Bacteria-Assisted Synthesis of Nanosheet-Assembled TiO Hierarchical Architectures for Constructing TiO-Based Composites for Photocatalytic and Electrocatalytic Applications.

Synthesis and application of three-dimensional TiO hierarchical architectures are one of the major priorities in the research and development of TiO catalysts. Using bacteria as a template and a reactor, a bioinspired strategy was developed in the present study to synthesize nanosheet-assembled TiO hierarchical architectures (N-TiO-HA) and relative composites for photocatalytic and electrocatalytic applications. In the first part of this work, three kinds of bacteria were used for the synthesis of N-TiO-HA with satisfactory monodispersity, and the growth mechanism was investigated.

Bacteria assisted protein imprinting in sol-gel derived films.

A hierarchical imprinting strategy was used to create protein imprints in a silicate film with a high binding capacity as well as selectivity toward the imprint protein and little specificity towards other proteins. In the first part of this work, rod-shaped bacteria were used as templates to create imprints in silica films of various thicknesses to open up the silica framework and increase the surface area exposed to solution. In the second part, the protein (e.

Bio-inspired chemical reactors for growing aligned gold nanoparticle-like wires.

Bioinspired masks, created by merging sol-gel chemistry with biotemplating, were used as local chemical reactors to grow aligned arrays of gold nanoparticle-like wires.

Self-supporting nanopore membranes with controlled pore size and shape.

Self-supporting membranes containing either isolated or organized arrays of nanosized pores have been prepared using a nonlithographic approach by coupling sol-gel processing, thin film preparation, and templating. Specifically, polystyrene latex spheres were doped into a hybrid sol prepared from tetraethoxysilane and dimethyldiethoxysilane and the resultant sol spin cast on a sacrificial support. Upon removal of the template and the sacrificial support, the self-supporting nanopore membranes were transferred to glass for characterization by atomic force microscopy and scanning electron microscopy.

Visualized investigation of yeast transformation induced with Li+ and polyethylene glycol.

The effects of Li(+) and polyethylene glycol (PEG) on the genetic transformation of Saccharomyces cerevisiae were investigated by using fluorescence microscopy (FM) to visualize the binding of plasmid DNA labeled with YOYO-1 to the surface of yeast cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM) to image the change in surface topography of yeast cells, coupled with transformation frequency experiments. The results showed that under the same conditions, the transformation frequencies of yeast protoplasts were much higher than those of intact yeast cells. PEG was absolutely required for the binding of DNA to the surface of intact yeast cells or yeast protoplasts, and had no effect on the surface topography of intact yeast cells or yeast protoplasts.

Heat-fixation method used in an atomic force microscopy study of cell morphology.

In order to overcome the difficulties with existing methods for sample immobilization in imaging Halobacterium salinarum (H. salinarum) living in a highly salty medium by atomic force microscopy (AFM), a heat-fixation method was, for the first time, used to overcome existing problems in preparing samples for AFM. The effect on the cell morphology of the heat-fixation method was studied by MAC mode AFM, and was compared with the drop-and-dry and the polylysine-adhesion methods.

Core/shell quantum-dot-photosensitized nano-TiO2 films: fabrication and application to the damage of cells and DNA.

Through the use of monodisperse core/shell quantum dots (QDs) as photosensitizers for the first time, a novel strategy for the fabrication of QD-photosensitized nano-TiO2 films was demonstrated. Core/shell QDs were self-assembled on nano-TiO2 films through carboxyls as anchoring groups to metal oxides. Atomic force microscopy and some other experiments showed the fabrication strategy is successful.

Quantum-dot-labeled DNA probes for fluorescence in situ hybridization (FISH) in the microorganism Escherichia coli.

Semiconductor quantum dots (QDs) as a kind of nonisotopic biological labeling material have many unique fluorescent properties relative to conventional organic dyes and fluorescent proteins, such as composition- and size-dependent absorption and emission, a broad absorption spectrum, photostability, and single-dot sensitivity. These properties make them a promising stable and sensitive label, which can be used for long-term fluorescent tracking and subcellular location of genes and proteins. Here, a simple approach for the construction of QD-labeled DNA probes was developed by attaching thiol-ssDNA to QDs via a metal-thiol bond.

Direct electrochemistry and electrocatalysis of heme proteins entrapped in agarose hydrogel films in room-temperature ionic liquids.

The electrochemistry and electrocatalysis of a number of heme proteins entrapped in agarose hydrogel films in the room-temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]) have been investigated. UV-vis and FTIR spectroscopy show that the heme proteins retain their native structure in agarose film. The uniform distribution of hemoglobin in agarose-dimethylformamide film was demonstrated by atomic force microscopy.

Preparation and characterization of overcoated II-VI quantum dots.

A convenient route for the synthesis of high-quality overcoated II-VI quantum dots (QDs) is reported in this paper. Simple salts, such as Cd(Ac)2 and Zn(Ac)2 were used to replace organometallics, whose disadvantage is obvious. Size-tunable core/shell structured QDs (CdSe/ZnS, CdSe/CdS, etc.

Yeast transformation process studied by fluorescence labeling technique.

A new method based on fluorescence imaging and flow cytometry was developed to investigate the transformation process of Saccharomyces cerevisiae AY. Yeast and fluorescent-labeled plasmid pUC18 were used as models of cells and DNA molecules, respectively. Binding of DNA molecules to yeast cell surfaces was observed.

Combing DNA on CTAB-coated surfaces.

A fluorescence microscope (FM) coupled with an intensified charge-coupled device (ICCD) camera was used to investigate the combing of DNA on cetyltrimethyl ammonium bromide (CTAB)-coated glass surfaces. DNA molecules can be combed uniform and straight on CTAB-coated surfaces. Different combing characteristics at different pH values were found.

Direct electrochemistry and electrocatalysis of heme-proteins entrapped in agarose hydrogel films.

Three heme-proteins, including myoglobin (Mb), hemoglobin (Hb) and horseradish peroxidase (HRP), were immobilized on edge-plane pyrolytic graphite (EPG) electrodes by agarose hydrogel. The proteins entrapped in the agarose film undergo fast direct electron transfer reactions, corresponding to FeIII = e- --> FeII. The formal potential (E degrees'), the apparent coverage (Gamma), the electron transfer coefficient (alpha) and the apparent electron transfer rate constant (ks) were calculated by integrating cyclic voltammograms or performing nonlinear regression analysis of square wave voltammetric (SWV) experimental data.