Photodegradation of organic pollutants in aqueous solution is a promising method for environmental purification. Photocatalysts capable of promoting this reaction are often composed of noble metal nanoparticles deposited on a semiconductor. Unfortunately, the separation of these semiconductor-metal nanopowders from the treated water is very difficult and energy consumptive, so their usefulness in practical applications is limited. Here, a precisely controlled synthesis of a large-scale and highly efficient photocatalyst composed of monolayered Au nanoparticles (AuNPs) chemically bound to vertically aligned ZnO nanorod arrays (ZNA) through a bifunctional surface molecular linker is demonstrated. Thioctic acid with sufficient steric stabilization is used as a molecular linker. High density unaggregated AuNPs bonding on entire surfaces of ZNA are successfully prepared on a conductive film/substrate, allowing easy recovery and reuse of the photocatalysts. Surprisingly, the ZNA-AuNPs heterostructures exhibit a photodegradation rate 8.1 times higher than that recorded for the bare ZNA under UV irradiation. High density AuNPs, dispersed perfectly on the ZNA surfaces, significantly improve the separation of the photogenerated electron-hole pairs, enlarge the reaction space, and consequently enhance the photocatalytic property for degradation of chemical pollutants. Photoelectron, photoluminescence and photoconductive measurements confirm the discussion on the charge carrier separation and photocatalytic experimental data. The demonstrated higher photodegradation rates demonstrated indicate that the ZNA-AuNPs heterostructures are candidates for the next-generation photocatalysts, replacing the conventional slurry photocatalysts.

Antibody microarrays have important applications for the sensitive detection of biologically important target molecules and as biosensors for clinical applications. Microarrays produced by oriented immobilization of antibodies generally have higher antigen-binding capacities than those in which antibodies are immobilized with random orientations. Here, we present a UV photo-cross-linking approach that utilizes boronic acid to achieve oriented immobilization of an antibody on a surface while retaining the antigen-binding activity of the immobilized antibody. A photoactive boronic acid probe was designed and synthesized in which boronic acid provided good affinity and specificity for the recognition of glycan chains on the Fc region of the antibody, enabling covalent tethering to the antibody upon exposure to UV light. Once irradiated with optimal UV exposure (16 mW/cm(2)), significant antibody immobilization on a boronic acid-presenting surface with maximal antigen detection sensitivity in a single step was achieved, thus obviating the necessity of prior antibody modifications. The developed approach is highly modular, as demonstrated by its implementation in sensitive sandwich immunoassays for the protein analytes Ricinus communis agglutinin 120, human prostate-specific antigen, and interleukin-6 with limits of detection of 7.4, 29, and 16 pM, respectively. Furthermore, the present system enabled the detection of multiple analytes in samples without any noticeable cross-reactivities. Antibody coupling via the use of boronic acid and UV light represents a practical, oriented immobilization method with significant implications for the construction of a large array of immunosensors for diagnostic applications.

Herein, we report the first characterization of a novel galactokinase from Meiothermus taiwanensis sp. nov. WR-220 (MtGalK), which is overexpressed in E. coli and exhibits a k cat /K m value of 168.47 mM À1 s À1 toward Gal at 75 8C. The thermophilic MtGalK shows specific substrate recognition toward the Gal configuration with limited tolerance for modifications at the C-2 position to form products such as GalN-1-P, GalN 3 -1-P, and GalNAc-1-P. Due to its unique thermostability toward elevated reaction temperatures, MtGalK served as an ideal biocatalyst in the synthesis of useful sugar-1-phosphates and was further combined with glucose-1-phosphate thymidylyltransferase (RmlA) and a-1,4-galactosyltransferase (LgtC) to achieve the efficient preparative-scale synthesis of globotriose analogs (Gb3) using a one-pot three-enzyme system. In combination with a chemical synthetic strategy, a carbohydrate antigen from breast cancer stem cells, stage specific embryonic antigen-3 (SSEA-3) pentasaccharide, was synthesized from Gb3 in ten steps with a 23% overall yield. This flexible chemoenzymatic strategy for the synthesis of SSEA-3 also allowed us to further expand the inventory of valuable natural and non-natural glycans.

An efficient stereoselective synthesis of alpha-(2-->9)-tetrasialic acid was achieved using tri-O-chloroacetyl-derivatized sialyl donor and a triol sialyl acceptor. Both the acceptor and the donor were also protected with a cyclic 5-N-4-O-carbonyl protecting group. The donor is highly reactive and enabled alpha-selective sialylation with various primary, secondary, and tertiary acceptors under in situ activation conditions (NIS/TfOH, -78 degrees C, acetonitrile/dichloromethane). The trans-fused oxazolidinone ring and O-chloroacetyl protecting groups were easily removed under mild reaction conditions to provide the fully deprotected alpha(2-->9)-tetrasialic acid.

Efficient structural characterization is important for quality control when developing novel materials. In this study, we demonstrated the soft ionization capability of the hybrid of immobilized silica and 2,5-dihydrobenzoic acid (DHB) on iron oxide magnetic nanoparticles in MALDI-TOF MS with a clean background. The ratio between SiO(2) and DHB was examined and was found to affect the surface immobilization of DHB on the nanoparticle, critically controlling the ionization efficiency and interference background. Compared with commercial DHB, the functionalized nanoparticle-assisted MALDI-TOF MS provided superior soft ionization with production of strong molecular ions within 5 ppm mass accuracy on a variety of new types of synthetic materials used for solar cells, light emitting devices, dendrimers, and glycolipids, including analytes with either thermally labile structures or poor protonation tendencies. In addition, the enhancements of the molecular ion signal also provided high-quality product-ion spectra allowing structural characterization and unambiguous small molecule identification. Using this technique, the structural differences among the isomers were distinguished through their characteristic fragment ions and comprehensive fragmentation patterns. With the advantages of long-term stability and simple sample preparation by deposition on a regular sample plate, the use of DHB-functionalized nanoparticles combined with high-resolution MALDI-TOF MS provides a generic platform for rapid and unambiguous structure determination of small molecules.