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Mucin rare cores 5, 7, and 8 with 1,2-cis glycosidic bonds were prepared with exclusive stereo-selectivity from a versatile precursor. Enzyme-catalyzed regio-selective sialylation was then achieved, yielding natural sialylated rare cores.

Mg-doped HAP aerogel (MHAPA) was firstly in situ prepared via freeze-drying-calcination technology to capture U(VI). The U(VI) removal capacity by MHAPA even arrived 2685.6 mg g

A facile enzymatic modular assembly strategy for the preparative-scale synthesis of poly-N-acetyllactosamine (poly-LacNAc) glycans with varied lengths and designed sialylation and/or fucosylation patterns is described. These glycans were printed as a microarray to investigate their interactions with a panel of glycan binding proteins (GBPs). Binding affinities revealed that the avidity of GBPs could be largely affected by the length and the patterns of sialylation and fucosylation.

O-GalNAc glycans (or mucin O-glycans) play pivotal roles in diverse biological and pathological processes, including tumor growth and progression. Structurally defined O-GalNAc glycans are essential for functional studies but synthetic challenges and their inherent structural diversity and complexity have limited access to these compounds. Herein, we report an efficient and robust chemoenzymatic modular assembly (CEMA) strategy to construct structurally diverse O-GalNAc glycans. The key to this strategy is the convergent assembly of O-GalNAc cores 1–4 and 6 from three chemical building blocks, followed by enzymatic diversification of the cores by 13 well-tailored enzyme modules. A total of 83 O-GalNAc glycans presenting various natural glycan epitopes are obtained and used to generate a unique synthetic mucin O-glycan microarray. Binding specificities of glycan-binding proteins (GBPs) including plant lectins and selected anti-glycan antibodies towards these O-GalNAc glycans are revealed by this microarray, promoting their applicability in functional O-glycomics. Serum samples from colorectal cancer patients and healthy controls are assayed using the array reveal higher bindings towards less common cores 3, 4, and 6 than abundant cores 1 and 2, providing insights into O-GalNAc glycan structure-activity relationships., O-GalNAc glycans are essential in many biological and pathological processes, but difficult to access due to their structural complexity and synthetic challenges. Here, the authors report an efficient chemoenzymatic modular assembly strategy to construct structurally diverse O-GalNAc glycans, use the synthesised glycans to generate a synthetic mucin O-glycan microarray and profile binding specificities of glycan-binding proteins.

For decades, researchers have endeavored to develop a general automation system to synthesize oligosaccharides comparable to the preparation of oligonucleotides and oligopeptides by commercially available machines. Inspired by the success of automated oligosaccharide synthesis through chemical glycosylation, a fully machine-driven automated system is reported here for oligosaccharides synthesis through enzymatic glycosylation in aqueous solution. The designed full automation system is based on the use of a thermosensitive polymer and a commercially available peptide synthesizer. This study represents a proof-of-concept that the enzymatic synthesis of oligosaccharides can be achieved in an automated manner using a commercially available peptide synthesizer.

Controlled synthesis of metal-organic framework (MOF)-based materials with multiple levels of porous structures across different length scales is of great interest in various applications but it still remains challenging. Most of the current strategies are time consuming and labor intensive, and not readily scaled-up. In this work, we introduce a straightforward one-pot fabrication strategy to prepare a robust and flexible hierarchically macro-meso-micro porous HKUST-1/polyvinylidene fluoride (PVDF) composite through solvent evaporation, in which MOF crystallization and polymer precipitation are combined together. The effect of the MOF precursor and the polymer initial amount on the morphology of the final composite was thoroughly studied. The interaction between the MOF and the polymer during the evaporation process is the key factor, which would limit the mobility of the polymer chains and cause instability in the MOF growth, thus endowing the composite with a hierarchically macro-meso-micro porous structure. This "all-in-one" porous structure could enhance the mass transport property of molecules within the composite. The obtained HKUST-1/PVDF composite showed an enhanced CO2 adsorption rate constant of 0.821 min-1 (298 K, 1 bar), which was 3.5 times higher than that of the pristine MOF. In addition, the composite showed an equivalent gas adsorption capacity under all tested pressures and greatly improved water stability.

A promising strategy to treat wastewater containing heavy metal complexes (HMCs) is to employ oxidation processes before carrying out the conventional processes. Metal ion-catalyzed oxidation processes (MICOPs) have been confirmed to be suitable for the remediation of wastewater. However, the treatment of HMCs by MICOPs has seldom attracted researchers’ attention and the key mechanisms remain unclear. In this study, CuII-ethylenediamine tetraacetic acid (EDTA) was used to evaluate the decomplexation efficiency of various MICOPs, among which the CoII/peroxymonosulfate (PMS) system provided the best results. In-depth analysis of the decomplexation mechanism of CuII-EDTA indicated that the high affinity of Cu(II) to EDTA inhibits the exchange between CoII and CuII in CuII-EDTA, thus preventing the chelation of the catalytically active Co2+ with EDTA, which leads to the rapid decomplexation of CuII-EDTA. Moreover, through thermodynamic computation, MnII-EDTA, CdII-EDTA, and NiII-EDTA were selected as other HMC candidates to investigate their influence on the oxidation efficiency of the CoII/PMS system. The results confirmed that the oxidation efficiency of CoII/PMS is strongly dependent on the metal-ion replacement. Finally, we propose that the distinct performance of the Fenton(-like) process in decomplexing the NiII-EDTA and CuII-EDTA could be well explained by the metal-ion replacement mechanism.

O Mannosylation is a vital protein modification involved in brain and muscle development whereas the biological relevance of O-mannosyl glycans has remained largely unknown owing to the lack of structurally defined glycoforms. An efficient scaffold synthesis/enzymatic extension (SSEE) strategy was developed to prepare such structures by combining gram-scale convergent chemical syntheses of three scaffolds and strictly controlled sequential enzymatic extension catalyzed by glycosyltransferases. In total, 45 O-mannosyl glycans were obtained, covering the majority of identified mammalian structures. Subsequent glycan micro-array analysis revealed fine specificities of glycan-binding proteins and specific antisera.

Lacto-N-neotetraose and its sialyl and fucosyl derivatives including Lewis x (Le(x)) pentasaccharide, sialyl Lewis x (sLe(x)) hexasaccharide and internally sialylated derivatives were enzymatically synthesized from readily available lactoside, commercially available uridine 5'-diphosphate-glucose (UDP-Glc) and the corresponding monosaccharides using a highly efficient sequential one-pot multienzyme (OPME) strategy. The OPME strategy which combines bacterial glycosyltransferases and sugar nucleotide generation enzymes provides easy access to the biologically important complex oligosaccharides at preparative scale. Moreover, the same OPME strategy can be used for the regioselective introduction of sialic acid to the internal galactose unit of LNnT in a designed glycosylation route by simply changing the glycosylation sequence.

Dominant components of oxidized products of multi-walled carbon nanotubes were separated by column chromatography, the origin of highly visible fluorescence from carbon quantum dots was revealed, and the nature of weak near-UV-Vis fluorescence of oxidized carbon nanotubes from isolated sp2 carbon clusters was supported among the four proposed explanations through experimental and theoretical approaches. It was found that three dominant components including carbon quantum dots, short and long oxidized carbon nanotubes were produced during the oxidation of carbon nanotubes. The highly visible fluorescence was mainly originated from carbon quantum dots, while short and long oxidized carbon nanotubes only exhibited weak near-UV-Vis fluorescence. For the nature of fluorescence of oxidized carbon nanotubes, two proposed explanations including defects mechanism and an isolated carbon cluster mechanism were compared and discussed through theoretical analysis of corresponding model compounds. It was supported that the fluorescence is dominantly originated from sp2 carbon clusters isolated by sp3 carbons due to oxidation depending on the comparison between experimental data and calculated values. The results also indicated that carbon nanotubes can be transformed to large graphene oxide during oxidation. This work not only clearly demonstrated the origin of highly visible fluorescence in an oxidized carbon nanotube mixture and a reasonable explanation for fluorescence of oxidized carbon nanotubes, but also provided an example to understand visible fluorescent graphene oxide and carbon quantum dots.

A simple and efficient method to prepare halogenated carbon quantum dots (CQDs) through solvent-thermal reaction was reported. The halogenated CQDs were synthesized and further surface functionalization with diamines was achieved based on the halogenated CQDs as intermediates. The halogenated CQDs provide an alternative approach for surface modification of CQDs.

A simple and effective method to prepare highly efficient fluorescent multi-walled carbon nanotubes (MWCNTs) is reported. The quantum yield of the as-prepared MWCNTs is up to 0.25, and increases with the shortening of the aliphatic chain of the diamines functionalized on the tubes. The as-prepared MWCNTs have high selectivity for several transition metal ions based on fluorescence quenching which is due to the complexes of tubes and metal ions.

The facile synthesis of halogenated multi-walled carbon nanotubes with Cl, Br and I under high pressure and high temperature was reported, and the unique photoluminescence of the halogenated carbon nanotubes was investigated by means of experimental and theoretical approaches. The one-step and facile method to incorporate these halogens onto nanotubes’ surface involves high temperature and high pressure using a sealed vessel. This method is easily handled using SOCl2, Br2 and I2 as halogen sources and is accessible for the large-scale production of halogenated carbon nanotubes. The concentration of halogen in the samples by this method reaches up to 3–8% in weight. The UV-Vis photoluminescence of these halogenated carbon nanotubes was observed, and attributed to fluorescence, depending on their lifetimes. The fluorescence of the halogenated carbon nanotubes can be remarkably enhanced by the increase of introduced halogen atoms resulting from prolonging the reaction time. Different species of halogen atoms have little influence on the fluorescence emission behaviour, but affect their fluorescence lifetimes. The fluorescence is more likely to originate from sp2 carbon clusters isolated from sp3 carbons formed by the addition of halogen atoms, but a defect mechanism cannot be excluded from the present results. A series of compounds with different aromatic rings were modelled to predict the size of the isolated sp2 carbon clusters by comparing the calculated excitation and emission maximum wavelengths with their experimental data. Basing on these theoretical results, it is thought that the UV-Vis fluorescence of the halogenated carbon nanotubes may originate from the isolated sp2 carbon clusters containing 4–8 aromatic rings.

Different sizes of graphene oxide with tunable fluorescence colours were prepared by continuous chemical oxidation with multi-walled carbon nanotubes (MWCNTs) as precursor. The photoluminescence of as-prepared GO was attributed to fluorescence according to their luminescence lifetimes. The as-prepared GO exhibit colourful fluorescence, which can be tuned by the level of oxidation. It is found that the fluorescence emission can be bathochromically shifted with the increase of pH value, and the fluorescence can be strongly quenched by usual heavy metal ions except for Cd2+.

Nanosized N-doped graphene oxide (GO) with visible fluorescence in water was prepared by cutting and unzipping of N-doped carbon nanotubes (NCNTs) and used to distinguish between normal and transition metal ions. It is found that the fluorescence is bathochromically shifted as the level of oxidation is increased.

Identification of aluminium polyoxocations, MO(4)Al(12)(OH)(24)(H(2)O)(12)(7/8+) (M = Al, Ga and Ge) (K-MAl(12)) and Al(30)O(8)(OH)(56)(H(2)O)(26)(18+) (Al(30)), by their luminescence is reported. The fluorescence behavior of K-Al(13) has been found to differ with different metal ions and anions, implying a new discovery of a potential ion sensor.

A novel and simple method to prepare well dispersed single-walled carbon nanotubes with strong visible fluorescence in water is reported. The visible fluorescence was found to be responsive to pH value and metal ions, and tunable emission ability of oxidized SWCNTs depending on the excitation wavelength and a novel self-excitation and emission process were found.