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Thandapani, P., Aepuru, R., Beron, F., Mangalaraja, R. V., Varaprasad, K., Zabotto, F. L., et al. (2023). Multiferroic Electroactive Polymer Blend/Ferrite Nanocomposite Flexible Films for Cooling Devices. ACS Appl. Polym. Mater., 5(8), 5926–5936.
Abstract: In recent days, the interest toward the development ofmulticaloricmaterials for cooling application is increasing, whereas multiferroicmaterials would be the suitable alternative to the conventional refrigerants.To explore them, the poly(methyl methacrylate)/poly(vinylidenefluoride-co-hexafluoropropylene) (PMMA/PVDF-HFP) blend and PMMA/PVDF-HFP/Zn0.5Cu0.5Fe2O4 flexible multiferroicnanocomposite films were fabricated by the solution casting method.The structural analyses prove that the strong interfacial interactionbetween the PMMA/PVDF-HFP blend and the Zn0.5Cu0.5Fe2O4 (ZCF) through hydroxyl (-OH) andcarbonyl group bonding with PVDF-HFP enhanced the thermal stabilityand suppressed the electroactive & beta; phase from 67 to 62%. Experimentalresults show that 10 wt % of superparamagnetic ZCF nanoparticles witha particle size of 6.8 nm induced both the magnetocaloric and magnetoelectriceffects in a nonmagnetic PMMA/PVDF-HFP ferroelectric matrix at roomtemperature. A set of isothermal magnetization curves were recordedin the magnetic field strength of 0-40 kOe and a temperaturerange of 2-400 K. The maximum magnetic entropy changes (& UDelta;S (M)) of -0.69 J & BULL;kg(-1) K-1 of ZCF nanoparticles and -0.094 J & BULL;kg(-1) K-1 of PMMA/PVDF-HFP/ZCF nanocompositesshowed an interesting table-like flat variation in the temperaturerange of 100-400 K as a function of the magnetic field. Thesamples display a large temperature span with a relative cooling power of 293 and 40 J & BULL;kg(-1) for ZCF and PMMA/PVDF-HFP/ZCF,respectively. The magnetoelectric effect of the PMMA/PVDF-HFP/ZCFcomposite was proved, but it generated only 1.42 mV/m & BULL;Oe in theapplied field of 5 kOe. Hence, the entropy change of the present nanocompositewas only due to the magnetocaloric effect, where the magnetoelectriccross-coupling coefficient was negligible. The multicaloric effectcould be established if the nanocomposite showed a larger magnetoelectriccross-coupling in addition to the magnetocaloric effect. This approachprovides the research findings in functional multiferroic polymernanocomposites for miniaturized cooling devices.
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Valle, H., Palao-Suay, R., Aguilar, M. R., Lerma, T. A., Palencia, M., Mangalaraja, R. V., et al. (2023). Nanocarrier of α-Tocopheryl Succinate Based on a Copolymer Derivative of (4,7-dichloroquinolin-2-yl)methanol and Its Cytotoxicity against a Breast Cancer Cell Line. Polymers, 15(22), 4342.
Abstract: In order to improve the water solubility and, therefore, bioavailability and therapeutic activity of anticancer hydrophobic drug alpha-tocopherol succinate (alpha-TOS), in this work, copolymers were synthesized via free radicals from QMES (1-[4,7-dichloroquinolin-2-ylmethyl]-4-methacryloyloxyethyl succinate) and VP (N-vinyl-2-pirrolidone) using different molar ratios, and were used to nanoencapsulate and deliver alpha-TOS into cancer cells MCF-7. QMES monomer was chosen because the QMES pendant group in the polymer tends to hydrolyze to form free 4,7-dichloro-2-quinolinemethanol (QOH), which also, like alpha-TOS, exhibit anti-proliferative effects on cancerous cells. From the QMES-VP 30:70 (QMES-30) and 40:60 (QMES-40) copolymers obtained, it was possible to prepare aqueous suspensions of empty nanoparticles (NPs) loaded with alpha-TOS by nanoprecipitation. The diameter and encapsulation efficiency (%EE) of the QMES-30 NPs loaded with alpha-TOS were 128.6 nm and 52%; while for the QMES-40 NPs loaded with alpha-TOS, they were 148.8 nm and 65%. The results of the AlamarBlue assay at 72 h of treatment show that empty QMES-30 NPs (without alpha-TOS) produced a marked cytotoxic effect on MCF-7 breast cancer cells, corresponding to an IC50 value of 0.043 mg mL-1, and importantly, they did not exhibit cytotoxicity against healthy HUVEC cells. Furthermore, NP-QMES-40 loaded with alpha-TOS were cytotoxic with an IC50 value of 0.076 mg mL-1, demonstrating a progressive release of alpha-TOS; however, the latter nanoparticles were also cytotoxic to healthy cells in the range of the assayed concentrations. These results contribute to the search for a new polymeric nanocarrier of QOH, alpha-TOS or other hydrophobic drugs for the treatment of cancer or others diseases treatable with these drugs.
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Vinoth, V., Kaimal, R., Selvamani, M., Michael, R., Pugazhenthiran, N., Mangalaraja, R. V., et al. (2023). Synergistic impact of nanoarchitectured GQDs-AgNCs(APTS) modified glassy carbon electrode in the electrochemical detection of guanine and adenine. J. Electroanal. Chem., 934, 117302.
Abstract: In this work, a facile green approach for the synthesis of graphene quantum dots (GQDs) embedded on silicate network silver nanocrystals (GQDs-AgNCs(APTS)) is reported. Moreover, glassy carbon-GC electrodes were mod-ified with the prepared nanocomposite containing graphene quantum dots supported on silver nanocrystals (GQDs-AgNCs(APTS)) and applied for simultaneous detection of guanine (GA) and adenine (AD). The chemically modified electrode was assessed during the determination of purine bases by cyclic voltammetry-CV and dif-ferential pulse voltammetry-DPV. The incorporation of GQDs-AgNCs(APTS) nanocomposites over the surface of the GC electrode considerably enhances the anodic peak currents and decreases the adenine and guanine peak potentials. Compared to other electrodes, GQDs-AgNCs(APTS)/GC improved the electrochemical behavior towards the detection of adenine and guanine. At optimal conditions, calibration curves were obtained by DPV being linear in the range of 0.1-6.0 mu M and 0.1-5.0 mu M for guanine and adenine, respectively. The detec-tion limits of both guanine and adenine were estimated as 0.1 mu M. Additionally, interferences analyses were performed on the existence of other interferent compounds. Furthermore, the method developed for the iden-tification of GA and AD was proved using fish sperm DNA samples.
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