Surface Functionalized Iron Oxide Nanoparticles Research Articles

Induction heating induced self-healing of nanocomposites based on surface-functionalized cationic iron oxide particles and polyelectrolytes.

Supramolecular interactions represent versatile, reversible, and intrinsic mechanisms for bond formation after the failure of materials. Ionic interactions excel through high flexibility and binding strength. In this study, ionic interactions between polymer matrices and inorganic nanoparticles were used to induce self-healing properties. Random, anionic polyelectrolyte copolymers consisting of di(ethylene glycol) methyl ether methacrylate and sodium-4-(methacryloyloxy)butan-1-sulfonate were synthesized by atom transfer radical polymerization. Differential scanning calorimetry measurements confirmed the adjustability of the glass transition temperature via the polymer composition. Within the glass transition temperature window of the homopolymers from −23 °C to 126 °C, the range between −18 °C to 50 °C was examined, generating suitable matrices for self-healing. Superparamagnetic iron oxide nanoparticles with a size of 8 nm were synthesized by thermal decomposition of iron(iii) acetylacetonate and used as the inorganic filler. Positive surface charges were introduced by functionalization with N,N,N-trimethyl-6-phosphonhexan-1-aminium bromide. Functionalization was confirmed with FTIR, TGA, and zeta potential measurements. Ionic interactions between filler and polymer promote a uniform particle dispersion within the material. Self-healing experiments were performed at 80 °C and without the addition of further healing agents. Utilizing the magnetic properties induced by the iron oxide nanoparticles, spatially resolved healing within an alternating magnetic field was achieved on a μm scale.

Toxicity of surface functionalized iron oxide nanoparticles toward pure suspension culture and soil microcosm

Surface functionalized iron oxide nanoparticles are increasingly being used in environmental and medical applications, raising concerns on their fate and environmental impact. In this work, Fe3O4 nanoparticles prepared by a chemical co-precipitation method were functionalized with citric acid, polyethylene glycol of molecular weights 6000 and 8000, and methacrylic acid. Resazurin reduction-based nanoparticles toxicity assessment was performed with suspended microbial culture (50–250 mg L−1 NPs) as well as in soil microcosm (250–1250 mg kg−1). Resazurin reduction by freely suspended E. coli cultures in presence of uncoated, citric acid- and PEG-coated nanoparticles was either comparable or higher than that of the nanoparticle free control. However, the toxicity of methacrylic acid coated nanoparticles was evident as resazurin reduction was largely inhibited. Residual resazurin in test sets containing nanoparticle spiked seven days aged sterile soil were 20% to 82% that of freshly spiked control, suggesting significant attenuation of toxicity in soil media. The results obtained from this work may provide a better understanding of the impact of engineered iron-oxide nanoparticles in the soil ecosystem.

Acoustic Sensors Based on Amino-Functionalized Nanoparticles to Detect Volatile Organic Solvents.

Love-wave gas sensors based on surface functionalized iron oxide nanoparticles has been developed in this research. Amino-terminated iron oxide nanoparticles were deposited, by a spin coating technique, onto the surface of Love-wave sensors, as a very reproducible gas-sensing layer. The gases tested were organic solvents, such as butanol, isopropanol, toluene and xylene, for a wide and low concentration range, obtaining great responses, fast response times of a few minutes (the time at which the device produced a signal change equal to 90%), good reproducibilities, and different responses for each detected solvent. The estimated limits of detection obtained have been very low for each detected compound, about 1 ppm for butanol, 12 ppm for isopropanol, 3 ppm for toluene and 0.5 ppm for xylene. Therefore, it is demonstrated that this type of acoustic wave sensor, with surface amino-functionalized nanoparticles, is a good alternative to those ones functionalized with metal nanoparticles, which result very expensive sensors to achieve worse results.

Phenol adsorption on surface-functionalized iron oxide nanoparticles: modeling of the kinetics, isotherm, and mechanism

Phenol adsorption from aqueous solution was carried out using uncoated and methyl acrylic acid (MAA)-coated iron oxide nanoparticles (NPs), having size 0.98). X-ray photoelectron spectroscopy analysis of pristine and phenol-adsorbed NPs revealed core-level binding energy and charge for Fe(2s) and O(1s) on the NP surfaces. The calculations suggest that phenol adsorption onto MAA-coated NPs is a charge transfer process, where the adsorbate (phenol) acts as an electron donor and the NP surface (Fe, O) as an electron acceptor. However, a physisorption process appears to be the relevant mechanism for uncoated NPs.

Novel polyurethane rigid foam/organically modified iron oxide nanocomposites

Magnetic polyurethane rigid foam nanocomposites were synthesized by incorporation of surface functionalized iron oxide nanoparticles with 3‐aminopropyltriethoxysilane (APTS). Magnetite nanoparticles (MNPs) and Fe3O4@APTS were synthesized via co‐precipitation and sol–gel methods, respectively. The main purpose of the surface modification of MNPs was the formation of hydrogen bond between amino groups of Fe3O4@APTS with the urethane groups to improve magnetic and thermal properties of the nanocomposites. The effect of different amounts of Fe3O4@APTS on the thermal and magnetic behavior of resultant nanocomposite was investigated and the optimum percentage of nanostructure in foam formulation was defined. POLYM. COMPOS., 38:877–883, 2017. © 2015 Society of Plastics Engineers

Magnetophoretic separation of microalgae: the role of nanoparticles and polymer binder in harvesting biofuel

Magnetophoretic separation of Chlorella sp. microalgal biomass is proven to be a feasible downstream processing technology for biofuel production. Kinetic study of cells separation in real time reveals the major steps involved for each stage of low gradient magnetic separation (LGMS) with field gradient (∇B) less than 80 T m−1. Transmission and scanning electron microscopy (TEM & SEM) together with Fourier transforms infrared (FTIR) spectra analysis are employed to confirm the full attachment of surface functionalized iron oxide nanoparticles (SF-IONPs) onto microalgal cells and how the particles distributed on the cell's surfaces. From the cross section TEM images of cells, IONPs shown the tendency to be internalized into Chlorella sp. cells but not affect the biofuel quality.

Properties of surface functionalized iron oxide nanoparticles (ferrofluid) conjugated antibody for lateral flow immunoassay application

In this study, colloidal stability of iron oxide nanoparticles (IONPs) with several acid functionalizations and biocompatible polymer coating were compared for use as labelling agent in lateral flow immunoassay (LFIA). IONPs were synthesized using the precipitation method and peptized using perchloric acid (PA), nitric acid (NA) and citric acid (CA) to form a stable IONPs ferrofluid. Steric stabilization of IONPs using silane polyethelene glycol (SiPEG) was developed to improve biocompatibility and provide spaces for subsequent conjugation process. From the transmission electron microscopy (TEM) images, the sizes of IONPs obtained with different acids peptization were in range of 11–17nm. The IONPs peptized using citric acid showed the most stable ferrofluid condition at physiological condition with zeta potential value of −49mV. The LFIA was also developed to examine the conjugation properties of IONPs to mouse anti-human IgG4 antibody (MαHIgG4). IONPs functionalized with citric acid can be directly conjugated with the MαHIgG4 without the need of SiPEG addition. This is due to the presence of the carboxylic group that acted as a ligand to the extended bond formation with the antibody. Moreover, the conjugation of IONPs with MαHIgG4 was also tested in a LFIA to detect brugian filariasis. The conjugated IONPs-CA without SIPEG showed the optimum detection efficiency within 15min of assay time.

Magnetic iron oxide nanoparticles: synthesis and surface functionalization strategies.

Surface functionalized magnetic iron oxide nanoparticles (NPs) are a kind of novel functional materials, which have been widely used in the biotechnology and catalysis. This review focuses on the recent development and various strategies in preparation, structure, and magnetic properties of naked and surface functionalized iron oxide NPs and their corresponding application briefly. In order to implement the practical application, the particles must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of iron oxide NPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The problems and major challenges, along with the directions for the synthesis and surface functionalization of iron oxide NPs, are considered. Finally, some future trends and prospective in these research areas are also discussed.