Synthesis and Characterization of Quercetin-Iron Complex Nanoparticles for Overcoming Drug Resistance.

Quercetin, one of the major natural flavonoids, has demonstrated great pharmacological potential as an antioxidant and in overcoming drug resistance. However, its low aqueous solubility and poor stability limit its potential applications. Previous studies suggest that the formation of quercetin-metal complexes could increase quercetin stability and biological activity. In this paper, we systematically investigated the formation of quercetin-iron complex nanoparticles by varying the ligand-to-metal ratios with the goal of increasing the aqueous solubility and stability of quercetin. It was found that quercetin-iron complex nanoparticles could be reproducibly synthesized with several ligand-to-iron ratios at room temperature. The UV-Vis spectra of the nanoparticles indicated that nanoparticle formation greatly increased the stability and solubility of quercetin. Compared to free quercetin, the quercetin-iron complex nanoparticles exhibited enhanced antioxidant activities and elongated effects. Our preliminary cellular evaluation suggests that these nanoparticles had minimal cytotoxicity and could effectively block the efflux pump of cells, indicating their potential for cancer treatment.

Synthesis and characterization of iron oxide superparticles with various polymers.

Iron oxide superparticles referring to a cluster of smaller nanoparticles have recently attracted much attention because of their enhanced magnetic moments but maintaining superparamagnetic behavior. In this study, iron oxide superparticles have been synthesized using a solvothermal method in the presence of six different polymers (e.g., sodium polyacrylate, pectin sodium alginate, chitosan oligosaccharides, polyethylene glycol, and polyvinylpyrrolidine). The functional group variation in these polymers affected their interactions with precursor iron ions, and subsequently influenced crystalline grain sizes within superparticles and their magnetic properties. These superparticles were extensively characterized by transmission electron microscopy, dynamic light scattering, x-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometry.

Enhanced legume root growth with pre-soaking in α-Fe2O3 nanoparticle fertilizer.

The rising demand for food and energy crops has triggered interest in the use of nanoparticles for agronomy. Specifically, iron oxide-based engineered nanoparticles are promising candidates for next-generation iron-deficiency fertilizers. We used iron oxide and hybrid Pt-decorated iron oxide nanoparticles, at low and high concentrations, and at varied pHs, to model seed pre-soaking solutions for investigation of their effect on embryonic root growth in legumes. This is an environmentally friendly approach, as it uses less fertilizer, therefore less nanoparticles in contact with the soil. Analysis from varied material characterization techniques combined with a statistical analysis method found that iron oxide nanoparticles could enhance root growth by 88-366% at low concentrations (5.54 × 10-3 mg L-1 Fe). Hybrid Pt-decorated iron oxide nanoparticles and a higher concentration of iron oxide nanoparticles (27.7 mg L-1 Fe) showed reduced root growth. The combined materials characterization and statistical analysis used here can be applied to address many environmental factors to finely tune the development of vital nanofertilizers for high efficiency food production.

A general approach to the synthesis and detailed characterization of magnetic ferrite nanocubes.

A general approach to the synthesis and detailed characterization of magnetic ferrite nanocubes were reported, where the nanocubes were synthesized by the thermal decomposition of metal-oleate complexes following a step-heating method. The doping ions were introduced during the precursor preparation by forming M(2+)/Fe(3+) oleate mixed complex (M(2+) = Fe(2+), Mn(2+), Zn(2+), Cu(2+), Ca(2+), and Mg(2+)). The mechanistic studies showed that the presence of sodium oleate in combination with step-heating was critical for the formation of the cubic shapes for the doped magnetic ferrites. The nanocubes were extensively characterized, including morphology and crytsal structure by advanced transmission electron microscopy, doping level and distribution by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy, cation distribution within the spinel structures by Fourier transform infrared and Raman spectroscopy, and magnetic properties by alternating gradient magnetometer at room temperature.

Controlled synthesis of iron oxide nanoplates and nanoflowers.

An effective approach to synthesizing crystalline iron oxide nanoplates (~3 nm thick) and nanoflowers composed of ~5 nm small grains was reported. The formation of different-shaped nanoparticles in a similar system was achieved by controlling the nucleus concentration and growth rate.

Synthesis and growth mechanism of iron oxide nanowhiskers.

Iron oxide nanowhiskers with dimensions of approximately 2 × 20 nm were successfully synthesized by selectively heating an iron oleate complex. Such nanostructures resulted from the difference in the ligand coordination microenvironments of the Fe(III) oleate complex, according to our electronic structure calculations and thermogravimetric analysis. A ligand-directed growth mechanism was subsequently proposed to rationalize the growth process. The formation of the nanowhiskers provides a unique example of shape-controlled nanostructures, offering additional insights into nanoparticle synthesis.