Water Dispersible Nanocomposite Research Articles

Cyanine-Assisted Exfoliation of Covalent Organic Frameworks in Nanocomposites for Highly Efficient Chemo-Photothermal Tumor Therapy.

Covalent organic frameworks (COFs) have received considerable interest because of their advanced applications. However, their low dispersibility and aqueous stability are intractable issues limiting their biomedical application. To address the issue, water-dispersible nanocomposites (COF@IR783) produced through the assembly of cyanines and COFs are proposed and prepared. Therefore, a strategy of "killing three birds with one stone" is developed. First, the nanocomposites exhibit superior dispersibility and aqueous stability compared to COFs. The nanocomposites have a nanosized morphology and negative charges, which are in favor of improving the blood circulation and enhanced permeability and retention-mediated tumor-targeting delivery therapy for in vivo application. Second, the nanocomposites have enhanced photothermal therapy (PTT) ability in the near-infrared region compared to cyanines. The nanocomposites also have a photoacoustic imaging ability, which can guide the antitumor therapy in vivo. Lastly, the nanocomposites can be further used as drug-delivery carriers for loading the anticancer cis-aconityl-doxorubicin (CAD) prodrug. In comparison with individual PTT or chemotherapy, the combination of PTT and chemotherapy achieved with COF@IR783@CAD synergistically induced the death of cancer cells in vitro, and an intravenous injection of COF@IR783@CAD in mice resulted in significant tumor ablation. This work indicates that the dispersibility and aqueous stability of COFs can be appropriately overcome through a rational design and can further expand the biomedical applications of COFs.

Facile fabrication of water-dispersible nanocomposites based on hexa-peri-hexabenzocoronene and Fe3O4 for dual mode imaging (fluorescent/MR) and drug delivery

The facile fabrication of multifunctional nanocomposites (Fe3O4/HBC@F127) consisting of superparamagnetic Fe3O4 nanoparticles and fluorescent organic hexa-peri-hexabenzocoronene (HBC) molecules incorporated in block copolymer diacylphospholipid–polyethyleneglycol F127 have been demonstrated for dual mode imaging (fluorescent/MR) and drug delivery. The obtained nanocomposites were water-dispersible, stable and biocompatible, as confirmed by dynamic light scattering (DLS) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Relativity measurements showed a T2 relaxivity (r2) of 214.61 mM−1 s−1, which may be used as T2-weighted MR imaging agents. In vitro imaging studies indicated that the nanocomposites had good MR and fluorescence imaging effects with low cytotoxicity. Besides, the developed nanocomposites could also be applied as drug delivery vehicles. Doxorubicin (DOX) loaded Fe3O4/HBC@F127 nanocomposites significantly inhibited the growth of human hepatoma cells (HepG2). These findings suggested that the facile synthesized multifunctional nanocomposites may be used as a platform for dual mode imaging (both MR and fluorescence) and drug delivery.

Ice-Assisted Synthesis and Characterization of Water-Dispersible Nanocomposites Based on Polyaniline and Polymer Acid Surfactants

Ice-Assisted Synthesis and Characterization of Water-Dispersible Nanocomposites Based on Polyaniline and Polymer Acid Surfactants

Engineered water-soluble two-dimensional magnetic nanocomposites: towards highly magnetic relaxometric properties.

Water dispersible two-dimensional magnetic nanocomposites are formed by phase-transferring hydrophobic manganese-doped ferrite nanoparticles (MFPs) into aqueous solvent using a one-step simple approach involving only graphene oxide (GO) as the phase transfer agent. The resultant hydrophilic magnetic nanocomposites (MFNs) are surprisingly stable in the aqueous phase despite its large hydrodynamic size (dhyd). Because of its unique construct that promotes water accessibility towards the MFP core, large MFNs loaded with an 18 nm MFP core (MFN-18; dhyd = 577.9 nm) exhibits transverse relaxivity (r2) up to ∼6.8 times (r2 = 800.8 mM [Mn + Fe](-1) s(-1)) higher than the typical individually coated MFP-18 with amphiphilic brush copolymers (r2 = 117.3 mM [Mn + Fe](-1) s(-1)). Meanwhile, the overall nanocomposites dhyd can be further reduced by employing a smaller pre-sonicated GO sheet phase transfer agent. As a result of using small GO sheets with enhanced hydrophilicity, the r2 of small MFN-18* nanocomposites (dhyd = 224.9 nm) increases by approximately 37% (r2 = 1097.4 mM [Mn + Fe](-1) s(-1)) as compared to larger MFN-18. From a simple comparative study among various magnetic nanocomposites involving a MFP-18 core, the high MFN-18 r2 relaxivity value can be attributed to enhanced water diffusion and exchange due to the GO sheet, allowing better interaction between magnetic the MFP core and water protons. The proposed method can be readily extended to convert other types of hydrophobic nanoparticles into water-dispersible nanocomposites.

Water dispersible cross-linked magnetic chitosan beads for increasing the antimicrobial efficiency of aminoglycoside antibiotics

The aim of this study was to obtain a nano-active system to improve antibiotic activity of certain drugs by controlling their release. Magnetic composite nanomaterials based on magnetite core and cross-linked chitosan shell were synthesized via the co-precipitation method and characterized by Fourier transform infrared spectroscopy (FT-IR), infrared microscopy (IRM), scanning electron microscopy (SEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The prepared magnetic composite nanomaterials exhibit a significant potentiating effect on the activity of two cationic (kanamycin and neomycin) drugs, reducing the amount of antibiotics necessary for the antimicrobial effect. The increase in the antimicrobial activity was explained by the fact that the obtained nanosystems provide higher surface area to volume ratio, resulting into higher surface charge density thus increasing affinity to microbial cell and also by controlling their release. In addition to the nano-effect, the positive zeta potential of the synthesized magnetite/cross-linked chitosan core/shell magnetic nanoparticles allows for a more favorable interaction with the usually negatively charged cell wall of bacteria. The novelty of the present contribution is just the revealing of this synergistic effect exhibited by the synthesized water dispersible magnetic nanocomposites on the activity of different antibiotics against Gram-positive and Gram-negative bacterial strains. The results obtained in this study recommend these magnetic water dispersible nanocomposite materials for applications in the prevention and treatment of infectious diseases.

Water dispersible avermectin-layered double hydroxide nanocomposites modified with sodium dodecyl sulfate

Sodium dodecyl sulfate was utilized to modify the avermectin-layered double hydroxide nanohybrids for the preparation of water dispersible nanocomposites, resulting in the successful conversion of hydrophobic surfactant monolayer structure on the solid surface to hydrophilic bilayer. Concentrations of SDS and NaCl had important effects on the bilayer formation, and the highest suspensibility of the obtained nanocomposites reached 97.6%. All the samples were characterized using Fourier transform-infrared spectroscopy, X-ray diffraction, transmission electron microscopy, element analysis, zeta potential and contact angle measurements. It was found that the prepared materials could well control the release of avermectin, and the prepared nanocomposite would be a promising candidate for water dispersible controlled release formulation.

Hierarchical gold/copolymer nanostructures as hydrophobic nanotanks for drug encapsulation

Various nanoparticles are used to fabricate innovative systems for drug encapsulation and cancer therapy. In this paper, the hierarchical core-shell nanostructures composed of gold nanoparticles and poly(dimethylsiloxane)-poly(ethylene glycol) (PDMS-PEG) block copolymers are fabricated via a hydrosilylation reaction. The obtained gold/copolymer nanocomposites display a desired amphiphilic property and can be well-dispersed in water when the PEG blocks are long enough. The hydrophobic drug hypocrellin B (HB) can be encapsulated into these water-dispersible nanocomposites based on the hydrophobic-hydrophobic interaction between HB molecules and PDMS segments. The gold/copolymer nanocomposites loaded with HB show a rational anticancer ability in the photodynamic therapy although the gold/copolymer nanocomposites without drug also have a little cytotoxicity. Such hierarchically structured core-shell nanocomposites can be considered as water-dispersible nanotanks for hydrophobic drugs in the development of multifunctional biodelivery systems.

A Water Dispersible Nanocomposite of Polyacrylonitrile with Silica via Aqueous Polymerization of Acrylonitrile by K2CrO4–NaAsO2 Redox System

The aqueous polymerization of acrylonitrile initiated by the redox pair, potassium chromate-sodium arsenite produced polyacrylonitrile which was recovered as a coagulum in the medium. A simple procedure was developed for obtaining a stable suspension of polyacrylonitrile-SiO2 nanocomposite by conducting the polymerization in presence of SiO2 as a particulate dispersant. SEM analyses revealed distinct morphological features of the polyacrylonitrile-SiO2 nanocomposite. TEM analyses indicated the particle sizes of the polyacrylonitrile-SiO2 composite to be in the 28–100 nm range. TG analyses revealed the enhanced thermal stability of the polyacrylonitrile-SiO2 nanocomposite relative to that of the base polymer polyacrylonitrile. The d.c. conductivities of the polyacrylonitrile-SiO2 and polyacrylonitrile-SiO2 (FeCl3 doped) composites were in the order of 10-6 S cm-1 and 10-5 S cm-1 respectively.

Preparation and evaluation of composites from montmorillonite and some heterocyclic polymers: 3. a water dispersible nanocomposite from pyrrole-montmorillonite polymerization system

Montmorillonite (MMT)-based nanocomposites of polypyrrole (PPY) were prepared through the polymerization of pyrrole with MMT and FeCl 3-impregnated MMT in bulk and in aqueous medium. The composites were characterized by IR, X-ray diffraction (XRD), and scanning electron microscopy (SEM) studies. XRD analyses revealed no change in d 001 spacing in MMT (9.8 Å), suggesting no intercalation of PPY into MMT lamellae. TEM analysis indicated the particle size to be 25 ± 7 nm. The bulk conductivity of the composites was in the range of (1.3 to 26) × 10 −5 S/cm, depending on the FeCl 3-impregnation level and on the PPY loading in the composites. Suitable procedures were developed for obtaining a stable aqueous dispersion and a reversible dispersion of these composites.