Effective parameters in determining cross-linked dextran microsphere characteristics: screening by Plackett-Burman design-of-experiments.

This study aims to screen the effective parameters in preparing cross-linked dextran microspheres (CDMs) to make them controllable for obtaining microspheres with tunable properties. Microspheres were prepared by chemical crosslinking of dextran dissolved in internal phase of an inverse emulsion system (W/O) using epichlorohydrin (ECH). A Plackett-Burman design-of-experiments was employed as the screening methodology to investigate the effects of the kinetics and process parameters, i.e. the mixing speed and emulsification time on the resulting microsphere characteristics. Crosslinking reaction temperature and concentrations of the emulsion constituents including dextran, ECH and sodium hydroxide were the studied kinetic parameters. Equilibrium swelling ratio, mean particle size and size distribution of the resulting CDMs were measured and statistically analysed. It was found that dextran concentration is the most influential parameter on the particle size and swelling ratio of the obtained CDMs. Increasing dextran concentration in the aqueous phase leads to a significant increase in the mean particle size and decrement in water uptake capacity of the resulting microspheres, respectively.

Facile synthesis of hollow spherical g-C3N4@LDH/NCQDs ternary nanostructure for multifunctional antibacterial and photodegradation activities.

Heterojunction nanostructure construction and morphology engineering are considered to be effective approaches to improve photocatalytic performance. Herein, ternary hierarchical hollow structures consisting of cobalt-aluminum-layered double hydroxide (CoAl-LDH) nanoplates grown on hollow carbon nitride spheres (HCNS) and decorated with N-doped carbon quantum dots (NCQDs) were prepared using a templating method and a subsequent solvothermal process. The obtained HCNS@LDH/NCQD composites presented an improved performance in photocatalytic degradation of tetracycline and inactivation of E. coli compared with pure HCNS and LDH under visible light illumination. The enhanced photocatalytic activity of the designed photocatalyst could be attributed to the following reasons: (1) A special hollow structure provides more active sites and has multiple capabilities of light reflection by helping with a high specific surface area that improves the harvesting efficiency of solar light and (2) the strong synergistic effect among the constituents, which promotes separation and transfer of charge carriers and broadens the photo-response range.

Solid-state photochromism of spironaphthoxazine loaded microcapsules with photo-patterning and thermo-regulating features.

HYPOTHESIS: One of the biggest challenges in the field of photoresponsive spirooxazines is their fast reverse isomerization. Polar phase change materials beside spirooxazines not only stabilize their colored-form, but also induce thermo-regulating properties to the whole system. Moreover, encapsulation is a key route to protect them and provide safe application of photochromic materials in solid-state matrices. EXPERIMENTS: A solution of spironaphthoxazine in oleic acid was encapsulated through solvent evaporation technique and the obtained microcapsules were incorporated in a transparent polymeric coating and also non-woven cotton fabrics. A systematic study on the reverse isomerization rate of spironaphthoxazine, photo-patterning and thermo-regulating features of the microcapsules was performed. FINDINGS: Comprehensive analyses demonstrated successful encapsulation of oleic acid and spironaphthoxazine. Microcapsules showed reversible color changes upon UV-Vis irradiation below melting point of oleic acid and a 85% decrease in discoloration rate compared to those without oleic acid. They also exhibited excellent photoswitchability, making them suitable for anti-counterfeiting applications. Their thermo-regulating feature in cotton fabrics was studied by using of infrared camera and they represented energy saving potentiality. Optically monitoring of temperature around melting point of oleic acid is another feature of these microcapsules.

High performance cyanide sensing with tunable limit of detection by stimuli-responsive gold nanoparticles modified with poly (N,N-dimethylaminoethyl methacrylate).

Detection of cyanide ion (CN-) and design of new sensors with high sensitivity and selectivity are interesting topics in recent developments. Cyanide ions lead to immediate dissolution of gold nanoparticles (AuNPs) and distinct color changes from red to transparent colorless solution. The presence of any material e.g. stabilizer may affect dissolution mechanism and hence sensing properties. Here, we represent a novel sensor (Au-PDA) based on the AuNPs coated with poly (N,N-dimethylaminoethyl methacrylate) (PDMAEMA) for the detection of CN- with tunable sensitivity. PDMAEMA bearing tertiary amine groups not only induced stimuli-responsivity to the prepared Au-PDA as the sensor, but also influenced the sensing performance like linear response range and limit of detection (LOD). The detection process with the increase in CN- concentration in wide range of pHs as well as high ionic strength of the medium was monitored by reduction of the localized surface plasmon resonance band of AuNPs at 530 nm. In the optimized condition, this sensing approach exhibited excellent selectivity in contrary to other anions and cations. The highest sensitivity was obtained in basic media (i.e. pH 9) with a LOD of 4.7 × 10-6 µM and two linear ranges from 10-5-10-3 µM and 0.04-320 µM. The tunable sensitivity could be considered as the strength point of such sensor with lowest LOD for detection of CN- and such a controlled stimuli-responsivity will open up a promising route toward adjustable detection of other chemicals.

Controlled Release and Photothermal Behavior of Multipurpose Nanocomposite Particles Containing Encapsulated Gold-Decorated Magnetite and 5-FU in Poly(lactide-co-glycolide).

Nowadays, many research studies have been conducted to prepare multidisciplinary probes in drug delivery systems and cancer therapy with high performance and minimum side effects. Here, poly(lactide-co-glycolide) (PLGA) nanocomposite particles containing 5-fluorouracil (5-FU) and gold-decorated magnetite nanoparticles with a raspberry-like morphology were designed and prepared as a novel and anticancer probe. For this reason, Fe3O4 nanoparticles were synthesized by a coprecipitation method and modified with (3-mercaptopropyl) trimethoxysilane for the deposition of gold nanoparticles. Then, they were embedded in the PLGA matrix alone and accompanied by 5-FU with 92 and 88% loading efficiencies, respectively, through a multiple emulsion solvent evaporation method. Chemical structure and composition of the prepared samples in each step were completely characterized by several techniques. The morphology of the nanocomposite particles was assessed by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and selected area electron diffraction patterns, and their particle size and colloidal stability after 1 week were evaluated by dynamic light scattering. Because of the coexistence of gold and Fe3O4 nanoparticles, the final probe provided enhanced dual magneto and photothermal responses by increasing the temperature up to 42.7 °C under 5 min external alternating magnetic field and to 42.1 °C within just 1 min near-infrared irradiation at 808 nm. Trypan blue dye exclusion assays showed that they are biocompatible with reasonable toxicity (IC50 of 0.62 mg/mL) with respect to DU145 prostate cancer cells. Drug release profile of the 5-FU-loaded nanocomposite particles demonstrated their controlled release at 37 °C in phosphate-buffered saline solution. These indicate multidisciplinary characteristics of such particles in cancer therapy by photothermal, magnetic hyperthermia, and chemotherapy according to the presence of various active components.

The effects of Salvia officinalis L. on granulosa cells and in vitro maturation of oocytes in mice.

BACKGROUND: Salvia officinalisL. has been used since ancient times but there are little data about effects of this herb on normal reproductive cells. OBJECTIVE: To investigate the toxicity effects of Salvia officinalis L. on granulosa cells (GCs) and maturation of oocytes. MATERIALS AND METHODS: GCs and oocytes were extracted from superovulated ovaries of immature mice. The cells were treated with concentrations of 10, 50, 100, 500, and 1000 µg/ml of Salvia officinalis hydroalcoholic extracts and compared with the control culture. Bioviability, chromatin condensation, estradiol and progesterone concentrations, lipid synthesis, apoptosis, and alkaline phosphatase activity of GCs were measured. In vitro maturation of oocytes by determination of different maturation stages of oocytes including germinal vesicle, germinal vesicle breaks down, and metaphase II were examined. RESULTS: The results revealed that 500 and 1000 µg/ml concentrations of Salvia officinalisL. were toxic. The most of the GCs were in the early stages of apoptosis in 100 µg/ml treated culture and cell death happened with 500 µg/ml treatment. Progesterone concentration was reduced in 100 µg/ml and higher doses but estradiol concentration and alkaline phosphatase showed opposite effects. The lipid droplets content of GCs reduced significantly in all groups especially in 500 and 1000 µg/ml. Finally, oocyte's nucleus and cytoplasm showed a high level of condensation, and meiosis rate reduced in all treated cultures. CONCLUSION: Our findings suggested that higher dose of Salvia officinalis hydroalcoholic extracts inhibits, oocyte maturation, GCs bioviability, proliferation, and secretion.