Synthesis of hydroxyapatite/polyethylene glycol 6000 composites by novel dissolution/precipitation method: optimization of the adsorption process using a factorial design: DFT and molecular dynamic.

In this work, we presented a synthesis of a composite based on HAp and PEG 6000 using a new method of synthesis dissolution precipitation to be applied for application of wastewater purification from toxic metal ions. Multiple characterization methods were used to analyze the morphology and the structure of the well-prepared compounds including FT-IR, Raman, XRD, XPS, TGA and SEM were used to conduct a composite analysis. The adsorption effectiveness of this analysis towards Pb2+ and various other hazardous metal ions found in sewage was assessed. Batch experiments were conducted to optimize the various operational parameters including adsorbent dose, temperature, pH, contact time, and initial concentration. The Langmuir isotherm was used to fit the data, and it predicted monolayer adsorption with a maximum capacity of 67 mg g-1 for HAP PEG600 and 60 mg g-1 for HAp. A pseudo-second-order equation fits the adsorption process well (0.961-0.971). The thermodynamic data support the spontaneous metal bonding to the composite receptor sites. Theoretical calculations showed that the interaction strength is very strong and gets stronger when the PEG6000 is deprotonated. The results presented here are supported by evidence acquired from experiments. Theoretical computation using Monte Carlo (MC) and Molecular Dynamic (MD) simulation models showed excellent affinity of prepared foams for the model ion Pb2+ with highly negative adsorption energy values indicating vigorous interactions of Pb2+ with the adsorbate surfaces.

Comparative chemical examination of inclusion complexes formed with ß-cyclodextrin derivatives and basic amino acids.

In this study, we have investigated the host-guest inclusion complexes between ß-cyclodextrin (ßCD), 2-hydroxypropyl-ß-cyclodextrin (2-HPßCD), and mono-6-tosyl-ß-cyclodextrin (TS-ßCD) excipients and two amino acids, such as L-arginine (L-Arg) and L-lysine (L-Lys). The formation of inclusion complexes was detected, and a comparative study was conducted at different pH, density, and viscosity. A physical mixture, comprising equal amount of amino acids was used to prepare the complex in a solid-state form. The experimental parameters, such as apparent molar volume, limiting apparent molar volume, partial molar volume were analyzed by measuring density at infinite dilution. The other quantities, such as dynamic viscosity, kinematic viscosity, relative viscosity, intrinsic viscosity, spatial viscosity, activation energy were determined for amino acid/ßCD complexes at various mass fractions of ßCDs and different temperatures. Finally, we found moderate (R2 > 0.5) and strong (R2 > 0.7) linear relationships (p-value < 0.0001) between the dynamic viscosity and the temperature: the temperature evaluation promotes the decrease in dynamic viscosity for amnio acid-ßCD (its derivatives) complexes. The results of this study emphasize important properties of analyzed complexes that can be utilized in the development of controlled drug delivery vectors.

Probing inclusion complexes of 2-hydroxypropyl-ß-cyclodextrin with mono-amino mono-carboxylic acids: physicochemical specification, characterization and molecular modeling.

Density (ρ), viscosity (η) and surface tension (γ) of three amino acids (valine, alanine, and glycine) have been measured at a different mass fraction (0.002 - 0.009) of aqueous hydroxypropyl-ß-cyclodextrin (HPßCD) mixtures and different temperatures (278.15 - 295.15 K). The formation of inclusion complexes has been analyzed via evaluating the amounts of apparent and limiting apparent molar volumes, limiting apparent molar expansibilities, activation energy, kinematic, relative, intrinsic, spatial, and dynamic viscosities. The surface tension studies indicated that the inclusion complexes have been formed with 1:1 stoichiometry and mediated by hydrophobic effects and electrostatic forces. Additionally, the ρ and η parameters were evaluated by molecular modeling experiments to provide more details on the mechanisms of the complexation.

Degradation of pristine and oxidized single wall carbon nanotubes by CYP3A4.

Carbon nanotubes (CNTs) are a class of carbon based nanomaterials which have attracted substantial attention in recent years as they exhibit outstanding physical, mechanical and optical properties. In the last decade many studies have emerged of the underlying mechanisms behind CNT toxicity including malignant transformation, the formation of granulomas, inflammatory responses, oxidative stress, DNA damage and mutation. In the present investigation, we studied the biodegradation of single-walled carbon nanotubes (SWCNTs) by Cytochrome P450 enzymes (CYP3A4) through using Raman spectroscopy. CYP3A4 is known isozyme accountable for metabolizing various endogenous and exogenous xenobiotics. CYP3A4 is expressed dominantly in the liver and other organs including the lungs. Our results suggest that CYP3A4 has a higher affinity for p-SWNTs compared to c-SWNTs. HEK293 cellular viability was not compromised when incubated with SWNT. However, CYP3A4 transfected HEK293 cell line showed no digestion of c-SWNTs after incubation for 96 h. Cellular uptake of c-SWNTs was observed by electron microscopy and localization of c-SWNTs was confirmed in endosomal vesicles and in the cytoplasm. This is the first study CYP3A4 degrading both p-SWNTs and c-SWNTs in an in vitro setup. Interestingly, our results show that CYP3A4 is more proficient in degrading p-SWNTs than c-SWNTs. We also employed computational modeling and docking assessments to develop a further understanding of the molecular interaction mechanism.

Detailed chemical characterization and molecular modeling of serotonin inclusion complex with unmodified ß-cyclodextrin.

In this study, we analyzed the capability of unmodified ß-cyclodextrin (ß-CD) to form the stable complex with serotonin hydrochloride (SER), as an important neurotransmitter in the brain. The stable ß-CD: SER formulation was prepared and characterized using spectroscopic, thermal, molecular docking, and molecular dynamics techniques, revealing the phenomenon of H-bond formations and the domination of hydrophobic forces between the host molecule and its guest via the amine group of SER and the narrow side of ß-CD. The complexation mechanism was mainly enthalpy-driven, representing the improvement in SER photo-stability. Overall, the results highlighted the possibility to use this formulation with improved stability in clinical practice for treatment and prevention of various depressive conditions, such as anxiety disorders.

Selective suppression of excessive GluN2C expression rescues early epilepsy in a tuberous sclerosis murine model.

Tuberous sclerosis complex (TSC), caused by dominant mutations in either TSC1 or TSC2 tumour suppressor genes is characterized by the presence of brain malformations, the cortical tubers that are thought to contribute to the generation of pharmacoresistant epilepsy. Here we report that tuberless heterozygote Tsc1(+/-) mice show functional upregulation of cortical GluN2C-containing N-methyl-D-aspartate receptors (NMDARs) in an mTOR-dependent manner and exhibit recurrent, unprovoked seizures during early postnatal life (