theranostic approaches, stability and storage.

Development of levosulpiride-loaded solid lipid nanoparticles and their in vitro and in vivo comparison with commercial product

The aim of this study was to develop levosulpiride-loaded solid lipid nanoparticles (SLNs) with enhanced solubilisation and bioavailability. The levosulpiride loaded-SLNs were composed of levosulpiride, stearic acid, and tween 80 in their respective weight ratios of (1, 5, and 1.5 mg) dissolved in 1 ml distilled water. Physicochemical properties of the SLNs such as particle size, shape, crystallinity, and chemical interaction were evaluated. Further, the in vitro drug dissolution, pharmacokinetic and stability studies of the SLNs were performed. The SLNs were rounded shaped stable nanoparticles with average diameter of 200 nm. They demonstrate 1.5- and 3-fold better drug dissolution when compared with the commercial product and levosulpiride powder, respectively. The SLNs enhanced the bioavailability of levosulpiride 3 times and 7 times, respectively, when compared with the commercial product and levosulpiride powder. It can be concluded that SLNs are capable to improve the dissolution and bioavailability of levosulpiride, even more than the commercial product.

Nanomaterial Exposure Induced Neutrophil Extracellular Traps: A New Target in Inflammation and Innate Immunity

Nanotechnology has become a novel subject with impact in many research and technology areas. Nanoparticles (NPs), as a key component in nanotechnology, are widely used in many areas such as optical, magnetic, electrical, and mechanical engineering. The biomedical and pharmaceutical industries have embraced NPs as a viable drug delivery modality. As such, the potential for NP-induced cytotoxicity has emerged as a major concern for NP drug delivery systems. Thus, it is important to understand how NPs affect the innate immune system. As the most abundant myeloid cell type in innate immune responses, neutrophils are critical for concerns about potentially toxic side effects of NPs. When activated by innate immune stimuli, neutrophils may initiate NETosis to release neutrophil extracellular traps (NETs). Herein, we have reviewed the relationship between NPs and the induction of NETosis and release of NETs.

Colloidally Stable Small Unilamellar Stearyl Amine Lipoplexes for Effective BMP-9 Gene Delivery to Stem Cells for Osteogenic Differentiation

The biocompatibility of cationic liposomes has led to their clinical translation in gene delivery and their application apart from cancer to cardiovascular diseases, osteoporosis, metabolic diseases, and more. We have prepared PEGylated stearyl amine (pegSA) lipoplexes meticulously considering the physicochemical properties and formulation parameters to prepare single unilamellar vesicles (SUV) of < 100 nm size which retain their SUV nature upon complexation with pDNA rather than the conventional lipoplexes which show multilamellar nature. The developed PEGylated SA lipoplexes (pegSA lipoplexes) showed a lower N/P ratio (1.5) for BMP-9 gene complexation while maintaining the SUV character with a unique shape (square and triangular lipoplexes). Colloidal and pDNA complexation stability in the presence of electrolytes and serum indicates the suitability for intravenous administration for delivery of lipoplexes to bone marrow mesenchymal stem cells through sinusoidal vessels in bone marrow. Moreover, lower charge density of lipoplexes and low oxidative stress led to lower toxicity of lipoplexes to the C2C12 cells, NIH 3T3 cells, and erythrocytes. Transfection studies showed efficient gene delivery to C2C12 cells inducing osteogenic differentiation through BMP-9 expression as shown by enhanced calcium deposition in vitro, proving the potential of lipoplexes for bone regeneration. In vivo acute toxicity studies further demonstrated safety of the developed lipoplexes. Developed pegSA lipoplexes show potential for further in vivo preclinical evaluation to establish the proof of concept.

Astaxanthin-Loaded Nanostructured Lipid Carriers for Preservation of Antioxidant Activity

Astaxanthin is a xanthophyll carotenoid showing efficient scavenging ability and represents an interesting candidate in the development of new therapies for preventing and treating oxidative stress-related pathologies. However, its high lipophilicity and thermolability often limits its antioxidant efficacy in human applications. Here, we developed a formulation of lipid carriers to protect astaxanthin’s antioxidant activity. The synthesis of natural astaxanthin-loaded nanostructured lipid carriers using a green process with sunflower oil as liquid lipid is presented. Their antioxidant activity was measured by α-Tocopherol Equivalent Antioxidant Capacity assay and was compared to those of both natural astaxanthin and α-tocopherol. Characterizations by dynamic light scattering, atomic force microscopy, and scattering electron microscopy techniques were carried out and showed spherical and surface negative charged particles with z-average and polydispersity values of ~60 nm and ~0.3, respectively. Astaxanthin loading was also investigated showing an astaxanthin recovery of more than 90% after synthesis of nanostructured lipid carriers. These results demonstrate the capability of the formulation to stabilize astaxanthin molecule and preserve and enhance the antioxidant activity.

Cholesteryl oleate-loaded cationic solid lipid nanoparticles as carriers for efficient gene-silencing therapy

Background

Cationic solid lipid nanoparticles (SLNs) have been given considerable attention for therapeutic nucleic acid delivery owing to their advantages over viral and other nanoparticle delivery systems. However, poor delivery efficiency and complex formulations hinder the clinical translation of SLNs.

Aim

The aim of this study was to formulate and characterize SLNs incorporating the cholesterol derivative cholesteryl oleate to produce SLN–nucleic acid complexes with reduced cytotoxicity and more efficient cellular uptake.

Methods

Five cholesteryl oleate-containing formulations were prepared. Laser diffraction and laser Doppler microelectrophoresis were used to evaluate particle size and zeta potential, respectively. Nanoparticle morphology was analyzed using electron microscopy. Cytotoxicity and cellular uptake of lipoplexes were evaluated using flow cytometry and fluorescence microscopy. The gene inhibition capacity of the lipoplexes was assessed using siRNAs to block constitutive luciferase expression.

Results

We obtained nanoparticles with a mean diameter of approximately 150–200 nm in size and zeta potential values of 25–40 mV. SLN formulations with intermediate concentrations of cholesteryl oleate exhibited good stability and spherical structures with no aggregation. No cell toxicity of any reference SLN was observed. Finally, cellular uptake experiments with DNA-and RNA-SLNs were performed to select one reference with superior transient transfection efficiency that significantly decreased gene activity upon siRNA complexation.

Conclusion

The results indicate that cholesteryl oleate-loaded SLNs are a safe and effective platform for nonviral nucleic acid delivery.

Lipid-based nanocarriers for the oral administration of biopharmaceutics

Biopharmaceutics have been recognized as the drugs of choice for the treatment of several diseases, mainly due to their high selectivity and potent action. Nonetheless, their oral administration is a rather challenging problem, since their bioavailability is significantly hindered by various physiological barriers along the GI tract, including their acid-induced hydrolysis in the stomach, their enzymatic degradation throughout the GI tract and their poor mucosa permeability. Lipid-based nanocarriers represent a viable means for enhancing the oral bioavailability of biomolecules while diminishing toxicity-related issues. The present review describes the main physiological barriers limiting the oral bioavailability of macromolecules and highlights recent advances in the field of lipid-based carriers as well as the respective lipid intestinal absorption mechanisms.

Preparation and in vitro evaluation of vaginal formulations including siRNA and paclitaxel-loaded SLNs for cervical cancer

Cervical cancer is one of the most life threatening types of cancer among women and is generally resistant to chemotherapy. The objective of this study was to prepare a vaginal suppository containing a chemotherapeutic agent and a genetic material that can be applied locally for cervical cancer. Paclitaxel was selected as the chemotherapeutic agent and siRNA which inhibits BCL-2 oncogene was selected as the genetic material. Bcl-2 siRNA, paclitaxel and paclitaxel/Bcl-2 siRNA combination were incorporated into solid lipid nanoparticles (SLNs) and were dispersed separately in vaginal suppositories prepared with PEG 6000. Physicochemical properties of SLNs, their cytotoxicities on HeLa cell lines and also the effect of SLNs on the total protein amount of the cells were examined followed by the investigation of release rates of the active materials from the SLNs prepared. Average diameters of all SLNs prepared were below 180nm with a positive zeta potential value between +22.20 and +48.16mV at the pH range of 4.2 and 7.4. The release of Bcl-2 siRNA from SLNs incorporated Bcl-2 siRNA and the release of paclitaxel (PTX) from PTX incorporated SLNs were completed within 12h and 36h. SLNs incorporating Bcl-2 siRNA and paclitaxel/Bcl-2 siRNA were found to be more toxic when compared to paclitaxel incorporated SLN and placebo SLN. The disintegration of the vaginal suppositories as well as the release of the SLNs was completed within 2 h. This study indicates that vaginal suppository containing SLNs can bring the advantages of the simultaneous delivery of paclitaxel and siRNA via vaginal route with no help from professionals.

Progresses towards safe and efficient gene therapy vectors

The emergence of genetic engineering at the beginning of the 1970′s opened the era of biomedical technologies, which aims to improve human health using genetic manipulation techniques in a clinical context. Gene therapy represents an innovating and appealing strategy for treatment of human diseases, which utilizes vehicles or vectors for delivering therapeutic genes into the patients' body. However, a few past unsuccessful events that negatively marked the beginning of gene therapy resulted in the need for further studies regarding the design and biology of gene therapy vectors, so that this innovating treatment approach can successfully move from bench to bedside. In this paper, we review the major gene delivery vectors and recent improvements made in their design meant to overcome the issues that commonly arise with the use of gene therapy vectors. At the end of the manuscript, we summarized the main advantages and disadvantages of common gene therapy vectors and we discuss possible future directions for potential therapeutic vectors.

Revealing the potential of Didodecyldimethylammonium bromide as efficient scaffold for fabrication of nano liquid crystalline structures

To exploit the potential of Didodecyldimethylammonium bromide (D12DAB) as a core lipidic constituent, an attempt was made to fabricate and optimize cationic nanostructured lipid carriers (cNLCs) using a cost-effective microemulsification methodology. Designed composition was optimized by studying the effect of different microemulsion components on D12DAB cNLCs characteristics. ​Spherical shaped D12DAB cNLCs were obtained with an average size of ∼160 nm and zeta potential of +30.2 mV. Differential Scanning Calorimetry (DSC) depicted the presence of thermotropic character, whereas polarized optical microscopy confirmed the mesophase like behavior of D12DAB based cNLCs. In addition, hemolysis analysis revealed that the toxicity was concentration dependent as LC50 was reached at a concentration of 50 μg/mL of cNLCs. This class of cNLCs is expected to become a potent candidate for a broad spectrum of medicaments as carriers, targeting for pharmaceutical and medicinal purposes, due to the combination of a hard lipid with a soft lipid, where the liquid crystalline structure of the lipid co-exists.

Solid Lipid Nanoparticles as Efficient Drug and Gene Delivery Systems: Recent Breakthroughs

In recent years, nanomaterials have been widely applied as advanced drug and gene delivery nanosystems. Among them, solid lipid nanoparticles (SLNs) have attracted great attention as colloidal drug delivery systems for incorporating hydrophilic or lipophilic drugs and various macromolecules as well as proteins and nucleic acids. Therefore, SLNs offer great promise for controlled and site specific drug and gene delivery. This article includes general information about SLN structures and properties, production procedures, characterization. In addition, recent progress on development of drug and gene delivery systems using SLNs was reviewed.

The impact of cationic solid lipid nanoparticles on human neutrophil activation and formation of neutrophil extracellular traps (NETs)

Cationic solid lipid nanoparticles (cSLNs) are extensively employed as the nanocarriers for drug/gene targeting to tumors and the brain. Investigation into the possible immune response of cSLNs is still lacking. The aim of this study was to evaluate the impact of cSLNs upon the activation of human polymorphonuclear neutrophil cells (PMNs). The cytotoxicity, pro-inflammatory mediators, Ca(2+) mobilization, mitogen-activated protein kinases (MAPKs), and neutrophil extracellular traps (NETs) as the indicators of PMN stimulation were examined in this work. The cSLNs presented a diameter of 195 nm with a zeta potential of 44 mV. The cSLNs could interact with the cell membrane to produce a direct membrane lysis and the subsequent cytotoxicity according to lactate dehydrogenase (LDH) elevation. The interaction of cSLNs with the membrane also triggered a Ca(2+) influx, followed by the induction of oxidative stress and degranulation. The cationic nanoparticles elevated the levels of superoxide anion and elastase by 24- and 9-fold, respectively. The PMN activation by cSLNs promoted the phosphorylation of p38 and Jun-N-terminal kinases (JNK) but not extracellular signal-regulated kinases (ERK). The imaging of scanning electron microscopy (SEM) and immunofluorescence demonstrated the production of NETs by cSLNs. This phenomenon was not significant for the neutral SLNs (nSLNs), although histones in NETs also increased after treatment of nSLNs. Our results suggest an important role of cSLNs in governing the activation of human neutrophils.

DNA-encapsulated magnesium phosphate nanoparticles elicit both humoral and cellular immune responses in mice

The efficacy of pEGFP (plasmid expressing enhanced green fluorescent protein)-encapsulated PEGylated (meaning polyethylene glycol coated) magnesium phosphate nanoparticles (referred to as MgPi-pEGFP nanoparticles) for the induction of immune responses was investigated in a mouse model. MgPi-pEGFP nanoparticles induced enhanced serum antibody and antigen-specific T-lymphocyte responses, as well as increased IFN-? and IL-12 levels compared to naked pEGFP when administered via intravenous, intraperitoneal or intramuscular routes. A significant macrophage response, both in size and activity, was also observed when mice were immunized with the nanoparticle formulation. The response was highly specific for the antigen, as the increase in interaction between macrophages and lymphocytes as well as lymphocyte proliferation took place only when they were re-stimulated with recombinant green fluorescence protein (rGFP). Thus the nanoparticle formulation elicited both humoral as well as cellular responses. Cytokine profiling revealed the induction of Th-1 type responses. The results suggest DNA-encapsulated magnesium phosphate (MgPi) nanoparticles may constitute a safer, more stable and cost-efficient DNA vaccine formulation.

Drug targeting using solid lipid nanoparticles

The present review aims to show the features of solid lipid nanoparticles (SLNs) which are at the forefront of the rapidly developing field of nanotechnology with several potential applications in drug delivery and research. Because of some unique features of SLNs such as their unique size dependent properties it offers possibility to develop new therapeutics. A common denominator of all these SLN-based platforms is to deliver drugs into specific tissues or cells in a pathological setting with minimal adverse effects on bystander cells. SLNs are capable to incorporate drugs into nanocarriers which lead to a new prototype in drug delivery which maybe used for drug targeting. Hence solid lipid nanoparticles hold great promise for reaching the goal of controlled and site specific drug delivery and hence attracted wide attention of researchers. This review presents a broad treatment of targeted solid lipid nanoparticles discussing their types such as antibody SLN, magnetic SLN, pH sensitive SLN and cationic SLN.

Charge-mediated topical delivery of plasmid DNA with cationic lipid nanoparticles to the skin

Cationic lipid nanoparticles (cLNs) were modified to develop a gene delivery system for topical use via a dermal route. The cLNs were formulated using high pressure homogenization method and were composed of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), dioleoylphosphatidylethanolamine (DOPE), Tween 20, and tricaprin as a solid core (1:1:1:1.67, w/w). The prepared cLNs were nanoscale-sized (<100 nm) and were highly positive (51 mV). The cLN/DNA complexes demonstrated enhanced transfection potential in the cells at the optimal ratio without cytotoxic effects. To evaluate its efficacy in topical application, in vitro skin transfer of the cLN/DNA complexes was monitored using the measurement of the surface zeta potential of hairless mouse skin and validated using confocal microscopy of the sectioned skin. The in vivo delivery of plasmid DNA with the cLN formulation was examined using the relative expression levels of mRNA after non-invasive application with the cLN/DNA complexes on hair-removed dorsal skin of mice. The cLNs successfully transferred plasmid DNA to the skin, which was facilitated by the charge-mediated interaction between the cLN/DNA complexes and the skin. These results suggest the promising potential of cLNs as a topical gene delivery system for gene vaccine delivery and cutaneous gene therapy in preclinical and clinical applications.