RSC Advances

Li, Yeping; Xu, Jingbo; Xu, Yun; Huang, Liying; Wang, Junli; Cheng, Xiaonong

doi: 10.1039/c5ra02933cpmid: N/A

The objective of the study is to describe a new approach of combining quantum dots into chitosan as an anti-cancer drug carrier. Novel chitosan–ZnSe/ZnS (CS–ZnSe/ZnS) nanoparticles were synthesized by a one-step ionic gelation technique, with ZnSe/ZnS quantum dots (ZnSe/ZnS QDs) as cross-linking agent and for fluorescent labeling. The approach not only avoids the use of emulsifiers and chemical cross-linking agents but also prevents the possibility of damage to drugs. The fluorescent CS–ZnSe/ZnS nanoparticles were about 100–500 nm in size and stable in a physiological environment. Low cytotoxicity was ensured by investigation with mouse lung carcinoma cells. The cell viability remained 99% when the concentration of CS–ZnSe/ZnS nanoparticles increased to 200 μg mL−1. In the in vitro drug release experiment, 5-fluorouracil (5-Fu) loaded within CS–ZnSe/ZnS nanoparticles had more preferable sustained-release performance and longer equilibrium time compared with that of the pure 5-Fu. The fluorescent CS–ZnSe/ZnS nanoparticles are expected to be used for biological fluorescent labeling and drug carriers.

Kundu, Debasree; Hazra, Chinmay; Chaudhari, Ambalal

doi: 10.1039/c5ra02450apmid: N/A

2,4-Dinitrotoluene (2,4-DNT), a major by-product during the synthesis of 2,4,6-trinitrotoluene, is widely used as a gelatinizing, waterproofing and plasticizing agent in explosives and propellants. Since DNTs and its metabolites exhibit toxicity to human beings, fish, algae and microorganisms, they are treated as priority pollutant in several countries. This study describes the biodegradation of 2,4-DNT in batch mode by Rhodococcus pyridinivorans NT2 in the range of 0.5–2 mM. At initial concentration of 0.54 mM, degradation kinetics were described well by zero-order model. However, modeling of the biodegradation at higher concentrations indicated that the Andrews–Haldane model predicts the experimental data fairly well. During growth and biodegradation, changes in saturated/unsaturated ratio of fatty acids, total cyclo fatty acids, and the ratio of anteiso:iso-branching were observed. This was accompanied by increased cell size, alternation in enzymatic and non-enzymatic antioxidant defense systems, accumulation of biosurfactants and carotenoids. Biodegradation of 2,4-DNT by this strain proceeded through a pathway involving intermediates such as 2-amino-4-nitrotoluene and 2,4-diaminotoluene. The strain NT2 harbored plasmid that was found to be associated with biodegradation.

Liu, Shaoqing; Gong, Weiyu; Dong, Yanmei; Hu, Qing; Chen, Xiaofeng; Gao, Xuejun

doi: 10.1039/c5ra03786gpmid: N/A

This study investigated the effects of novel submicron bioactive glass (sm-BG) particles on in vitro osteogenesis and compared them to those of microscale bioactive glass (m-BG) particles. The ability of sm-BG particles to generate precipitates on their surface in the presence of simulated body fluid (SBF) was examined, and the effect of sm-BG particles on in vitro osteogenesis was evaluated by culturing human osteoblast-like osteosarcoma (MG-63) cells on particle-coated plates. It was found that sm-BG induced formation of precipitates after incubation for 24 hours in SBF. Compared with m-BG, sm-BG particles better promoted MG-63 cell adhesion and they induced expression of the ALP, RUNX2 and COL1 genes at an earlier stage and to a greater degree. This study demonstrates that submicron bioactive glass particles possess a high capacity for precipitates formation in SBF and improved osteogenic properties when compared to microscale BG particles.

Renuka, N. K.; Harsha, N.; Divya, T.

doi: 10.1039/c5ra01161bpmid: N/A

Herein we present the exceptionally high oxygen buffer action of ceria quantum dots of size 3.7 nm. Ceria nanoparticles were obtained via a facile ammonia precipitation route, and were characterized using TEM, XRD, BET surface area analysis, XPS analysis and TPR study using H2 as the probe molecule. A supercharging effect that leads to low temperature oxygen release is observed in these ultra-fine ceria particles. Existence of under stoichiometry in the ceria nanostructures with practically no oxygen vacancies has been substantiated with experimental proof.

Tomak, A.; Zareie, H. M.

doi: 10.1039/c5ra03240gpmid: N/A

A simple method has been described for synthesizing gold nanorods (GNRs) encapsulated bubbles in a controlled manner. The method involves the use of nitrogen gas in the seed-mediated synthesis method routinely used for synthesis of GNRs. Control over the morphology of the nanostructures was achieved by nitrogen gas flow. The synthesized structures were examined by UV-Vis Spectroscopy, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). New structures of this type could conceivably serve as plasmonic biosensors, nanodevices and photothermal theranostics with dual modality imaging functionality.

Garg, Yuvraj; Gahalawat, Suraksha; Pandey, Satyendra Kumar

doi: 10.1039/c5ra05987apmid: N/A

A simple and highly efficient synthetic approach to enantiopure 2-alkyl substituted tetrahydroquinoline 1 skeleton from aldehydes as starting materials and its application to the total synthesis of (+)-angustureine 2 is described. Key transformations include proline catalyzed aminoxylation, Corey–Fuchs protocol, Sonogashira coupling and intramolecular Mitsunobu reactions.

Larsen, Lachlan J.; Shearer, Cameron J.; Ellis, Amanda V.; Shapter, Joseph G.

doi: 10.1039/c5ra03965gpmid: N/A

Here, surfactant-assisted exfoliated graphene (SAEG) has been used to make transparent conducting graphene films which for the first time were used to make SAEG–silicon Schottky junctions for photovoltaics. The graphene films were characterised using UV-Vis spectroscopy, Raman spectroscopy, atomic force microscopy and four point probe sheet resistance measurements. The effects of film thickness, thermal annealing and chemical doping of the graphene films on the power conversion efficiency (PCE) of the cells were investigated. Mild annealing of thickness optimised films resulted in a doubling of the PCE. Additionally, chemical doping resulted in a further 300% increase of the peak PCE. These results indicate that SAEG has the potential to compete with chemical vapour deposited graphene in graphene–silicon Schottky junction applications.

Carré, Gaëlle; Garnier, Laurent; Moeller-Siegert, Janina; Gies, Jean-Pierre; Keller, Valérie; André, Philippe; Keller, Nicolas

doi: 10.1039/c5ra05541epmid: N/A

The sprayed layer-by-layer assembly of TiO2 photocatalyst has been efficiently used for functionalizing polyester textiles and elaborating solar light active antibacterial textiles. Polyethylenimine (PEI) and polyanionic poly(styrene sulfonate) (PSS) polyelectrolytes have been used as polycation and polyanion layers, in alternation with dispersions of negatively- and positively-charged TiO2 particles, respectively. A synergistic effect resulting from both biocidal photocatalytic activity of TiO2 layers and biocidal activity of PEI layers within the multilayer system was put forward for explaining the high self-decontaminating activity of (PEI/TiO2)n functionalized textiles, 5 log of cell viability reduction being achieved with a single TiO2 layer at 50 μg cm−2. The sole solar light photocatalytic antibacterial activity of multilayer textiles was determined by masking the biocidal activity of PEI layers through the controlled assembly of PEI/(PSS/TiO2)n multilayers.

Lai, Ching-Chang; Lo, Chieh-Tsung

doi: 10.1039/c5ra04284dpmid: N/A

The effect of oxygen-plasma treatment on the capacitive behavior of electrospun carbon nanofibers is investigated. The plasma-modified fibers are enriched in oxygen functionalities, resulting in increased fiber wettability. Moreover, the plasma-treated nanofibers exhibit a specific capacitance of 377.0 F g−1, which is more than twice that of the nontreated nanofibers.

Hou, Jianhua; Duan, Qian; Qin, Jieming; Shen, Xiande; Zhao, Jianxun; Liang, Qingcheng; Jiang, Dayong; Gao, Shang

doi: 10.1039/c5ra02724apmid: N/A

We adopted a new “electronic” strategy that is adding two electrons into the dz2 orbital of the central M atom to form a lone pair, which is in contrast to the Hoffmann’s “electronic” strategy that is delocalizing the lone pair on the center atom, to turn the bowl-type MBnHn0/+ (M = Cr and Mn; n = 6 and 7) clusters into planar wheel-type M©BnHn2−/− clusters. Their isoelectronic neutral clusters, Fe©B6H6 and Fe©B7H7, also possess planar wheel-type structures. The large binding energy, vertical ionization potential, and vertical electron affinity indicate that the planar wheel-type M©BnHn2−/− clusters are chemically stable. This study may open up a new area in coordination chemistry for planar hexa- and hepta-coordinate transition metal and we expect further experimental explorations of synthesis and potential applications.