Synthesis of bimetallic nanoparticles loaded on to PNIPAM hybrid microgel and their catalytic activity

Abstract

This study was designed to preparecarboxyl-functionalized poly (N-isopropylacrylamide) PNIPAM microgels having excellent catalytic properties.Recently, researchers are trying to fabricate cost effective and efficient hybrid catalytic materials for the synthesis of nitrogenous compounds along with enhanced optical properties. For the same motive, synthesis of carboxyl-functionalized PNIPAM microgels was performed by using polymerization of soap-free emulsion of N-isopropyl acrylamide, which is NIPAM along with acrylic acid (AA). The thiol group was introduced through the imide bond mediated by carbodiimide, between carboxyl-functionalized microgels through carboxyl group and aminoethanethiol (AET). Copper, Palladium and Cu/Pd nanoparticles were incorporated successfully into thiol-functionalized PNIPAM microgels through metals thiol linkage. The synthesized microgels and hybrid encompassing metallic nanoparticles were characterized in detail by using Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron (XPS) and Fourier transformed infrared spectroscopy for structural interpretation. The thermal properties of the pure and hybrid microgels were inspected by TG analysis. The prepared nanocomposites PNIPAM-Cu, PNIPAM-Pd and PNIPAM-Cu/Pd exhibited decent catalytic properties for the degradation of 4-Nitrophenol and methylene blue, but the bimetallic Cu/Pd have remarkable catalytic properties. The catalytic reaction followed pseudo-first-order reaction with rate constants 0.223 min−1, 0.173 min−1 for 4-Nitrophenol and methylene blue in that order. In this study,we were able to establish that Cu/Pd hybrid is an efficient catalyst for 4-Nitrophenol and methylene blue as compared to its atomic analogue.

Dexmedetomidine does not compromise neuronal viability, synaptic connectivity, learning and memory in a rodent model

“…Sprague–Dawley rat frontal cortices were isolated and cultured as previously described 34 . Some cultures were treated with various concentrations of dexmedetomidine (10 mg; MilliporeSigma, St. Louis, MO, USA) (0.05 μM, 0.1 μM, 1 μM, 2.5 μM, 5 μM, or 10 μM) dissolved in culture media, whereas controls only had culture media.…”

“…The effects of DEX on neuronal viability were tested 3 days post-culture via the LIVE⁄DEAD Viability/Cytotoxicity Kit (Molecular Probes) as previously described 34 . In order to assess the effect at a later time point, we also analyzed the viability of the remaining alive cells at day seven post-exposure.…”

“…Fluorescence images were taken on an Olympus SD-OSR spinning-disk confocal microscope (100×/1.49 oil)) with a mounted incubator system (Olympus Corp.) and all imaging parameters were kept identical for each dish. Mitochondrial morphology was quantified as previously described 34 .…”

“…Immunofluorescent staining was performed to assess the impact of dexmedetomidine on neuronal cytoskeletal growth in neurons grown for 7 days post-culture. Fixation and staining were done as previously described for neurofilament antibody 34 . Cells were imaged on a Zeiss Axio Observer Z1 microscope (Zeiss Corp.) using a 20×/0.8 DICII objective.…”

“…A procedure similar to the one previously outlined was followed to evaluate the impact of DEX on synaptic network assembly in neurons grown for 7 days post-culture using synaptophysin and PSD-95 antibodies as previously described 34 . Cells were imaged on a Zeiss Axio Observer Z1 microscope (Zeiss Corp.) using a 63×/1.4 oil DICII objective 15–20 neurons per biological replicate (n = 8–10) were quantified.…”