Bi(â ¢) and Ce(â £) functionalized carbon nitride photocatalyst for antibiotic degradation: Synthesis, toxicity, and mechanism investigations.

Graphite-phase carbon nitride (g-C3N4) has shown great potential for antibiotic wastewater treatment due to its unique electronic structure and corresponding to visible light. In this study, a series of Bi/Ce/g-C3N4 photocatalysts with different doping amount were developed by direct calcination method for Rhodamine B and sulfamethoxazole photocatalytic degradation. The experiment result shows that the photocatalytic performance of Bi/Ce/g-C3N4 catalysts were better than that of single component samples. Under the optimal experimental conditions, the degradation rates of RhB (20 min) and SMX (120 min) by 3Bi/Ce/g-C3N4 reached 98.3% and 70.5%, respectively. The theoretical calculation results of DFT show that after Bi and Ce doping modification, the band-gap width of g-C3N4 is reduced to 1.215 eV and carrier migration rate is greatly improved. The enhanced photocatalytic activity was mainly attributed to the capture of electrons after doping modification, which inhibition of photogenerated carriers recombination and reduced the gap width. The cyclic treatment experiment of sulfamethoxazole showed that Bi/Ce/g-C3N4 catalysts had good stability. Ecosar evaluation and leaching toxicity test showed that Bi/Ce/g-C3N4 can be safely used for wastewater treatment. This study provides a perfect strategy for modifying g-C3N4 and a new way to improve the photocatalytic performance.

Teosinte confers specific alleles and yield potential to maize improvement.

KEY MESSAGE: Teosinte improves maize grain yield and broadens the maize germplasm. Seventy-one quantitative trait loci associated with 24 differential traits between maize and teosinte were identified. Maize is a major cereal crop with a narrow germplasm that has limited its production and breeding progress. Teosinte, an ancestor of maize, provides valuable genetic resources for maize breeding. To identify the favorable alien alleles in teosinte and its yield potential for maize breeding, 4 backcrossed maize-teosinte recombinant inbred line (RIL) populations were cultivated under five conditions. A North Carolina mating design II experiment was conducted on inbred lines with B73 and Mo17 pedigree backgrounds to analyze their combining ability. Abundant phenotypic variation on 26 traits of four RIL populations were found, of which barren tip length, kernel height, and test weight showed positive genetic improvement potential. The hybrid FM132 (BD138/MP116) showed a superior grain yield to that of the check, with an average yield gain of 4.86%. Moreover, inbred lines BD138 and MP048 showed a higher general grain yield combining ability than those of their corresponding checks. We screened 4,964,439 high-quality single-nucleotide polymorphisms in the BD (B73/Zea diploperennis) RIL population for bin construction and used 2322 bin markers for genetic map construction and quantitative trait loci (QTL) mapping. Via inclusive composite interval mapping, 71 QTL associated with 24 differential traits were identified. Gene annotation and transcriptional expression suggested that Zm00001eb352570 and Zm00001eb352580, both annotated as ethylene-responsive transcription factors, were key candidate genes that regulate ear height and the ratio of ear to plant height. Our results indicate that teosinte could broaden the narrow maize germplasm, improve yield potential, and provide desirable alleles for maize breeding.

Liposomes encapsulating artificial cytosol as drug delivery system.

The fabrication of cell models containing artificial cytosol is challenging. Herein we constructed an artificial cytosol contained cell model by electroformation method. Agarose was selected as the main component of the artificial cytosol, and sucrose was added into the agarose to regulate the sol viscosity and the phase transition temperature. The viscosity of the sol with the mass ratio (agarose-sucrose) 1:9 was closest to the natural cytosol. DSPC/20 mol% cholesterol was used to form large unilamellar vesicles (LUVs) as cell model compartment. The rhodamine release experiment confirmed that the unique release profile of agarose-sucrose@LUVs is suitable as a drug carrier. Doxorubicin is loaded in the agarose-sucrose@LUVs, and their half maximum inhibition concentration on HeLa cells is 0.016 µmol L-1, which means 28.7 times increase in inhibition efficiency over free doxorubicin.

Giant Unilamellar Vesicle Microarrays for Cell Function Study.

Giant unilamellar vesicles (GUVs) are widely used as artificial cell models which contribute to elucidate fundamental questions on origin of life and cell functions. Herein, the GUV microarrays were developed using a point-to-plane electrode system combined with microcontact stripping technique. The biomolecules (DNA, etc.) were selectively encapsulated only inside patterned GUVs. The GUV arrays were used to investigate species mass transport across cell membranes. The release of carboxyfluorescein from GUVs showed a melittin concentration dependent manner. The diffusion coefficient were 0.37 × 10-11, 0.36 × 10-11, 0.54 × 10-11, 1.10 × 10-11, 1.74 × 10-11, 2.31 × 10-11, and 3.62 × 10-11 m2/s for 0, 0.5, 1.0, 2.0, 3.0, 4.0, and 5.0 µM melittin, respectively. The GUV arrays were also a good platform for cell metabolism investigation. Horseradish peroxidase (HRP) loaded GUV microarrays were used to mimic internal metabolism by exposing them to the substrates of H2O2 and o-PD to yield fluorescent 2,3-diaminophenazine (2,3-DAP).The proposed GUV arrays have great potential in cell function studies.

Multicompartmentalized Microreactors Containing Nuclei and Catalase-Loaded Liposomes.

Multicompartmentalized microreactors are considered as cell mimics with hierarchical structures inspired by mammalian cells. We report the successful assembly and encapsulation of purified nuclei from RAW 264.7 cells (pNuc) into alginate-based microreactors. We demonstrate the preserved function of nuclei within the microreactors for mRNA production. Further, we load catalase-loaded liposomes (Lcat) into the microreactors to break down hydrogen peroxide (H2O2) into oxygen and water. Assemblies containing both natural pNuc and synthetic Lcat show significantly higher mRNA production in the presence of H2O2 compared to microreactors without Lcat or no H2O2 present, suggesting a beneficial effect of the locally enzymatically produced oxygen for transcription. This novel type of microreactors, containing both natural and synthetic compartments, presents a substantial advancement from assemblies equipped with solely synthetic units and offers opportunities as hypoxia models or for cell-free protein synthesis.

Interaction of cells with patterned reactors.

Surface coatings that allow externally controlled interaction with cells are of interested for diverse biomedical applications. We fabricated particle patterns and assessed the interaction of these substrates with endothelial cells and hepatocytes. The particles were turned into subcompartmentalized reactors by immobilizing glucose oxidase loaded liposomes sandwiched between polymer layers. The reactor activities depending on the number of liposome deposition steps were confirmed in solution and on patterned surfaces. Finally, reduced viability of hepatocytes adhering to the reactor patterned surfaces in the presence of glucose was observed due to the local production of hydrogen peroxide. This first report on patterned reactors in combination with cells opens up vast opportunities to assemble interactive nanobiointerfaces.

Fabrication of Thickness-Controllable Micropatterned Polyelectrolyte-Film/Nanoparticle Surfaces by Using the Plasma Oxidation Method.

We have demonstrated a novel way to form thickness-controllable polyelectrolyte-film/nanoparticle patterns by using a plasma etching technique to form, first, a patterned self-assembled monolayer surface, followed by layer-by-layer assembly of polyelectrolyte-films/nanoparticles. Octadecyltrimethoxysilane (ODS) and (3-aminopropyl)triethoxysilane (APTES) self-assembled monolayers (SAMs) were used for polyelectrolyte-film and nanoparticle patterning, respectively. The resolution of the proposed patterning method can easily reach approximately 2.5 µm. The height of the groove structure was tunable from approximately 2.5 to 150 nm. The suspended lipid membrane across the grooves was fabricated by incubating the patterned polyelectrolyte groove arrays in solutions of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) giant unilamellar vesicles (GUVs). The method demonstrated here reveals a new path to create patterned 2D or 3D structures.

Point-to-Plane Nonhomogeneous Electric-Field-Induced Simultaneous Formation of Giant Unilamellar Vesicles (GUVs) and Lipid Tubes.

It is well-known that homogeneous electric fields can be used to generate giant unilamellar vesicles (GUVs). Herein we report an interesting phenomenon of formation of GUVs and lipid tubes simultaneously using a nonhomogeneous electric field generated by point-to-plane electrodes. The underlying mechanism was analyzed using finite element analysis. The two forces play main roles, that is, the pulling force (F) to drag GUVs into lipid tubes induced by fluid flow, and the critical force (Fc) to prevent GUVs from deforming into lipid tubes induced by electric fields. In the center area underneath the needle electrode, the GUVs were found because F is less than Fc in that region, whereas in the edge area the lipid tubes were obtained because F is larger than Fc. The diffusion coefficient of lipid in the tubes was found to be 4.45 µm(2) s(-1) using a fluorescence recovery after photobleaching (FRAP) technique. The method demonstrated here is superior to conventional GUV or lipid tube fabrication methods, and has great potential in cell mimic or hollow material fabrication using GUVs and tubes as templates.