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In this work, we have prepared water-soluble superparamgnetic iron oxide nanoparticles (SPIONs) coated with a dual responsive polymer for targeted delivery of anticancer hydrophobic drug (curcumin) and hyperthermia treatment. Herein, superparamagnetic mixed spinel (MnFe2O4) was used as a core material (15-20 nm) and modified with carboxymethyl cellulose (water-soluble component), folic acid (tagging agent), and dual responsive polymer (poly-N isopropylacrylamide-co-poly glutamic acid) by microwave radiation. Lower critical solution temperature (LCST) of the thermoresponsive copolymer was observed to be around 40 °C, which is appropriate for drug delivery. The polymer-SPIONs show high drug loading capacity (89%) with efficient and fast drug release at the desired pH (5.5) and temperature (40 °C) conditions. Along with this, the SPIONs show a very fast increase in temperature (45 °C in 2 min) when interacting with an external magnetic field, which is an effective and appropriate temperature for the localized hyperthermia treatment of cancer cells. The cytocompatibility of the curcumin loaded SPIONs was studied by the methyl thiazol tetrazolium bromide (MTT) assay, and cells were imaged by fluorescence microscopy. To explore the targeting behavior of curcumin loaded SPIONs, a simple magnetic capturing system (simulating a blood vessel) was constructed and it was found that ∼99% of the nanoparticle accumulated around the magnet in 2 min by traveling a distance of 30 cm. Along with this, to explore an entirely different aspect of the responsive polymer, its antibacterial activity toward an E. coli strain was also studied. It was found that responsive polymer is not harmful for normal or cancer cells but shows a good antibacterial property.

Oil recovery by water flooding from carbonate reservoirs is considered ineffective because of the capillary forces in naturally fractured oil-wet carbonate formations. Surfactant solutions are often recommended to enhance the oil recovery by both wettability alteration and reduction of interfacial tension (IFT). In this study, the effects of cationic surfactants from the trimethylammonium bromide (C n TAB) family, viz., C10TAB (BTAB), C15TAB (DTAB), C16TAB (TBAB), and C19TAB (CTAB), on the surface tension, IFT, and wettability alteration of a carbonate rock along with adsorption of the surfactant on the carbonate rock were investigated. Different analyses, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), and Fourier transform infrared spectroscopy (FTIR), were conducted to study the mechanism for wettability alteration of the oil-wet carbonate surface. Results demonstrated that, among the four surfactants used, C15TAB and C19TAB presented a better effect on reduction of the surface tension, IFT between oil and water, and wettability alteration of the oil-wet carbonate rock surface. Adsorption of surfactants on the carbonate rock was studied, and the results were analyzed by Langmuir and Freundlich models. A comparative study of FTIR analysis of crude oil and rock in the presence of different surfactants was performed to investigate the interactions between different phases.

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We report here the electrochemical behavior of quantum sized glutathione protected Au 25 nanoclusters and their use in electrochemical sensing. The Au 25 modified electrode was found to show excellent electrocatalytic activity towards the oxidation of ascorbic acid and dopamine over a wide linear range from 0.71 to 44.4 mM. The modified electrode exhibited pH dependent electrocatalytic activity, which was attributed to the consequence of electrostatic attraction/repulsion between the charged Au 25 clusters and the charged analytes at different pH. This result demonstrates the feasibility of enhancing the sensing selectivity among the charged analytes by controlling the charges on the clusters.