Magnetically-active Pickering emulsions stabilized by hybrid inorganic/organic networks.

Magnetically-active hybrid networks (MHNs) are complex inorganic/organic composite materials that have been synthesized from the coupling of amine-functionalized iron oxide nanoparticles (amine-IONs) and pre-assembled shell crosslinked knedel-like (SCK) polymeric nanoconstructs. The intricate structure of these materials is composed of several inter-connected bundles of SCKs covalently bound to amine-IONs, which afford them magnetic responsivity. The MHNs were originally designed to sequester complex hydrocarbons from water; however, they have displayed a remarkable ability to form stable Pickering emulsions between organic solvents and water, upon mechanical stimulus. Two methods of emulsification, vortex and probe sonication, have been utilized to yield magnetically-active toluene-in-water and dodecane-in-water emulsions, which are stable for up to two months in the presence of the MHNs. A detailed study of the effect of the water-to-oil (W : O) volume ratio and the MHN concentration on the droplet size of the emulsions revealed that the smallest droplet size, and narrowest dispersity were obtained at a W : O = 3 : 1, for all conditions tested. Additionally, concentrations of MHNs as low as 1 mg mL-1 and 1.5 mg mL-1, for emulsions prepared via vortex and probe sonication, respectively, were sufficient to yield the smallest droplets and narrowest distributions. Furthermore, the oil droplets stabilized by the MHNs exhibited magnetic character, and could be manipulated with an external magnetic field.

Improving paclitaxel delivery: in vitro and in vivo characterization of PEGylated polyphosphoester-based nanocarriers.

Nanomaterials have great potential to offer effective treatment against devastating diseases by providing sustained release of high concentrations of therapeutic agents locally, especially when the route of administration allows for direct access to the diseased tissues. Biodegradable polyphosphoester-based polymeric micelles and shell cross-linked knedel-like nanoparticles (SCKs) have been designed from amphiphilic block-graft terpolymers, PEBP-b-PBYP-g-PEG, which effectively incorporate high concentrations of paclitaxel (PTX). Well-dispersed nanoparticles physically loaded with PTX were prepared, exhibiting desirable physiochemical characteristics. Encapsulation of 10 wt% PTX, into either micelles or SCKs, allowed for aqueous suspension of PTX at concentrations up to 4.8 mg/mL, as compared to <2.0 µg/mL for the aqueous solubility of the drug alone. Drug release studies indicated that PTX released from these nanostructures was defined through a structure-function relationship, whereby the half-life of sustained PTX release was doubled through cross-linking of the micellar structure to form SCKs. In vitro, physically loaded micellar and SCK nanotherapeutics demonstrated IC50 values against osteosarcoma cell lines, known to metastasize to the lungs (CCH-OS-O and SJSA), similar to the pharmaceutical Taxol formulation. Evaluation of these materials in vivo has provided an understanding of the effects of nanoparticle structure-function relationships on intratracheal delivery and related biodistribution and pharmacokinetics. Overall, we have demonstrated the potential of these novel nanotherapeutics toward future sustained release treatments via administration directly to the sites of lung metastases of osteosarcoma.

Polyphosphoester-based cationic nanoparticles serendipitously release integral biologically-active components to serve as novel degradable inducible nitric oxide synthase inhibitors.

A degradable polyphosphoester (PPE)-based cationic nanoparticle (cSCK), which is integrated constructed as a novel degradable drug device, demonstrates surprisingly efficient inhibition of inducible nitric oxide synthase (iNOS) transcription, and eventually inhibits nitric oxide (NO) over-production, without loading of any specific therapeutic drugs. This system may serve as a promising anti-inflammatory agent toward the treatment of acute lung injury.

Robust magnetic/polymer hybrid nanoparticles designed for crude oil entrapment and recovery in aqueous environments.

Well-defined, magnetic shell cross-linked knedel-like nanoparticles (MSCKs) with hydrodynamic diameters ca. 70 nm were constructed through the co-assembly of amphiphilic block copolymers of PAA20-b-PS280 and oleic acid-stabilized magnetic iron oxide nanoparticles using tetrahydrofuran, N,N-dimethylformamide, and water, ultimately transitioning to a fully aqueous system. These hybrid nanomaterials were designed for application as sequestering agents for hydrocarbons present in crude oil, based upon their combination of amphiphilic organic domains, for aqueous solution dispersibility and capture of hydrophobic guest molecules, with inorganic core particles for magnetic responsivity. The employment of these MSCKs in a contaminated aqueous environment resulted in the successful removal of the hydrophobic contaminants at a ratio of 10 mg of oil per 1 mg of MSCK. Once loaded, the crude oil-sorbed nanoparticles were easily isolated via the introduction of an external magnetic field. The recovery and reusability of these MSCKs were also investigated. These results suggest that deployment of hybrid nanocomposites, such as these, could aid in environmental remediation efforts, including at oil spill sites, in particular, following the bulk recovery phase.