Doxorubicin loaded PVA coated iron oxide nanoparticles for targeted drug delivery

Magnetic drug targeting is a drug delivery system that can be used in locoregional cancer treatment. Coated magnetic particles, called carriers, are very useful for delivering chemotherapeutic drugs. Magnetic carriers were synthesized by coprecipitation of iron oxide followed by coating with polyvinyl alcohol (PVA). Characterization was carried out using X-ray diffraction, TEM, TGA, FTIR and VSM techniques. The magnetic core of the carriers was magnetite (Fe₃O₄), with average size of 10 nm. The room temperature VSM measurements showed that magnetic particles were superparamagnetic. The amount of PVA bound to the iron oxide nanoparticles were estimated by thermogravimetric analysis (TGA) and the attachment of PVA to the iron oxide nanoparticles was confirmed by FTIR analysis. Doxorubicin (DOX) drug loading and release profiles of PVA coated iron oxide nanoparticles showed that up to 45% of adsorbed drug was released in 80 h, the drug release followed the Fickian diffusion-controlled process. The binding of DOX to the PVA was confirmed by FTIR analysis. The present findings show that DOX loaded PVA coated iron oxide nanoparticles are promising for magnetically targeted drug delivery.     

A biocompatible approach to surface modification: Biodegradable polymer functionalized super-paramagnetic iron oxide nanoparticles

In the study, Fe₃O₄ nanoparticles with a size range of 10–20 nm were firstly prepared by the modified controlled chemical coprecipitation method from the solution of ferrous/ferric mixed salt-solution in alkaline medium. Then, the super-paramagnetic iron oxide nanoparticles were covalently modified by biodegradable polymers such as polyethylene glycol (PEG) and poly(ethylene glycol)-co-poly(d,l-lactide) (PELA). The size and its distribution of the nanoparticles were determined by dynamic light scattering measurements (DLS). The magnetic nanoparticles was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), Fourier transform infrared spectroscopy (FT-IR) and UV–visible spectrophotometry (UV). Magnetic properties were measured using a vibrating sample magnetometer. And the 5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT) assay was performed to evaluate the biocompatibility of the magnetic nanoparticles. The results showed that the Fe₃O₄ nanoparticles functionalized by PEG and PELA possessed a mean size of 43.2 and 79.3 nm, respectively, and exhibited an excellent biocompatibility.     

Synthesis of nanocrystalline GaN from Ga2O3 nanoparticles derived from salt-assisted spray pyrolysis

Gallium nitride (GaN) nanoparticles were successfully produced from nano-sized gallium oxide (Ga₂O₃) particles under a flow of ammonia gas. The gallium oxide nanoparticles were prepared by salt-assisted spray pyrolysis (SASP). Highly crystalline Ga₂O₃ nanoparticles with an average diameter of approximately 10 nm were obtained at various temperatures when a flux salt (LiCl, 5 mol/l) was added to the precursor solution. The effects of the crystallinity of the Ga₂O₃ particles and nitridation time on transformation to GaN were characterized using X-ray diffraction and scanning/transmission electron microscopy. Highly crystalline GaN nanoparticles with a mean size of 23.4 nm and a geometric standard deviation of 1.68 nm were obtained when Ga₂O₃ nanoparticles with relatively low crystallinity were used as the starting material. The resulting GaN nanoparticles showed a photoluminescence peak at 364 nm under UV excitation at 254 nm.     

Thermal stability of silica-coated magnetite nanoparticles prepared by an electrochemical method

Magnetite nanoparticles have been prepared by electrooxidation of iron in water. Surface modifications have been conducted by coating the nanoparticles with silica by a one-step synthesis in dilute sodium silicate solution. The mean size of particles was approximately 10–30 nm for the uncoated particles and 9–12 nm for the coated particles. The results obtained from thermal gravimetric/differential thermal analysis (TG/DTA) revealed that the silica layer formed by the electrochemical method was stable and could serve as a protective layer. Annealing the nanoparticles at 550 °C for 30 min converts magnetite into maghemite for the silica-coated particles, and it further converts the uncoated particles into hematite. The conversions cause the saturation magnetization to decrease for all samples.     

Encapsulation of superparamagnetic iron oxide nanoparticles in poly-(lactide-co-glycolic acid) microspheres for biomedical applications

Magnetic microspheres were prepared using a single step coaxial electrohydrodynamic atomization technique at ambient temperature and pressure, with poly(lactic-co-glycolic acid) as the coating and iron oxide (Fe₃O₄) nanoparticles dispersed in polyethylene glycol as the encapsulated material. The morphology and particle size distributions of the prepared magnetic microspheres were investigated by scanning electron microscopy. The particles were spherical with mean diameters ranging from ~ 2 μm to 18 μm, depending on the combination of processing parameters (flow rate and applied voltage). Analysis by infrared spectroscopy and focused ion-beam sectioning confirmed incorporation of iron oxide nanoparticles into the microspheres and the prepared samples were shown to be responsive to an applied magnetic field. This study demonstrates a convenient method for the preparation of nanoparticle loaded microspheres, which could be used potentially as transverse relaxation contrast agents in magnetic resonance imaging, as well as for magnetically guided drug delivery.     

Microwave-assisted hydrothermal synthesis of zinc oxide particles starting from chloride precursor

Zinc oxide (ZnO) was synthesized using a microwave assisted hydrothermal (MAH) process based on chloride/urea/water solution and under 800 W irradiation for 5 min. In the bath, Zn²⁺ ions reacted with the complex carbonate and hydroxide ions to form zinc carbonate hydroxide hydrate (Zn₄CO₃(OH)₆·H₂O), and the conversion from Zn₄CO₃(OH)₆·H₂O to ZnO was synchronously achieved by a MAH process. The as-prepared ZnO has a sponge-like morphology. However, the initial sponge-like morphology of ZnO could change to a net-like structure after thermal treatment, and compact nano-scale ZnO particles were finally obtained when the period of thermal treatment increased to 30 min. Pure ZnO nanoparticles was obtained from calcination of loose sponge-like ZnO particles at 500 °C. The analysis of optical properties of these ZnO nanoparticles showed that the intensity of 393 nm emission increased with the calcination temperature because the defects were reduced and the crystallinity was improved.     

Synthesis of spherical NiO nanoparticles through a novel biosurfactant mediated emulsion technique

Spherical nickel oxide nanoparticles were synthesized by microemulsion technique using rhamnolipids as the surfactant along with n-heptane and water. Nickel hydroxide (Ni(OH)₂) particles were first formed which were then calcined to obtain nickel oxide (NiO) particles. Scanning Electron Microscopy (SEM) studies revealed that the synthesized nickel hydroxide particles were spherical in shape with stacked lamellar sheets. Nickel hydroxide was converted to nickel oxide by calcinations at 600 °C for 3 h and was confirmed by X-ray Diffraction (XRD) analysis. Transmission Electron Microscopy (TEM) showed that the nickel oxide particles were crystalline and of uniform size. The effect of pH on particle size was investigated and it was found that the particle size decreased from 86 ± 8 nm at pH 11.6 to 47 ± 5 nm at pH 12.5. A novel method using rhamnolipid biosurfactant for microemulsion synthesis has been demonstrated which offers an eco-friendly alternative to conventional microemulsion technique based on organic surfactants.     

Poly(furfuryl alcohol)-assisted pyrolysis synthesis of ceramic nanoparticles for solid oxide fuel cells

A pyrolysis synthesis method was developed to prepare ceramic nanoparticles for the fabrication of solid oxide fuel cells. Furfuryl alcohol was used as a polymerizable solvent to dissolve metal nitrates and then polymerized into poly(furfuryl alcohol) (PFA). During the pyrolysis at 600 °C, a mixture of nitrates/PFA was converted into ceramic nanoparticles/carbon networks nanocomposite, and the carbon networks act as a barrier to prevent the aggregation of newly formed nanoparticles during particle crystallization. Dispersible nanoparticles with particle sizes ranging from 40 nm to 200 nm were obtained after burning off carbon networks in air. As an example, Ce_0.8Sm_0.2O_1.9 nanoparticles were synthesized to prepare solid oxide fuel cells, and the fuel cells achieved maximum power densities of 444.5, 625.5 and 684 mW cm^?2 at 500 °C, 550 °C and 600 °C, respectively. Our study shows that the pyrolysis synthesis method described here is promising for the effective synthesis of high quality ceramic nanoparticles.     

Synthesis and characterization of the iron oxide magnetic particles coated with chitosan biopolymer

Magnetic particles are extremely interesting for several biomedical applications; amongst these are therapeutic applications, such as: hyperthermia and release of drugs. The use of magnetic particles to induce hyperthermia in biological tissues is an important factor in cancer therapy. The aim of this study was to prepare and characterize iron oxide magnetic particles coated with biopolymer chitosan, and also to produce ferrofluids from the magnetic particles. The iron oxide magnetic particles (IOMP) were coated with chitosan (CS) by spray-drying method using two IOMP/coating ratios (IOMP/CS = 1.6 and IOMP/CS = 4.5). The magnetic particles were characterized by way of scanning electronic microscopy and energy-dispersive X-ray. The analysis by energy-dispersive X-ray was carried out to determine the chemical composition of particles in samples. The size distribution the iron oxide magnetic particles uncoated and coated were evaluated by the laser diffraction analysis and image analysis, respectively. Amongst the prepared ferrofluids, the sample IOMP/CS = 1.6 proved to be the one that has brought about the best results in therapeutics applications, such as in hyperthermia treatment. This sample was placed within an alternating magnetic field during 40 min, it was observed that 1 °C heated in 3 min and underwent a temperature variation of 7 °C, since it varied from 25 °C to 32 °C. Considering that the experiment would be carried out at body temperature 37 °C, probably, the temperature variation would be very close to the one reported at 25 °C. In such a way, the cancerous cells would reach 44–45 °C and at such temperatures the cancer cells generally perish.     

Encapsulation of Ellipticine in poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) based nanoparticles and its in vitro application

Biodegradable, biocompatible, renewable and non-toxic polyhydroxyalkanoates (PHAs) based nanoparticles are the novel nanotherapeutic tool which are used for the encapsulation of antineoplastic drugs for cancer therapy. In this study, poly-3-hydroxybutyrate-co-5 mol% 3-hydroxyvalerate (PHBV-S), poly-3-hydroxybutyrate-co-11 mol% 3-hydroxyvalerate (PHBV-11) and poly-3-hydroxybutyrate-co-15 mol% 3-hydroxyvalerate (PHBV-15) were used as a nanocarrier for encapsulation of Ellipticine (EPT). EPT is a model anticancer drug. Physicochemical characteristics such as particle size, its morphology and zeta potential of blank and EPT loaded PHBV-S, PHBV-11 and PHBV-15 nanoparticles were studied. In vitro cytotoxicity tests confirmed that the blank PHBV-S, PHBV-11 and PHBV-15 nanoparticles were demonstrating significant biocompatibility without affecting the survival of cancer cell line A549. The loading efficiency of EPT in PHBV nanoparticles was observed in the range of 39.32 to 45.65%. The % inhibition of cancer cell line A549 ranged from 64.28 to 67.77% in comparison to EPT alone in which % inhibition found to be ≤ 45.11%. The IC50 value for each of three different formulations of EPT loaded PHBV nanoparticles ranged from 1.00 to 1.31 μg/mL. The order of % inhibition of cancer cell line A549 for drug loaded nanoparticles was EPT-PHBV-15 > EPT-PHBV-S > EPT-PHBV-11. This system had demonstrated a great potential to increase the cytotoxic effect of EPT by increasing its bioavailability.     

Polypyrrole–titanium(IV) doped iron(III) oxide nanocomposites: Synthesis,characterization with tunable electrical and electrochemical properties

Titanium(IV)-doped synthetic nanostructured iron(III) oxide (NITO) and polypyrrole (PPy) nanocomposites was fabricated by in situ polymerization using FeCl₃ as initiator. The polymer nanocomposites (PNCs) and pure NITO were characterized by X-ray diffraction, Föurier transform infrared spectroscopy, scanning electron microscopy, electron dispersive X-ray spectroscopy, transmission electron microscopy, etc. Thermo gravimetric and differential thermal analyses showed the enhancement of thermal stability of PNCs than the pure polymer. Electrical conductivity of the PNCs had increased significantly from 0.793 × 10^?2 S/cm to 0.450 S/cm with respect to the PPy, and that had been explained by 3-dimensional variable range hopping (VRH) conduction mechanisms. In addition, the specific capacitance of PNCs had increased from 147 F/g to 176 F/g with increasing NITO content than that of pure NITO (26 F/g), presumably due to the growing of mesoporous structure with increasing NITO content in PNCs which reduced the charge transfer resistance significantly.     

Synthesis of hydroxyapatite crystals using carboxymethyl inulin for use as a delivery of ibuprofen

In the present study biodegradable, environmentally friendly polysaccharide-based polycarboxylate, carboxymethyl inulin (CMI), was used to produce hydroxyapatite (HAP) particles by wet chemical synthesis under controlled temperature, pH, and atmospheric conditions. The morphology and microstructure of the HAP nanoparticles were investigated by XRD, SEM, DTA–TGA and FTIR. CMI affects morphology, surface area, dimension and particle size distribution of the crystals. The reduction in size is greater in the direction of the c-axis. The increase in the polymer concentration to 7.5 g/L resulted in the mixture of nanoparticles with particle sizes of less than 100 nm. The SEM micrograph shows the formation of well-crystallized, agglomerated small particles of HAP. X-ray analysis has shown that the resulting particles have high thermal stability.The obtained crystals were used to produce tablets by direct compression of HAP. The influence of sample's CMI concentration on drug release profiles was investigated by using ibuprofen (C₁₃H₁₈O₂) as a model drug. The model was used to determine the effective diffusion coefficient of the drug from the tablets. A good agreement between experimental data and model predictions was obtained as calculated in the present work. The values of the diffusion coefficients range from 1.62 × 10^? 7 to 4.72 × 10^? 7 m² h^? 1.     

Polymer-directed large-scale synthesis of single-crystal vanadium oxide nanobelts

Large-scale single crystalline vanadium oxide nanobelts were synthesized by hydrothermal treatment of NH₄VO₃ in the presence of polymer PEG-4000 at 180 °C for 24 h. Techniques of SEM, TEM, XRD, FT-IR, HRTEM, and SAED were used to characterize the morphology, composition and structure of the as-obtained nanobelts. The as-prepared vanadium oxide nanobelts are up to several hundreds micrometers in length, 100 nm–1 μm in width, 20–30 nm in thickness, and grow along the [1 0 0] direction. PEG plays a critical role for the formation of the vanadium oxide nanobelts in the present synthetic system. A preliminary formation mechanism was proposed to account for the formation of the as-obtained nanobelts.     

Effect of polymer modifier chain length on thermal conductive property of polyamide 6/graphene nanocomposites

The influence of polymer modifier chain length on the thermal conductivity of polyamide 6/graphene (GA) nanocomposites, including through-plane (λ_z) and in-plane (λ_x) directions were investigated. Here, three chain lengths of double amino-terminated polyethylene glycol (NH₂–PEG–NH₂) were used to covalently functionalize graphene with graphene content of 5.0 wt%. Results showed that λ_z was enhanced with the chain length of NH₂–PEG–NH₂ increased, but λ_x reached a maximum value at a certain chain length of NH₂–PEG–NH₂. The maximum λ_z and λ_x of GA are 0.406 W m⁻¹ K⁻¹ and 9.710 W m⁻¹ K⁻¹, respectively. This study serves as a foundation for further research on the thermal conductive property of graphene nanocomposites using different chain lengths of polymer modifier to improve the λ_z and λ_x of the thermal conductive materials.     

Adsorption of collagen to indium oxide nanoparticles and infrared emissivity study thereon

Adsorption of collagen to indium oxide nanoparticles was carried out in water–acetone solution at volumetric ratio of 1:1 with pH value varying from 3.2 to 9.3. As indicated by TGA, maximum collagen adsorption to indium oxide nanoparticles occurred at pH of 3.2. It was proposed that noncovalent interactions such as hydrogen bonding, hydrophilic and electrostatic interactions made main contributions to collagen adsorption. The IR emissivity values (8–14 μm) of collagen-adsorbed indium oxide nanoparticles decreased significantly compared to either pure collagen or indium oxide nanoparticles possibly due to the interfacial interactions between collagen and indium oxide nanoparticles. And the lowest infrared emissivity value of 0.587 was obtained at collagen adsorption of 1.94 g/100 g In₂O₃. On the chance of improved compatibility with organic adhesives, the chemical activity of adsorbed collagen was further confirmed by grafting copolymerization with methyl methacrylate by formation of polymer shell outside, as evidenced by IR spectrum and transmission electron microscopy.     

In vitro studies of magnetically enhanced transfection in COS-7 cells

In the magnetically enhanced gene delivery technique, DNA complexed with polymer coated aggregated magnetic nanoparticles (AMNPs) is used for effecting transfection. The aim of this study is to examine the relationship between transfection efficiency and the physical characteristics of the polymer coated AMNPs. In vitro studies of transfection efficiency in COS-7 cells were carried out using pEGFP-N1 and pMIR-REPORT complexed polyethylenimine (PEI) coated iron oxide magnetic nanoparticles. PEI coated AMNPs (PEI-AMNPs) with average individual particle diameters in the range of 8 nm to 30 nm were studied and characterized by transmission electron microscopy, vibrating sample magnetometry, X-ray diffractometry, thermal gravimetric analysis and photon correlation spectroscopy methods. PEI-A8MNP and PEI-A30MNP yielded higher transfection efficiency compared to commercial polyMAG particles as well as PEI of equivalent molar ratio of nitrogen/phosphorous (N/P ratio). The transfection efficiency was related to the physical characteristics of the PEI-AMNPs and its complexes: transfection efficiency was strongly positively correlated with saturation magnetization (Ms) and susceptibility (χ), strongly negatively correlated with N/P ratio, moderately positively correlated to zeta potential and moderately negatively correlated to hydrodynamic diameter of the complex. PEI-A8MNP and PEI-A30MNP possessing higher Ms, χ, lower N/P ratio and smaller complex size exhibited higher transfection efficiency compared to PEI-A16MNP which have weaker magnetic properties, higher N/P ratio and larger complex size. We have demonstrated that optimization of the physical properties of PEI-AMNPs is needed to maximize transfection efficiency.     

The influence of preparation conditions on ZrO2 nanoparticles with different PEG–PPG–PEG surfactants by statistical experimental design

In this study mesoporous Zirconia powder with high surface area was prepared by using PEG–PPG–PEG new block copolymer as the non-ionic surfactant. The preparation conditions were optimized by Taguchi method of experimental design and Minitab Software to synthesize high surface area tetragonal-ZrO₂ nanoparticles. The BET surface area of powders was 114–175 m²/gr and the particles size calculated by Deby–Sherrer equation was 5–9 nm. pH = 11, aging time 38 h, Zr molarity 0.03, Surfactant/Zr mole ratio 0.04 and molecular weight 8400 were the best conditions to manufacture ZrO₂ with higher surface area. The sample prepared under optimized conditions was compared to that synthesized by PEG surfactant. XRD patterns of two ZrO₂ samples, hysteresis loop, pore size distribution, BET surface area and SEM results are similar.     

Apatite-forming ability and magnetic properties of glass-ceramics containing zinc ferrite and calcium sodium phosphate phases

Fine particles of zinc ferrite (ZnFe₂O₄) and calcium sodium phosphate [NaCaPO₄] were crystallized in bulk x(ZnO, Fe₂O₃)(65?x)SiO₂20(CaO, P₂O₅)15Na₂O (6 ≤ x ≤ 21 mol %) glassy matrix by heat treatment. Initial magnetization curves reveal that samples with x = 6 and 9 mol % zinc–iron oxide exhibit both ferrimagnetic and paramagnetic contributions, whereas, samples with x > 9 mol % zinc–iron oxide exhibit only ferrimagnetic contribution. This observation is supported by the disappearance of the electron paramagnetic resonance (EPR) absorption line centered at g ≈ 4.3 in samples with x > 9 mol % zinc–iron oxide. Apatite-forming ability of the glass-ceramic samples was investigated by examining apatite formation on the surface of the samples treated in simulated body fluid (SBF). Increase in apatite-forming ability was observed with an increase in zinc–iron oxide content. The results obtained have been used to understand the evolution of the apatite surface layer as a function of immersion time in SBF and glass-ceramic composition. A good correlation has also been observed between the magnetic nature of the samples and their apatite-forming ability. These materials are expected to find application as thermo-seeds in hyperthermia treatment of bone cancer.     

Synthesis and characterization of MFe2O4 (M = Mg,Mn, Ni) nanoparticles

MFe₂O₄ nanoparticles were obtained in the presence of natural compounds as carboxymethylcellulose (CMC). The CMC polymer had a double function as a capping agent and as a protecting agent in the growth process of nanoparticles. The synthesized nanoparticles were characterized using thermal analysis (TG, DTA, DTG), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and a vibrating sample magnetometer (VSM). The XRD patterns indicate that all the samples were formed in single phase spinel structure. The results also show that the samples calcinated at 500 °C for 6 h have the best crystallinity and the calculated crystallite size was in the range of 6–13 nm. The thermal analysis and FTIR spectra indicate a core–shell structure of the MFe₂O₄ nanoparticles obtained.     

Combustion characteristics of the heat pellet prepared from the Fe powders obtained by spray pyrolysis

Fe powders for thermal batteries were prepared by reduction of iron oxide powders obtained by spray pyrolysis. The iron oxide powders prepared by spray pyrolysis had fine size, spherical shape and high surface area. The morphologies of the Fe powders were affected by the preparation temperatures of the iron oxide powders. The Fe powders obtained from the iron oxide powders prepared by spray pyrolysis at 900 and 1000 °C had slightly aggregated structure of the primary powders with several microns sizes. The powders had pure Fe phases at reducing temperatures between 600 and 800 °C. The heat pellets with diameter of 18.2 mm were prepared using Fe powders and potassium perchlorate (KClO₄). The porosity of the prepared heat pellet was about 40%. The break strength of the heat pellet was 0.9 kgf. The ignition sensitivity of the heat pellet was 4 W. The maximum burn rate of the heat pellet obtained from the Fe powders were 8.6 cm s^?1.