Colorimetric Cu2+ Detection of (1E,2E)-1,2-Bis((1H-pyrrol-2-yl)methylene)hydrazine Using a Custom-Built Colorimeter.

The compound (1E,2E)-1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine (1) was investigated for its chemosensor application. The colorimetric response of 1 with various ions was investigated, and the selective optical change upon mixing with Cu2+ was found. The Cu2+ binding stoichiometry of 1 derived from Job's plot and the in silico study give us the tentative structural detail of the binding mode of 1 and Cu2+ being 1:1. The binding constant between 1 and Cu2+ from the Benesi-Hildebrand plot was 1.49 × 104 M-1. The limit of detection of 1 in Cu2+ detection was 0.64 µM (0.040 ppm), which is much lower than the WHO and US EPA maximum allowable Cu2+ level in drinking water (2 and 1.3 ppm, respectively). The custom-built colorimeter demonstrates a good linear relationship between Cu2+ concentration and electrical resistance (Ω) upon 1-Cu2+ ion binding.

Genistein-modified poly(ethylene oxide)/poly(D,L-lactic acid) electrospun mats with improved antioxidant and anti-inflammatory properties.

Genistein is a phytochemical with a broad range of desirable biological activity for wound healing. However, its poor bioavailability requires developing a new method for fabricating an appropriate carrier vehicle to deliver genistein in a sustained manner. Based on the guidance afforded by the ternary phase diagram of poly(D,L-lactic acid) (PDLLA), poly(ethylene oxide) (PEO), and genistein blends, certain selective compositions were electrospun. We obtained a uniformly smooth surface morphology in unmodified and genistein-modified PEO/PDLLA fibers, documented by scanning electron microscopy. Moreover, wide-angle X-ray diffraction and 1H NMR studies revealed that the genistein molecules, successfully incorporated in the blends, remained chemically stable after electrospinning. Besides surface wettability and dimensional stability of the electrospun mats, the released genistein amount has been evaluated as a function of PEO concentration. Our biocompatibility investigations suggest that genistein-modified PEO/PDLLA electrospun mats exhibit strong antioxidant and anti-inflammatory activities which indicate they have potential applications for wound dressings.

Solubilization of genistein in poly(oxyethylene) through eutectic crystal melting.

Solid-liquid phase diagrams of binary crystalline blends of genistein with poly(ethylene oxide) (PEO) and poly(ethylene glycol) (PEG) were established experimentally and theoretically based on the combined Flory-Huggins free energy of liquid-liquid phase separation and the phase field free energy pertaining to crystal solidification. The liquidus lines obtained self-consistently were found to agree well with trends of depressed crystal melting transitions in genistein/PEO and genistein/PEG blends, exhibiting eutectic phase behavior. Of particular importance is the lowering of the eutectic temperature of the genistein/PEO blend by about 60 °C upon switching to the genistein/PEG system. The occurrence of interspecies hydrogen bonding between genistein molecules and both PEO and PEG chains, albeit weak, was noticed by Fourier transform infrared spectroscopy. The improved solubility of genistein in PEG can be attributed not only to lowering of the molecular weight of PEG utilized, but also to its terminal hydroxyl groups. This eutectic melting approach by PEG solvent is sufficiently effective in solubilizing genistein crystals that development of genistein-containing drugs might be feasible for injection and/or oral administration.