Curing Kinetics Modeling of Epoxy Modified by Fully Vulcanized Elastomer Nanoparticles Using Rheometry Method.

In this study, the curing kinetics of epoxy nanocomposites containing ultra-fine full-vulcanized acrylonitrile butadiene rubber nanoparticles (UFNBRP) at different concentrations of 0, 0.5, 1 and 1.5 wt.% was investigated. In addition, the effect of curing temperatures was studied based on the rheological method under isothermal conditions. The epoxy resin/UFNBRP nanocomposites were characterized via Fourier transform infrared spectroscopy (FTIR). FTIR analysis exhibited the successful preparation of epoxy resin/UFNBRP, due to the existence of the UFNBRP characteristic peaks in the final product spectrum. The morphological structure of the epoxy resin/UFNBRP nanocomposites was investigated by both field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) studies. The FESEM and TEM studies showed UFNBRP had a spherical structure and was well dispersed in epoxy resin. The chemorheological analysis showed that due to the interactions between UFNBRP and epoxy resin, by increasing UFNBRP concentration at a constant temperature (65, 70 and 75 °C), the curing rate decreases at the gel point. Furthermore, both the curing kinetics modeling and chemorheological analysis demonstrated that the incorporation of 0.5% UFNBRP in epoxy resin matrix reduces the activation energy. The curing kinetic of epoxy resin/UFNBRP nanocomposite was best fitted with the Sestak-Berggren autocatalytic model.

Novel chitosan/γ-alumina/carbon quantum dot hydrogel nanocarrier for targeted drug delivery.

Curcumin (CUR) is among the most natural and effective antitumor drugs for cancer treatment. These drugs have low solubility and short half-lives that reduce their effectiveness in drug release systems. Herein, a hydrogel nanocarrier containing chitosan (CS), alumina (γ-Al2O3), and carbon quantum dots (CQDs) was prepared by the water-in-oil-in-water (W/O/W) double nanoemulsion method. DLS revealed a nanocarrier size of 227 nm, with a zeta potential of -37.8 mV, which corroborates its stability. FE-SEM showed its quasi-spherical shape, FT-IR and XRD confirmed the presence of all the components in the nanocomposite and gave information about the intermolecular interactions between them and the crystalline nature of the nanocarrier, respectively. The drug loading (48 %) and entrapment efficiency (86 %) were higher than those reported previously for other CUR nanocarriers. The drug release profile revealed a controlled and stable release, and a pH-sensitive behavior, with faster CUR release in an acid environment. The breast cancer cell line was examined by cytotoxicity and cell apoptosis analyses. The results showed that the slow release over time and the programmed cell death were due to interactions between CUR and the nanocarrier. Considering the results obtained herein, CS/γAl2O3/CQDs/CUR can be considered as a promising new nanosystem for tumor treatment.

Anticancer activity of thymoquinone against breast cancer cells: Mechanisms of action and delivery approaches.

The rising incidence of breast cancer has been a significant source of concern in the medical community. Regarding the adverse effects and consequences of current treatments, cancers' health, and socio-economical aspects have become more complicated, leaving research aimed at improved or new treatments on top priority. Medicinal herbs contain multitarget compounds that can control cancer development and advancement. Owing to Nigella Sativa's elements, it can treat many disorders. Thymoquinone (TQ) is a natural chemical derived from the black seeds of Nigella sativa Linn proved to have anti-cancer and anti-inflammatory properties. TQ interferes in a broad spectrum of tumorigenic procedures and inhibits carcinogenesis, malignant development, invasion, migration, and angiogenesis owing to its multitargeting ability. It effectively facilitates miR-34a up-regulation, regulates the p53-dependent pathway, and suppresses Rac1 expression. TQ promotes apoptosis and controls the expression of pro- and anti-apoptotic genes. It has also been shown to diminish the phosphorylation of NF-B and IKK and decrease the metastasis and ERK1/2 and PI3K activity. We discuss TQ's cytotoxic effects for breast cancer treatment with a deep look at the relevant stimulatory or inhibitory signaling pathways. This review discusses the various forms of polymeric and non-polymeric nanocarriers (NC) and the encapsulation of TQ for increasing oral bioavailability and enhanced in vitro and in vivo efficacy of TQ-combined treatment with different chemotherapeutic agents against various breast cancer cell lines. This study can be useful to a broad scientific community, comprising pharmaceutical and biological scientists, as well as clinical investigators.