RSC Advances

Majumdar, Swapan; Hossain, Jewel; Natarajan, Ramalingam; Banerjee, Ashish K.; Maiti, Dilip K.

doi: 10.1039/c5ra22436epmid: N/A

The highly selective synthesis of phthalate templated bridged isoxazoline macrocyclic lactones is demonstrated using readily accessible carbohydrate precursors via intramolecular nitrile oxide–alkene cycloaddition. The structures of the macrocycles were established by 2D NMR as well as X-ray diffraction study. The orientation of the bridged isoxazoline ring is dependent on the distance between the 1,3-dipole and dipolarophile. The macrocycles are amenable to further transformations to higher amino sugars by sequential removal of the phthalate template and reductive cleavage of the isoxazoline moiety.

Xu, Guohe; Li, Jie; Deng, Jinni; Yin, Lv; Zheng, Zhaohui; Ding, Xiaobin

doi: 10.1039/c5ra23066gpmid: N/A

The paper proposed an approach to construct a novel kind of rhythmic assembly system with fireflies' function through combining a pH oscillator based on the hydrogen peroxide/dithionite system with pH-responsive dynamic covalent bonds composed by phenylboronic acid and alizarin red S.

Yang, Deming; Xu, Shanshan; Dong, Shuilang; Liu, Jiachen; Guo, Anran; Yan, Xiao; Hou, Feng

doi: 10.1039/c5ra21609epmid: N/A

Continuous Fe nanoparticles (NPs)/carbon nanotube (CNTs) composite films have been fabricated with the CVD gas flow reaction using ferrocene as a catalyst and ethanol as a carbon precursor. The as-spun Fe NPs/CNTs films are converted to Fe2O3 NPs/CNTs films by an annealing process in air at a temperature of 500 °C. The as-prepared Fe2O3 NPs/CNTs films are still highly flexible. Scanning electron microscopy (SEM) and transmission electron microscopy observations reveal the Fe2O3 NPs are homogeneously bonded with the CNT network. In addition, the flexible and conductive 3D CNTs networks endow the as-synthesized composite with increased electrical conductivity and mechanical stability. As a result, the as-synthesized flexible and transferrable composite films deliver an initial reversible capacity of 985.8 mA h g−1 at a current density of 30 mA g−1, and maintain a high reversible capacity of 392.4 mA h g−1 even at a current density up to 3 A g−1. Meanwhile, Fe2O3 NPs/CNTs films exhibit an excellent cycling performance with a reversible capacity of 375.5 mA h g−1 after 800 cycles at a current density of 3 A g−1.

Zhang, Yong; Ji, Ye; Wang, Ziying; Liu, Sen; Zhang, Tong

doi: 10.1039/c5ra24727fpmid: N/A

Reduced graphene oxide–carbon nanotube (rGO–CNT) hybrids have been synthesized by electrodeposition of GO stabilized CNT using indium tin oxide (ITO) as working electrode, followed by electrochemical reduction of GO–CNT into rGO–CNT on the surface of ITO. The combined characterizations of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses have been used to examine the structure of rGO–CNT hybrids, indicating the successful preparation of hybrids. More importantly, compared with the bare ITO and rGO/ITO electrodes, the rGO–CNT/ITO electrode exhibits excellent sensing performance for electrochemical detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA), leading to a high-performance electrochemical sensor for simultaneous detection of AA, DA and UA. The linear detection ranges of the AA, DA and UA sensors based on rGO–CNT hybrids were estimated to be 10–200 μM, 0.2–8.0 μM and 0.2–16.0 μM, and the detection limits were 5.31 μM, 0.04 μM and 0.17 μM, respectively.

Zhou, Huaijuan; Li, Jinhua; Bao, Shanhu; Wang, Donghui; Liu, Xuanyong; Jin, Ping

doi: 10.1039/c5ra22582epmid: N/A

A thermochromic vanadium dioxide (VO2) film holds great promise for intelligent windows owing to marvelous semiconductor-metal transitions (SMT), an active response to external temperature stimuli and near-infrared irradiation. To date, however, its potential biological effect on human cells has not been well characterized. In this work, homogeneous high quality VO2 films with different thicknesses (30, 80, 120 nm) were prepared on a quartz glass substrate. Afterwards, for the first time, we demonstrate the time-dependent and dose-dependent cytotoxicity of the VO2 film to human cells. Speciation analysis by 51V NMR spectra and surface zeta potentials revealed the formation of vanadate(+5) and ADPV, an analogue of ATP. On the basis of energy metabolism or bioenergetics, a plausible hypothesis, i.e., “ATP dyssynthesis”, is proposed here to elucidate the potential toxicity mechanism of the VO2 nanomaterial via vanadate-phosphate antagonism including two steps: (i) vanadate speciation from VO2 surface chemistry; (ii) vanadate disturbing ATP synthesis as a phosphate analogue. ATP stores energy to carry out various life processes; once its synthesis is hindered, vital movement will be impaired. From the perspective of surface modification and bioactivation, some practical methods are recommended to compensate for the potential cytotoxicity of the VO2 material. We expect this work can stimulate scientific interest to search for more versatile material design strategies to balance the energy-saving efficiency and environmental safety of VO2 intelligent window coatings.

Ma, Yue; Wang, Xue; Zong, Shan; Zhang, Zhiyun; Xie, Zhigang; Huang, Yubin; Yue, Ying; Liu, Shi; Jing, Xiabin

doi: 10.1039/c5ra17230fpmid: N/A

Locoregional recurrence of cervical cancer following surgical resection remains a severe clinical problem. To reduce tumor replase rate with more efficacy and safety, local combination chemotherapy may has advantages over mono-chemotherapy or systemic chemotherapy. The aim of this study was to evaluate the efficacy of electrospun nanofibers co-loaded with cisplatin and curcumin to prevent local recurrence of cervical cancer after surgery. From in vitro tests, the combination of cisplatin and curcumin achieved a synergetic effect in growth inhibition and apoptosis induction of HeLa cells. From in vivo trails, local implantation of nanofibers enabled both drugs to be highly accumulated at the surgical site with an optimum concentration ratio between the two drugs. When used in the prevention of U14 cervical cancer recurrence in mice, nanofiber-based local combination chemotherapy was more effective and less toxic than systemic combination chemotherapy, indicating its great clinical potential in the future.

Li, Jun; Liu, Bang-Gui

doi: 10.1039/c5ra19582apmid: N/A

It has been experimentally established that magnetic adatoms on surfaces can be arranged to form antiferromagnetic quantum spin chains with strong uniaxial anisotropy and Neel states in such spin systems can be used to realize information storage. Here, we investigate eigenstates, quantum spin dynamics, and life times of Neel states in short antiferromagnetic quantum spin chains with strong uniaxial anisotropy on the basis of numerical exact diagonalization method. We show rigorously that as long as the uniaxial anisotropy is very strong, the ground state and the first excitation state, being nearly degenerate, are safely separated from the other states and thus dominate the quantum dynamics of the Neel states. Through further numerical analysis, we achieve a powerful life-time expression of the Neel states for arbitrary spin and model parameters. It is interesting that for the famous Fe adatom chains on Cu2N surface, 14 or 16 Fe adatoms are enough to obtain a practical long life-time for Neel state storage of information. These should be applicable to other similar antiferromagnetic spin systems for atomic-scale antiferromagnetic spintronics.

Huang, Binyan; Liu, Yunguo; Li, Bin; Zeng, Guangming; Hu, Xinjiang; Zheng, Bohong; Li, Tingting; Jiang, Luhua; Tan, Xiaofei; Zhou, Lu

doi: 10.1039/c5ra22862jpmid: N/A

A novel graphene oxide composite, namely Fe3O4@SiO2@ chitosan/GO nanocomposite (MSCG) was synthesized for decontamination of Cr(vi) from aqueous solution. High-resolution transmission electron microscopy revealed a core@double-shell structure of the nanoparticles with iron oxide as the core, silica as the inner shell and chitosan as the outer shell. The characteristic results of Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM) and X-ray diffraction (XRD) showed that the Fe3O4@SiO2@chitosan particles were successfully assembled on the surface of the GO layers. The adsorption kinetics followed the pseudo-second-order model and the novel MSCG adsorbent exhibited better Cr(vi) removal efficiency in solutions at low pH. Thermodynamic parameters revealed that the sorption reaction was endothermic and spontaneous. Moreover, the adsorption capacity was about 90% of the initial saturation adsorption capacity after being used four times. By using a permanent magnet, the recycling process of both the MSCG adsorbents and the adsorbed Cr(vi) is more economically sustainable. These results suggest that MSCG is a potential and suitable candidate for the preconcentration and separation of Cr(vi) from wastewater and for the deep-purification of polluted water.

Wang, Ping; Li, Zhongfeng; Cao, Shengli; Rao, Honghua

doi: 10.1039/c5ra24634bpmid: N/A

The first intermolecular addition reaction of aryloxyl radicals to CC bonds was disclosed, which can afford biologically important chromone scaffolds via a PhNMe3I-catalyzed direct coupling of readily available salicylaldehydes and activated internal alkynes in only one step, and can tolerate a range of catalytically reactive functional groups.

Feng, Xueling; Zhang, Kaihuan; Hempenius, Mark A.; Vancso, G. Julius

doi: 10.1039/c5ra21256apmid: N/A

Macromolecules containing metals combine the processing advantages of polymers with the functionality offered by the metal centers. This review outlines the progress and recent developments in the area of electrochemical chemo/biosensors that are based on organometallic polymers. We focus on materials in which the metal centers provide function, allowing these materials to be used in electrochemical sensing applications based on various transduction mechanisms. Examples of chemo/biosensors featuring organometallic polymers that possess Fe, Os, Co and Ru are discussed.