Fabrication of a Molecularly-Imprinted-Polymer-Based Graphene Oxide Nanocomposite for Electrochemical Sensing of New Psychoactive Substances.

As new psychoactive substances (commonly known as "the third generation drugs") have characteristics such as short-term emergence, rapid updating, and great social harmfulness, there is a large gap in the development of their detection methods. Herein, graphite oxide (GO) was first prepared and immobilized with a reversible addition-fragmentation chain transfer (RAFT) agent, then a new psychoactive substance (4-MEC) was chosen as a template, and then the surface RAFT polymerization of methacrylamide (MAAM) was carried out by using azobisisobutyronitrile (AIBN) as an initiator and divinylbenzene (DVB) as a cross-linker. After the removal of the embedded template, graphene oxide modified by molecularly imprinted polymers (GO-MIPs) was finally obtained. Owing to the specific imprinted cavities for 4-MEC, the satisfactory selectivity and stability of the GO-MIP nanocomposite have been demonstrated. The GO-MIP nanocomposite was then used to fabricate the electrochemical sensor, which displayed a high selectivity in detecting 4-MEC over a linear concentration range between 5 and 60 µg mL-1 with a detection limit of 0.438 µg mL-1. As a result, the GO-MIPs sensor developed an accurate, efficient, convenient, and sensitive method for public security departments to detect illicit drugs and new psychoactive substances.

Membrane Nanopores Induced by Nanotoroids via an Insertion and Pore-Forming Pathway.

The formation of membrane nanopores is one of the crucial activities of cells and has attracted considerable attention. However, the understanding of their types and mechanisms is still limited. Herein, we report a novel nanopore formation phenomenon achieved through the insertion of polymeric nanotoroids into the cellular membrane. As revealed by theoretical simulations, the nanotoroid can embed in the membrane, leaving a nanopore on the cell. The through-the-cavity wrapping of lipids is critical for the retention of the nanotoroid in the membrane, which is attributed to both a relatively large inner cavity of the nanotoroid and a moderate attraction between the nanotoroid and membrane lipids. Under the guidance of the simulation predictions, experiments using polypeptide toroids as pore-forming agents were performed, confirming the unique biophysical phenomenon. This work demonstrates a distinctive pore-forming pathway, deepens the understanding of the membrane nanopore phenomenon, and assists in the design of advanced pore-forming materials.

Programmable Morphology Evolution of Rod-Coil-Rod Block Copolymer Assemblies Induced by Variation of Chain Ordering.

Morphology transition of block copolymer assemblies in response to external stimuli has attracted considerable attention. However, our knowledge about the mechanism of such a transition is still limited, especially for rod-coil block copolymers. Here, we report a programmable morphology evolution of assemblies induced by variation of chain ordering for rod-coil-rod triblock copolymers. A sequence of morphology transition from ellipsoids to disks, bowls, and vesicles is observed by increasing the solution temperature. At high temperatures, the mobility of the rod chain increases and the rigidity of the rod chain decreases. This gives rise to an ellipsoid-to-vesicle morphology transition. Dissipative particle dynamics theoretical simulations were performed to reveal the mechanism of this morphology transition process. It was found that the increase of rod chain mobility and the decrease of rod chain rigidity induce a decrease of chain ordering of rod blocks as temperature increases, which results in an ellipsoid-to-vesicle morphology transition. The gained information can guide the construction of nanoassemblies based on the rod-coil block copolymers.

Synthesis, characterization, and evaluation of selective molecularly imprinted polymers for the fast determination of synthetic cathinones.

As a kind of new psychoactive substance (NPS), synthetic cathinones have drawn great worldwide attention. In this study, molecularly imprinted polymers (MIPs), as adsorbents for the extraction and determination of 4-methyldimethcathinone (4-MDMC), were first synthesized by coprecipitation polymerization. The physicochemical analyses of MIPs were successfully performed by XRD, FTIR, FESEM and TGA techniques. Furthermore, rebinding properties of temperature and pH dependence, and selectivity and reusability tests for MIPs and non-imprinted polymers (NIPs) were performed using an ultraviolet-visible spectrometer (UV-vis). The obtained results indicate that the imprinting efficiency has strong dependence on temperature and pH, and the optimal adsorption for targets is achieved under the condition of 318 K and pH = 6.0. This means that the combination between the polymers and 4-MDMC is a strong spontaneous and endothermic process. Compared with NIPs, MIPs exhibit prominent adsorption capacity (Q e = 9.77 mg g-1, 318 K). The selectivity coefficients (k) of MIPs for 4-MDMC, methylenedioxypentedrone (ßk-MBDP), 4-ethylmethcathinone (4-EMC), methoxetamine (MXE) and tetrahydrofuranylfentanyl (THF-F) were found to be 1.70, 3.49, 7.14 and 5.82, respectively. Moreover, it was found that the adsorption equilibrium was achieved within 30 min. The aim of this work is the simple synthesis of MIPs and the optimal performance of the molecular recognition of 4-MDMC. Moreover, the synthesized MIPs can be easily regenerated and repeatedly used with negligible loss of efficiency (only 9.94% loss after six times adsorption-desorption tests). Satisfying recoveries in the range of 69.3-78.9% indicate that MIPs have good applicability for analyte removal from urine samples. Ultimately, this material shows great promise for the rapid extraction and separation of synthetic cathinones, which are dissolved in the liquid for the field of criminal sciences.

Self-assembly and stimuli-responsive behaviours of side-chain liquid crystalline copolymers: a dissipative particle dynamics simulation approach.

We conducted a dissipative particle dynamics simulation to explore the self-assembly behaviours of side-chain liquid crystalline copolymers in solvents poor for comb blocks. Our results show that the copolymers are able to self-assemble into various aggregates such as micelles and vesicles, and especially into deformed structures such as rectangle cylinders. The morphology of the aggregates depends on the concentration of copolymers and a series of structural parameters such as the length of the coil blocks. Three kinds of morphology diagrams are mapped out to gain insight into the effect of these parameters on the self-assembly behaviours. Moreover, the aggregate structures such as the spatial arrangement of the rigid side chain are analysed, and it was found that the interfaces of the aggregates are greatly influenced by the packing of the side chains. We also investigated the influence of the rod-to-coil conformation transition of side chains on the self-assembly, motivated by stimuli-responsive polymer systems. A transformation from a disk-like structure to a vesicle was observed as the rod-to-coil conformation transition occurs. A comparison between the available experimental observations and the simulation results is made, and agreement is achieved.

Designed formation of Co3O4/ZnCo2O4/CuO hollow polyhedral nanocages derived from zeolitic imidazolate framework-67 for high-performance supercapacitors.

Zeolitic imidazolate frameworks have stimulated great attention due to their potential applications in energy storage, catalysis, gas sensing, drug delivery etc. In this paper, the three-dimensional porous nanomaterial Co3O4/ZnCo2O4/CuO with hollow polyhedral nanocage structures and highly enhanced electrochemical performances was synthesized successfully by a zeolitic imidazolate framework-67 route. The composites hold the shape of the ZIF-67 templates well and the shell has multiple compositions. In the process, we first synthesized the nanostructure hydroxide precursors and then transformed them into the corresponding metal oxide composites by thermal annealing in air. In addition, the mass ratio of Zn to Cu in this material is discussed and optimized. We found that when the mass ratio is 3, the composite material has better electrochemical properties. When applied as an electrode material, Co3O4/ZnCo2O4/CuO-1 shows enhanced pseudocapacitive properties and good cycling stability compared with Co3O4/ZnCo2O4, Co3O4/CuO and Co3O4/ZnCo2O4/CuO-2, and Co3O4/ZnCo2O4/CuO-3. The assembled Co3O4/ZnCo2O4/CuO-1//AC hybrid device can be reversibly cycled in a large potential range of 0-1.6 V and can deliver a high energy density of 35.82 W h kg-1 as well as the maximum power density of 4799.25 W kg-1.

Antimicrobial Activity of Extracts of the Oyster Culinary Medicinal Mushroom Pleurotus ostreatus (Higher Basidiomycetes) and Identification of a New Antimicrobial Compound.

Pleurotus ostreatus is an edible mushroom that also has high medicinal values. In this study, P. ostreatus was tested for its ability to inhibit the growth of fungi and bacteria. The freeze-dried fruiting body, broth from submerged culture, and mycelial biomass of P. ostreatus were extracted using alcohols and water as solvents. The extracts were then tested for their antimicrobial activity against the growth of fungi and bacteria. It was observed that the water extract from fruiting bodies had the strongest effect in inhibiting the growth of most fungi. The most sensitive test microfungi to the inhibition were Candida albicans, Cryptococcus humicola, and Trichosporon cutaneum, and the most sensitive test bacteria were Staphylococcus aureus followed by Escherichia coli. Water extracts from culture broth or mycelial biomass were moderately inhibitive to the growth of fungi and bacteria. The alcohol-based solvents from all samples had much less antimicrobial activity against most test microorganisms. An antimicrobial compound was purified from the water extracts of fruiting bodies with Sephadex G 100 column chromatography and characterized by infrared absorption spectrum (IR), nuclear magnetic resonance (NMR), and mass spectroscopic analysis. We have identified this compound to be 3-(2-aminopheny1thio)-3-hydroxypropanoic acid. This purified compound had a minimum inhibitory concentration of 30 µg/mL and 20 µg/mL against the growth of fungi and bacteria, respectively.

Medicinal Mushroom Extracts Possess Differential Antioxidant Activity and Cytotoxicity to Cancer Cells.

Many species of edible mushrooms are known to contain a wide array of compounds with high nutritional and medicinal values. However, these values vary widely among mushroom species because of the wide diversity of compounds with different solubilities to solvents used in extraction. We report here the comparison of antioxidant activity and cytotoxicity against cancer cells in extracts of Pleurotus ostreatus, P. sajor-caju, Agaricus campestris, and A. bisporus from 7 different solvents, including water, ethanol, ethyl acetate, acetone, chloroform, hexane, and petroleum ether. The extracts were analyzed for their antioxidant activities using the % DPPH (2,2-diphenyl-1-picrylhydrazylhydrate) scavenging activity method. Our results revealed that the water extracts exhibited the highest % DPPH scavenging activity in comparison to all other solvent extracts. The highest value was obtained from the water extract of P. sajor-caju (78.1%), and the lowest one was from the hexane extract of A. bisporus (0.8%). In general, extracts from nonpolar solvents exhibited much lower antioxidant activities than those from polar solvents. The cytotoxic effects of these extracts were evaluated using 2 cancer cell lines of larynx carcinoma (HEp-2) and breast carcinoma (MCF-7). When added into Hep-2 cells, the hexane extracts from P. ostreatus, P. sajor-caju, A. bisporus, and A. campestris yielded the highest IC50 values of 1.7 ± 1.56, 2.1 ± 2.82, 4.4 ± 1.71, and 2.2 ± 1.34 µg/mL, respectively, in comparison to all other solvent extracts. Similar IC50 values were obtained when the MCF-2 cancer cells were tested, suggesting that hexane is the preferred solvent to extract the anticancer compounds from these mushrooms. Our results also indicated that extracts from solvents with nonpolar or intermediate polarity were more potent than those with high polarity in their cytotoxicity against cancer cells, and extracts from different mushrooms by the same solvent possessed varied degrees of cytotoxicity.

In vitro propagation of Gentiana scabra Bunge - an important medicinal plant in the Chinese system of medicines.

BACKGROUND: Gentiana scabra Bunge commonly known as 'Long dan cao' in China has been used in traditional Chinese medicines for more than 2000 years. Dry roots and rhizome of the herb have been used for the treatment of inflammation, anorexia, indigestion and gastric infections. Iridoids and secoiridoids are the main bioactive compounds which attribute to the pharmacological properties of this plant. The species is difficult to mass propagate by seed due to the low percentage of germination and limited dormancy period. Wild populations in some locations are considered to be in the endangered category due to over exploitation. RESULTS: In the present study, we report an efficient micropropagation system. Shoot apices of six weeks old in vitro grown G. scabra plants were used as explants for the in vitro propagation. Induction of multiple shoots (9.1/explant) was achieved on the culture of shoot apices on half strength Murashige and Skoog's basal medium (MSBM) containing 2.0 mg/L-1 6-benzylaminopurine (BA), 3% sucrose and 0.9% Difco agar. In vitro shoots induced profuse rooting on half strength of MSBM supplemented with 0.1 mg/L-1 1-naphthaleneacetic acid (NAA), 3% sucrose and 0.3% gelrite. A two-stage ventilation closure procedure during the in vitro culture, and transparent sachet technique enhanced the survival rate of G. scabra plantlets to 96% in the greenhouse. Tissue culture plants flowered after 5 months of transfer to pots. CONCLUSIONS: A simple and an efficient in vitro propagation protocol of Gentiana scabra Bunge by optimizing the medium composition and ventilation closure treatments has been developed. The protocol can be very useful in germplasm conservation and commercial cultivation of G. scabra plants.

Freeze-dried microalgae of Nannochloropsis oculata improve soybean oil's oxidative stability.

Marine microalga Nannochloropsis oculata possesses nutrients valuable for human health. In this study, we added freeze-dried N. oculata powder to soybean oil and observed a remarkable inhibition in oil oxidation. The amount of microalgae powder added was positively correlated to the increase in oil stability. The addition of 5.0 % (w/w) microalgae powder increased the oil stability index (OSI) values of soybean oil more than twofold at the tested temperatures 120 and 130 °C. N. oculata contains high levels of both phenolic compounds and α-tocopherols that could be the contributors to such an increase of the OSI. Two methods were conducted to assay the active ingredients released from microalgae: one employed three solvent systems to extract the microalgae and the other was the soybean oil added with microalgae. Analyses of free radical scavenging and reducing power suggested that the phenolic compounds dominated the antioxidation activities in soybean oil when it was infused with the microalgae powder. Our results suggest that N. oculata could potentially be used as an additive in cooking oil to increase the shelf life and nutritional value of the oil and to reduce the production of free radicals from lipid oxidation when the oil is used at high-temperature cooking processes.

Plant ferredoxin-like protein (PFLP) outside chloroplast in Arabidopsis enhances disease resistance against bacterial pathogens.

Protection of crops against bacterial disease is an important issue in agricultural production. One of the strategies to lead plants become resistant against bacterial pathogens is employing a transgene, like plant ferredoxin-like protein (PFLP). PFLP is a photosynthetic type ferredoxin isolated from sweet pepper and contains a signal peptide for targeting towards chloroplasts. Our previous reports indicated that transgenic plants with this protein are more resistant against bacterial pathogens. However, this heterologous protein was visualized not only inside the chloroplasts, but also in the cytoplasm. In this article, we moved to study its heterologous expression in Arabidopsis by expressing the protein in chloroplast, apoplast and cytoplasm. This work was achieved by engineering a chloroplast target (CPF), an apoplast target (ESF), and cytoplasm target (DF) plants. The expression and subcellular localization of PFLP were analyzed by Western blot and immuno-staining by confocal microscopy, respectively. We tested the ability of the transgenic Arabidopsis for resistance to two Ralstonia solanacearum strains and their ability to increase the hypersensitive response (HR) triggered by harpin (HrpZ) from Pseudomonas syringae. The DF and ESF plants conferred resistance against bacterial wilt strains and increased HR by harpin, but no resistance found in the CPF plants. In addition, we determined the level of reduced ascorbate in all transgenic plants and further analyzed the expression of two NADPH-oxidase genes (AtrbohD and AtrbohF) in ESF plant. Among the transgenic Arabidopsis plants, ESF plants confer the highest resistance to bacterial pathogens and followed by DF plants. We concluded that PFLP enhances disease resistance in Arabidopsis when expressed in the apoplast or in cytoplasm but not when targeted into the chloroplast. This study provides a strategy for molecular breeding to improve resistance of crops against bacterial pathogens.

[Wheat transformation by electroporation with ring electrode].

Electroporation has been used effectively to deliver DNA into the tissue of intact wheat immature embryos. The physical parameters of electroporation were 770 V/cm field strength, 800 microF capacitor and 100 microg/mL of plasmid DNA, containing bar and GUS gene. The electroporation was carried out by a portable and permanent ring electrode that can be fitted into the wells of 24-well plates. The samples were pulsed three times. Integration of the introduced genes into the genome of transgenic wheat plants was shown by PCR and Southern blot analysis. Transformation frequency was 7.5%, that is higher than that of the 4.2% frequency by microprojectile bombardment.