Cationic poly(lactide-co-glycolide) nanoparticles as efficient in vivo gene transfection agents

Poly(lactide-co-glycolide) (PLGA), a biocompatible and biodegradable polyester co-polymer of PLA and PGA, has been recognized for its ability to deliver genes. However, gene delivery by PLGA nanoparticles is limited by their negative charge and their poor transport through mucosal barriers. In this study, PLGA nanoparticles were surface modified with cationic chitosan in an effort to improve their gene delivery capability. PLGA nanoparticles were synthesized by emulsion-diffusion-evaporation technique using PVA-chitosan (PLGA1) or PVA-chitosan-PEG (PLGA2) blend as stabilizers. This method is reproducible and produces nanoparticles with hydrodynamic diameter <200 nm. The nanoparticles were characterized by zetasizer, photon correlation spectroscopy and atomic force microscopy. A549 epithelial cells were transfected in vitro with PLGA particles complexed with a reporter plasmid encoding green fluorescent protein. PLGA particles transferred EGFP gene, but were less efficient than the lipofectamine control. The nanoparticles were also tested for their ability to transport across the nasal mucosa in vivo in mice. The results show that both PLGA1 and PLGA2 facilitate gene delivery and expression in vivo with increased efficiency and without causing inflammation, as measured by IL-6. Together, these results indicate that chitosan-modified PLGA nanoparticles have greater potential as gene carriers.     

In vitro and in vivo evaluation of puerarin-loaded PEGylated mesoporous silica nanoparticles

Puerarin, which is extracted from Chinese medicine, is widely used in China and mainly used as a therapeutic agent for the treatment of cardiovascular diseases. Owing to its short elimination half-life in human beings, frequently intravenous administration of high doses of puerarin may be needed, which possibly leads to severe and acute side effects. The development of an effective sustained-release drug delivery system is urgently needed. In this study, PEGylated mesoporous silica nanoparticles (PEG-MSNs) had become a preferred way to prolong the half-life and improve the bioavailability of drugs. The release of puerarin from PEG-MSNs was pH dependent, and the release rate was much faster at lower pH than that at higher pH. Moreover, the PEG-MSNs exhibited improved blood compatibility over the MSNs in terms of low hemolysis, and it could also reduce the side effect of hemolysis induced by PUE. Compared with puerarin, PUE-loaded PEG-MSNs showed a 2.3-fold increase in half-life of puerarin and a 1.47-fold increase in bioavailability. Thus, the PEG-MSNs hold the substantial potential to be further developed as an effective sustained-release drug delivery system.     

Perylene-labeled silica nanoparticles: synthesis and characterization of three novel silica nanoparticle species for live-cell imaging

The increasing exposure of humans to nanoscaled particles requires well-defined systems that enable the investigation of the toxicity of nanoparticles on the cellular level. To facilitate this, surface-labeled silica nanoparticles, nanoparticles with a labeled core and a silica shell, and a labeled nanoparticle network-all designed for live-cell imaging-are synthesized. The nanoparticles are functionalized with perylene derivatives. For this purpose, two different perylene species containing one or two reactive silica functionalities are prepared. The nanoparticles are studied by transmission electron microscopy, widefield and confocal fluorescence microscopy, as well as by fluorescence spectroscopy in combination with fluorescence anisotropy, in order to characterize the size and morphology of the nanoparticles and to prove the success and homogeneity of the labeling. Using spinning-disc confocal measurements, silica nanoparticles are demonstrated to be taken up by HeLa cells, and they are clearly detectable inside the cytoplasm of the cells.     

Synthesis, characterization and transfection of a novel folate-targeted multipolymeric nanoparticles for gene delivery

Novel folate-conjugated biodegradable multipolymeric nanoparticles (NPs) were constructed and evaluated for potential use in gene delivery to human cervical carcinomas Hela cells, which overexpressed folate receptors. Folate-poly(ethylene glycol)-poly(d, l-lactic-co-glycolic acid) (PELGA-F) was synthesized and collaborated with poly-l-lysine (PLL) to form polymer-polycationic peptide-DNA (PPD) NPs. Fluorescein sodium and polylysine-condensed DNA (PD) were encapsulated in both PELGA nanoparticles (PELGA-NPs) and folate modified nanoparticles (PELGA-F-NPs), which were prepared by a modified solvent extraction/evaporation method. Effects of the folate conjugation and PLL introduction on the uptake of NPs was qualified by fluorescent invert microscopy and quantified by spectrofluorometric measurement, while effect on the gene expression was measured by X-gal staining and luciferase assay, both using Hela cells as an in vitro model. Results showed that cellular uptake of NPs was enhanced by folate modification, but had no difference after PLL encapsulation. In transfection tests, increased gene expression also confirmed the different functions of folate and PLL introduction. It is feasible that folate-linked multipolymeric NPs should be an efficient targeted carrier for gene delivery.     

Preparation and in vitro/in vivo evaluation of gliclazide loaded Eudragit nanoparticles as a sustained release carriers

The aim of this study was to formulate and optimize gliclazide-loaded Eudragit nanoparticles (Eudragit L100 and Eudragit RS) as a sustained release carrier with enhanced efficacy. Eudragit L 100 nanoparticles (ELNP) were prepared by controlled precipitation method whereas Eudragit RSPO nanoparticles (ERSNP) were prepared by solvent evaporation method. The influence of various formulation factors (stirring speed, drug:polymer ratio, homogenization, and addition of surfactants) on particle size, drug loading, and encapsulation efficiency were investigated. The developed Eudragit nanoparticles (L100 and RS) showed high drug loading and encapsulation efficiencies with nanosize. Mean particle size altered by changing the drug:polymer ratio and stirring speed. Addition of surfactants showed a promise to increase drug loading, encapsulation efficiency, and decreased particle size of ELNP as well as ERSNP. Dissolution study revealed sustained release of gliclazide from Eudragit L100 as well as Eudragit RSPO NP. SEM study revealed spherical morphology of the developed Eudragit (L100 and RS) NP. FT-IR and DSC studies showed no interaction of gliclazide with polymers. Stability studies revealed that the gliclazide-loaded nanoparticles were stable at the end of 6 months. Developed Eudragit NPs revealed a decreased t_min (ELNP), and enhanced bioavailability and sustained activity (ELNP and ERSNP) and hence superior activity as compared to plain gliclazide in streptozotocin induced diabetic rat model and glucose-loaded diabetic rat model. The developed Eudragit (L100 and RSPO) NP could reduce dose frequency, decrease side effects, and improve patient compliance.     

Novel photothermal-responsive sandwich-structured mesoporous silica nanoparticles: synthesis,characterization, and application for controlled drug delivery

Novel thermal nanoparticles [hollow mesoporous silica nanospheres (HMSNs)–poly (N-isopropyl acrylamide-acrylic acid) PNIPAM-AA] were developed with Ag nanoparticles (AgNps) as the core, mesoporous silica nanoparticles as the layer, and thermally responsive polymers PNIPAM-AA as the shell. The AgNps had good photothermal effects, PNIPAM-AA was responsive to temperature, the combination of AgNps and PNIPAM-AA could be used as a photothermal-responsive switch for drug release, and HMSNs greatly increased the drug loading of the carrier. The samples were characterized by means of scanning electron microscopy, transmission electron microscopy, N₂ adsorption–desorption, thermogravimetric analysis, Fourier transform infrared spectroscopy, and UV–Vis absorption spectra. The results showed that Ag@HMSN nanoparticles possessed a uniform diameter (330 nm), high specific surface area (822.45 m²/g), and mesoporous pore size (2.75 nm). Using ibuprofen (IBU) as a model drug, the release process was monitored under in vitro conditions to investigate its release characteristics at different temperatures. The results showed that the nanoparticles had a significant regulatory effect on IBU release.

Graphical abstract

     

Synthesis and characterization of bicalutamide-loaded magnetic nanoparticles as anti-tumor drug carriers

This study examined the optical characteristics of bicalutamide-loaded magnetic/ethylene glycol composite nanoparticles (BMP), as well as their anti-cancer activity against cancer cells. The gamma-Fe2O3 magnetic nanoparticles (MNPs), approximately 20 nm in diameter, were prepared via a chemical co-precipitation method and coated with two surfactants to yield a water-based product. The characteristics of the particles were determined via X-ray diffraction (XRD), field emission scanning electron microscopy, and Raman spectrophotometry. The Raman spectra of the BMP showed peaks at 222, 283, 395, 520, 669 and 1316 cm(-1), with broadened band in comparison to the Raman spectra of the magnetic nanoparticles. The BMP absorbance evidenced a rapid increase, with a broad peak at 409 nm, thus reflecting a good loading of the bicalutamide onto the magnetic nanoparticles. The results of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the MNPs were non-toxic against human brain cancer cells (SH-SY5Y), human cervical cancer cells (Hela), human liver cancer cells (HepG2), breast cancer cells (MCF-7), colon cancer cells (CaCO2) and human prostate cancers (Du 145, PC3) tested herein. In particular, BMPs were cytotoxic at 56% against DU145 cells, at 74.37% in SH-SY5Y cells, and at 58% in Hela cells. Our results demonstrated the biological applicability of BMP nanoparticles as anticancer agents and as agents for enhanced drug delivery against human prostate cancer cells. Our results indicated that the MNPs were biostable and that the BMP functioned effectively as drug delivery vehicles.     

Calcium carbonate nanoparticles: synthesis, characterization and biocompatibility

The synthesis of nanoparticles and their functionalization to effectively utilize them in biological applications including drug delivery is currently a challenge. Calcium carbonate among many other inorganic nanosized particles offers promising results for such applications. We have synthesized calcium carbonate nanoparticles using polymer mediated growth technique, where one of the ions bound within polymer matrix and the other diffuses and reacts to form desired compound. The synthesized nanoparticles are characterized using X-ray diffraction, Scanning Electron Microscopy and spectroscopic techniques such as Fourier-Transform Infra-red spectroscopy and UV-Vis spectroscopy. The diameter of the calcium carbonate nanoparticles is estimated to be 39.8 nm and their biocompatibility studies showed no significant induction of oxidative stress or cell death even at higher concentrations (50 microg) upon exposure to HeLa and LE cells. Here, we report that the synthesized calcium carbonate nanosized particles using polymer mediated growth technique are biocompatible and can be safely used for biomedical applications.     

寡胺-葡聚糖类阳离子化合物合成及其在基因转染中的应用

应用氧化葡聚糖与精胺通过还原胺法反应,制备了聚阳离子非病毒基因载体葡聚糖-寡胺化合物;用红外光谱测定仪、核磁共振波谱仪、紫外光谱仪,激光纳米粒度测定仪、透射电子显微镜进行了表征.证实了该载体为葡聚糖-精胺化合物DSP.其平均粒径为170nm,Zeta电位为+31.1mV,镜下呈园球形状.将载体DSP与pCMV-GFP的质粒DNA以8:1(N/P)组成复合物时,对SMMC-7721人肝癌细胞进行体外转染,转染效率高于阳性对照组transfectine 2000,为31.1%.实验表明该材料有望成为临床的非病毒基因载体.     

Porous hollow silica nanoparticles as carriers for controlled delivery of ibuprofen to small intestine

With two different methods, ibuprofen was entrapped into porous hollow silica nanoparticles (PHSNs) carriers, which were synthesized through a sol-gel route by using CaCO3 nanoparticles as the inorganic templates. By employing pressured CO2 as the loading medium, the amount of ibuprofen that was pressed into the carriers was approximately 52% higher than that by simply soaking. The drug release behaviors of the ibuprofen-loaded PHSNs were investigated in a simulated intestine juice and an artificial gastric fluid, respectively, and it demonstrated a sustained release pattern in all cases and the sample prepared under high pressure had a lower release rate in both fluids and thus owned a greater sustained drug release capacity. In the acidic artificial gastric fluid, no silica was degraded and only 16% of the loaded ibuprofen was released from the matrix in 300 min. However, much more silica was degraded in the simulated intestine juice in a shorter time and almost all the loaded ibuprofen was dissolved into the solution eventually, resulting in a quicker and complete ibuprofen release. Therefore, the PHSNs can be utilized for applications of controlled drug delivery to small intestine.     

Synthesis, characterization, and biological applications of multifluorescent silica nanoparticles

Multifluorescent silica nanoparticles were synthesized by the St?ber method using conjugates of (3-aminopropyl)triethoxysilane and fluorescent dye-N-hydroxysuccinimide esters. The nanoparticles containing the fluorescent dyes were well dispersed and showed high, stable, and tunable fluorescence intensities. In addition, we prepared multifluorescent silica nanoparticles containing two kinds of fluorescent dyes and used the nanoparticles in biological applications. Flow cytometry analysis showed high and tuned fluorescence and multiple fluorescences from single nanoparticles with diameters of approximately 400 nm. Fluorescence microscopy analysis also showed high and tuned fluorescence, as well as multiple fluorescences from single nanoparticles and from cells labeled with multifluorescent silica nanoparticles. The intracellular distribution of nanoparticles was evaluated by confocal microscopy and electron microscopy. We discuss the advantages and demonstrate the usefulness of our nanoparticles in relation to commercially available fluorescent nanoparticles including quantum dots.     

Superparamagnetic iron oxide nanoparticles (SPIONs): from synthesis to in vivo studies--a summary of the synthesis, characterization, in vitro, and in vivo investigations of SPIONs with particular focus on surface and colloidal properties

In this work, we present a short summary of the synthesis and characterization of superparamagnetic iron oxide nanoparticles and their behavior in vitro and in vivo. Therefore, we have used various characterization techniques to deduce the physical particle size as well as magnetic properties. It is shown that the particle properties were significantly improved by a thermochemical treatment and dialysis, obtaining weakly interacting particles with a clear blocking temperature. We also present the interaction of polyvinyl alcohol and vinyl alcohol/vinyl amine copolymer-coated SPIONs with HELA cells. It is shown that the uptake increased significantly in the presence of a magnetic field and that surface functional groups had an impact on particle uptake and metabolic activity. Furthermore, the influences of the varied parameters (polymer type and therefore surface charge, cell medium, and serum) on the agglomeration rate and the cell uptake are presented and discussed. Finally, we briefly describe the intraarticular application of SPIONs in sheep, their uptake by synovial membrane, and their systemic distribution and elimination.     

Magnetic nanoparticles as gene delivery agents: enhanced transfection in the presence of oscillating magnet arrays

Magnetic nanoparticle-based gene transfection has been shown to be effective in combination with both viral vectors and with non-viral agents. In these systems, therapeutic or reporter genes are attached to magnetic nanoparticles which are then focused to the target site/cells via high-field/high-gradient magnets. The technique has been shown to be efficient and rapid for in vitro transfection and compares well with cationic lipid-based reagents, producing good overall transfection levels with lower doses and shorter transfection times. In spite of its potential advantages (particularly for in vivo targeting), the overall transfection levels do not generally exceed those of other non-viral agents. In order to improve the overall transfection levels while maintaining the advantages inherent in this technique, we have developed a novel, oscillating magnet array system which adds lateral motion to the particle/gene complex in order to promote transfection. Experimental results indicate that the system significantly enhances overall in vitro transfection levels in human airway epithelial cells compared to both static field techniques (p<0.005) and the cationic lipids (p<0.001) tested. In addition, it has the previously demonstrated advantages of magnetofection-rapid transfection times and requiring lower levels of DNA than cationic lipid-based transfection agents. This method shows potential for non-viral gene delivery both in vitro and in vivo.     

Biotemplated silica and titania nanowires: synthesis, characterization and potential applications

A simple biotemplating method for the synthesis of silica (SiO2) and titania (TiO2) nanowires was designed on a fibrillar protein (alpha-synuclein) template. The diameter of SiO2 and TiO2 nanowires could be varied, between 20-100 nm, by varying the processing conditions. The nanowires were characterized by energy dispersive spectroscopy (EDS) and electron energy loss spectroscopy (EELS). Due to their high surface area and porosity, the nanowires were tested for potential applications in enzymatic biosensor design.     

Artesunate-loaded chitosan/lecithin nanoparticles: Preparation,characterization, and in vivo studies

Artesunate (AST), the most widely used artemisnin derivative, has poor aqueous solubility and suffers from low oral bioavailability (~40%). Under these conditions, nanoparticles with controlled and sustained released properties can be a suitable solution for improving its biopharmaceuticals properties. This work reports the preparation and characterization of auto-assembled chitosan/lecithin nanoparticles loaded with AST and AST complexed with β-cyclodextrin (β-CD) to boost its antimalarial activity. The nanoparticles prepared by direct injection of lecithin alcoholic solution into chitosan/water solution have shown the particle size distribution below 300?nm. Drug entrapment efficiency was found to be maximum (90%) for nanoparticles containing 100?mg of AST. Transmission electron microscopy images show spherical shape with contrasted corona (chitosan) surrounded by a lipidic core (lecithin + isopropyl myristate). Differential scanning calorimeter thermograms demonstrated the presence of drug in drug-loaded nanoparticles along with the disappearance of decomposition exotherm suggesting the increased physical stability of drug in prepared formulations. Negligible changes in the characteristic peaks of drug in Fourier-transform infrared spectra indicated the absence of any interaction among the various components entrapped in the nanoparticle formulation. In vitro drug release behavior was found to be influenced by pH value. Increased in vivo antimalarial activity in terms of less mean percent parasitemia was observed in infected Plasmodium berghei mice after the oral administration of all the prepared nanoparticle formulations.     

Controllable synthesis,characterization and optical properties of ZnS:Mn nanoparticles as a novel biosensor

To be a suitable biolabeling agent (biosensor), the nanoparticles should have high luminescent efficiency and proper surface groups for coupling with biomolecules. In this article, high-quality ZnS:Mn nanoparticles were synthesized from quaternary W/O micro-emulsion system with different Mn% for detecting the best concentration. The addition of biotin and the subsequent specific binding events alter the dielectric environment of the nanoparticle, resulting in a spectral shift of the particle plasmon resonance. Cyclohexane was used as oil, Triton X-100 as surfactant, n-hexanol as a co-surfactant and mercaptoethanol and thioglycolic acid for the best linking of the biological part to the nanoparticle (as linking agents). Surfactant and co-surfactant produce a stable emulsion with connection to the surface of nanoparticles and prevention from contacting together. For qualitative and quantitative analyses of this product scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), inductive coupled plasma (ICP), zeta meter for measurement ZP and spectrograph techniques are used. The results showed that with reducing particle size, emission shifted to the lower wavelengths. In addition, with conjugation between avidin and biotin by mercaptoethanol in biologic media, spectral emission decreased.     

Flower-shaped gold nanoparticles: synthesis, characterization and their application as SERS-active tags inside living cells

The detection of Raman signals inside living cells is a topic of great interest in the study of cell biology mechanisms and for diagnostic and therapeutic applications. This work presents the synthesis and characterization of flower-shaped gold nanoparticles and demonstrates their applicability as SERS-active tags for cellular spectral detection. The particles were synthesized by a facile, rapid new route that uses ascorbic acid as a reducing agent of gold salt. Two triarylmethane dyes which are widely used as biological stains, namely malachite green oxalate and basic fuchsin, were used as Raman-active molecules and the polymer mPEG-SH as capping material. The as-prepared SERS-active nanoparticles were tested on a human retinal pigment epithelial cell line and found to present a low level of cytotoxicity and high chemical stability together with SERS sensitivity down to picomolar particle concentrations.