Using Nanoparticle Tracking Analysis (NTA) to Decipher Mucoadhesion Propensity of Curcumin-Containing Chitosan Nanoparticles and Curcumin Release

Real-time nanoparticle tracking analysis (NTA) was used to evaluate the propensity of curcumin-containing chitosan nanoparticles (CUR-CS-NP) to muco adhere and release curcumin under simulated colon conditions. This novel procedure is relatively simple and fast and does not require use of animals, but more importantly, it permits the correlation of physical changes to the CUR-CS-NP with the observed behavior under simulated conditions in realtime. The CUR-CS-NP formed spontaneous aggregates in response to exposure to mucin. This observation correlated with curcumin release from CUR-CS-NP was observed in phosphate buffer (pH 7.4) where, 81% of curcumin was released within 6 hours. Atomic force microscopy imaging CUR-CS-NP exposed to mucin solution revealed a decorated surface of the CUR-CS-NP by mucin, consistent with expected electrostatic interactions between the two. The use of NTA, thus, provided us with a means of ascertaining the performance of the CUR-CS-NP under simulated colonic conditions and we propose that this prototype delivery system could be the basis for an effective colon mucoadhesive drug delivery system.      

Microwave-Assisted Synthesis and Characterization of Triton X 100 Capped Silver Nanospheres

In this article, we report the synthesis of silver nanospheres (Ag NS) by a simple microwave irradiation method using Triton X 100 (TX 100) as a capping agent. TX 100 was also observed to act as a reducing agent in the presence of microwave radiation. From the ultraviolet-visible spectrum, the formation of Ag NS was confirmed by observing surface plasmon resonance band at 414 nm. The emission band of Ag NS was observed at 482 nm from the photoluminescence (PL) spectrum. High-resolution transmission electron microscopy (HR TEM) was used to investigate the morphology of the synthesized sample. It shows that the synthesized sample has sphere-like morphology with an average diameter of 5 nm. Further, the elemental composition of the Ag NS was determined by energy dispersive x-ray analysis (EDX). Selected area electron diffraction (SAED) was used to find the crystalline nature of the Ag NS. The interaction between Ag NS and TX 100 was established by Raman spectroscopy. The electrochemical behaviour of the synthesized Ag NS was analyzed by cyclic voltammetry (CV).     

Regioselective Nitration of Phenols in O/W Microemulsion by NaNO3 and Dilute Sulfuric Acid

Highly regiospecific mononitration of phenol by NaNO₃ and dilute sulfuric acid was carried out in a TX100 oil-in-water microemulsion. Effects of various parameters such as acid type, surfactant concentration, water content, and alcohol have been investigated. The use of inexpensive and relatively nontoxic acidic reagent is an advantage of this method.      

Photophysical Investigations of Carmoisine Interacting with Conventional Cationic Surfactants Under Different pH Conditions

The present study describes the extent of interactions of an efficient food dye, Carmoisine (CAR), with conventional cationic surfactants, hexadecyltrimethylammonium bromide, and ethylhexadecyldimethylammonium bromide (EHDAB). The study was carried out by quantifying the spectral changes of CAR as a function of premicellar to postmicellar surfactant concentrations at various pH conditions. The quantification of CAR molecules entrapped by cationic micellar systems has been estimated with the help of mathematical models. Binding parameters of each surfactant were calculated using differential spectroscopic method. The enhanced solubilization of dye by switching the pH was observed. In support of the electrostatic forces, the larger and more hydrophobic head group favors the promising solubilization of CAR in the outer region of the micellar interior. These findings extend the proficiency of dye molecule as a reporter for sensing electrostatic environment in lipidic membranes and related organized assemblies.     

Curcumin-Encapsulated Hexagonal Liquid Crystalline Formed by Brij 97/NaDC Mixtures

The phase diagram of a five-components Brij 97-NaDC/IPM-PEG 400/H₂O system was determined at 25°C. The hexagonal liquid crystalline phase (H₁) was found in this system. By use of small-angle x-ray scattering (SAXS), polarization microscopy, and rheology techniques, the influence of composition, temperature, and addition of curcumin on H₁ phase was studied. It is shown that: 1) the investigated hexagonal liquid crystals exhibit a strong shear thinning behavior and viscoelasticity and the strength of the network of H₁ phase becomes weaker with increasing oil content; 2) the frequency-dependent moduli of H₁ samples decreases as the temperature increases and the steady-state limiting viscosity of the hexagonal samples shows an Arrhenius-like dependence on temperature; and 3) samples in H₁ phase containing curcumin retained their organized hexagonal structure. The SAXS results show that the curcumin molecules may be solubilized both into the apolar core of cylinders together with IPM and in the polar domain coexisting with PEG 400 between the cylinders. When curcumin is encapsulated in samples with low oil content, there is a significant decrease in the frequency-dependent moduli. The tendency of frequency behavior for samples incorporating curcumin as a function of temperature is weakened.     

Removal of Pararosaniline Hydrochloride Dye (Basic Red 9) from Aqueous Solution by Electrocoagulation: Experimental,Kinetics, and Modeling

In this work, the removal of pararosaniline hydrochloride (Basic red 9) dye from aqueous solutions by electrocoagulation was investigated. The effect of parameters such as current density, initial pH, electrolysis time, inter-electrode distance, initial dye concentration and salt concentration on dye removal efficiency were investigated. The experimental results showed that 99% dye removal was observed after 30 minutes of electrolysis for an initial dye concentration of 100 mg/L, current density of 111.1 A/m² and initial pH of 7.0. It was observed that an increase in current density, time of operation and decrease in inter-electrode distance improved the dye removal efficiency. The optimum pH range for highest dye removal was 5.0–10.25. It was also observed that increase in salt concentration in the solution reduces the specific electrical energy consumption. The kinetic study inferred that the dye removal primarily follows a first order reaction. Finally, phenomenological models were proposed to illustrate the dependence of dye removal rate constant and specific electrical energy consumption on current density, inter-electrode distance, initial dye concentration and salt concentration.     

Study of Removal of Cationic Dye from Waste Aqua Using Chromatographic Grade Silica as Adsorbent

The adsorption of cationic dye, Basic Red 13 from aqueous solution onto silica has been studied. The time growth adsorption as a function of the amount of adsorbent, pH, initial dye concentration as well as the temperature was measured of the system. Adsorption was found to follow a first-order process. Various isotherm and thermodynamic parameters for the adsorption of dye have been calculated. Isotherms were used to identify formation of either monolayer or multilayer formation whereas thermodynamic and other parameter indicated that the dye adsorption process was physisoption as well as spontaneous and exothermic in nature.     

Synthesis,Characterization, and Photocatalytic Properties of Ag/TiO2 Composite Nanofibers Prepared by Electrospinning

Ag nanoparticles (Ag NPs) embedded titanium dioxide (TiO₂) nanofibers were fabricated by colloidal sol process, electrospinning, and calcination technique. Calcination of the electrospun nanofibers were heat treated at 600°C for 180 minutes in air atmosphere. X-ray diffraction patterns exhibited that the anatase phase and silver coexisted in the resulted Ag NPs/TiO₂ nanofibers; transmission electron microscopy demonstrated Ag NPs well spread in the porous microstructure of composite fibers. The prepared nanofibers were utilized as photocatalyst for degradation of methyl orange. The degradation rate of methyl orange dye solution containing Ag/TiO₂ composite nanofibers is 99% only after irradiation for 3 hours. It is proposed that these new Ag NPs/TiO₂ composite nanofibers will have potential application in water pollution treatment.      

Interaction of Quercus Infectoria Natural Dye with Cationic and Anionic Surfactants: Adsorption/Micellization of Dye

The interaction of Indian natural dye, that is, Himalaya (Quercus infectoria) with cationic surfactant (cetyl trimethyl ammonium bromide) and anionic surfactant (sodium lauryl sulphate) has been studied. The spectrophotometric data showed an interaction between the natural dye and surfactants. Critical micelle concentration (CMC) of the surfactants, determined by measurement of specific conductance and surface tension methods, was found to be increase in case of anionic surfactant while that was found to decrease in case of cationic surfactant. Thermodynamic and surface parameters showed domination of micellization of dye in case of cetyl trimethyl ammonium bromide and domination of adsorption of dye in case of sodium lauryl sulphate.     

Polymer-Surfactant Interactions and the Effect of Tail Size Variation on Micellization Process of Cationic ATAB Surfactants in Aqueous Medium

The interactions between oppositely charged surfactant-polymer systems have been studied using surface tension and conductivity measurements and the dependence of aggregation phenomenon over the polyelectrolyte concentration and chain length of cationic ATAB surfactants, cetyltrimethyl ammonium bromide (CTAB), tetradecyltrimethyl ammonium bromide (TTAB), and dodecyltrimethyl ammonium bromide (DTAB) have been investigated. It was observed that cationic surfactants induce cooperative binding with anionic polyelectrolyte at critical aggregation concentration (cac). The cac values of ATAB surfactants in the presence of anionic polyelectrolyte, sodium carboxy methyl cellulose (NaCMC), are considerably lower than their critical micelle concentration (cmc). After the complete complexation, free micelles are formed at the apparent critical micelle concentration (acmc), which is slightly higher in polyelectrolyte aqueous solution than in pure water. Among the cationic surfactants (i.e., CTAB, TTAB, and DTAB), DTAB was found to have least interaction with NaCMC. Surfactants with longer tail size strongly favor the interaction, indicating the dependence of aggregation phenomenon on the structure, morphology, and tail length of the surfactant.      

Adsorption of Fe(III) from Aqueous Medium onto Glycine-Modified Chitosan Resin: Equilibrium and Kinetic Studies

The adsorption of Fe(III) onto glycine-modified chitosan (G@Chs) resin has been investigated. The parameters studied include the effects of pH, contact time, and initial metal ion concentrations by batch method. The optimal pH for the adsorption of Fe(III) was found to be 2.5. The results obtained from equilibrium adsorption studies are fitted in various adsorption models such as Langmuir and Freundlich, and each model parameter were evaluated. Kinetics and thermodynamic parameters of the adsorption process were also investigated. The maximum uptake was found to be 0.9 mmol g^?1 at 25°C.     

Stability of Dye Dispersions in the Presence of Various Surface Active Agents and Additives

Disperse dyes are hardly soluble in water. They are usually milled in the presence of large amounts of dispersing agents in the dye industry. The type and amount of these materials can affect the disperse ability of dyes in aqueous media. In this article, stability of prepared dye dispersions in the presence of various surface active agents and additives were investigated. In this respect, various dispersing agents such as Irgasol DAM, Asutol 644, Dispertane MF, and Irgasol P800 were used to prepare dye dispersions in milling stage. Furthermore, the formulations of dye dispersions were obtained by adding β-cyclodextrin, urea, and wetting agent. The dye dispersion quality was determined by its filtering property, turbidity, and centrifuging method. The obtained results proved the stability of dispersion containing of Irgasol DAM, wetting agent, and β-cyclodextrin as dispersing auxiliaries in dyeing process of disperse dye on polyester fabrics in high temperature method was the highest as compared to other dispersions. From the experimental results, it was found out that stability of prepared dispersions was improved by the presence of β-cyclodextrin. Also, utilization of β-cyclodextrin in formulations of dye dispersions caused to increasing of stability of dispersion in the dyeing of polyester fabrics.