N,N-Di-2-picolylamine (DPA)-derived diboronic acid receptors (NHBAs) with a flexible linker were designed and synthesized in this study, and two-component sensing ensembles based on cationic NHBAs and an anionic fluorescent indicator 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) were successfully developed for both monosaccharides and disaccharides sensing. The dibranched ortho-substituted receptor NHoBA exhibited unexpected selectivity towards lactose among five disaccharides used. The discrimination of five disaccharides and six monosaccharides was finally achieved by the integrated sensor array through linear discriminant analysis (LDA).

Four novel Zn²⁺ fluorescent sensors have been designed with N,N-bis(2-pyridylmethyl)ethylenediamine as chelator and 2-aminobenzamide as fluorophore. These sensors were prepared in two or three steps from readily available starting materials. Of the four designed sensors, ZnABA was found to be the most efficient Zn²⁺-specific fluorescent probe and has good solubility in biological buffer, a large Stokes shift (186 nm), a high off–on fluorescence response (16-fold enhancement), and distinct selectivity towards Zn²⁺ over other metal ions. Our results have demonstrated an excellent linear relationship between the fluorescence intensity of ZnABA and the Zn²⁺ concentration from 0 to 10 μM, which indicates that ZnABA has the potential to be used for the quantitative determination of Zn²⁺ in an aqueous environment.

The use of nanobiocatalysts, with the combination of nanotechnology and biotechnology, is considered as an exciting and rapidly emerging area. The use of iron oxide magnetic nanoparticles, as enzyme immobilization carriers, has drawn great attention because of their unique properties, such as controllable particle size, large surface area, modifiable surface, and easy recovery. In this study, various γ-Fe₂O₃/Fe₃O₄ magnetic nanoparticles with immobilized proteases were successfully prepared by three different immobilization strategies including A) direct binding, B) with thiophene as a linker, and C) with triazole as a linker. The oligopeptides syntheses catalyzed by these magnetic nanoparticles (MNPs) with immobilized proteases were systematically studied. Our results show that i) for magnetic nanoparticles immobilized α-chymotrypsin, both immobilization strategies A and B furnished good reusability for the Z-Tyr-Gly-Gly-OEt synthesis, the MNPs enzymes can be readily used at least five times without significant loss of its catalytic performance: ii) In the case of Z-Asp-Phe-OMe synthesis catalyzed by magnetic nanoparticles immobilized thermolysin, immobilization Strategy B provided the best recyclability: iii) For the immobilized papain, although Strategy A or B afforded an immobilized enzyme for the first cycle of Z-Ala-Leu-NHNHPh synthesis in good yield, their subsequent catalytic activity decreased rapidly. In general, the γ-Fe₂O₃ MNPs were better for use as an immobilization matrix, rather than the Fe₃O₄ MNPs, owing to their smaller particle size and higher surface area.

Ganglioside GM₃ [α-Neu5Ac-(2,3)-β-Gal-(1,4)-β-Glc-(1,1)-Cer; 1] is considered as an important tumor-associated carbohydrate antigen, which can be used in the development of tumor vaccine. In this study, a facile and convergent synthetic strategy for GM₃ was developed, and the preparation of three building blocks started from the most readily available compounds sialic acid, lactose, and L-serine. Ceramide aglycon 9 was constructed from L-serine in 13 steps with 6 % overall yield, and lactosyl trichloroacetimidate 14 was synthesized from lactose in 7 steps with 25 % yield. With novel N-acetyl-5-N,4-O-oxazolidinone protected p-toluenethiosialoside 15 as donor, which was developed by our group, the sialylation of benzoyl-protected lactosyl ceramide diol 23 was successfully accomplished in 54 % yield. Our strategy here provides a shorter linear total synthesis of GM₃ in five steps and with 26 % overall yield. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)