硅胶及其衍生物作为基体的激光解吸离子化飞行时间质谱

制备了一种新型无机基体材料(硅胶及其衍生物)用于测定激光解吸离子化飞行时间质谱,建立了一种新的质谱分析方法,并用以解决传统MALDI-TOFMS存在的基体干扰问题.该法适合于低分子量化合物的分析.同时探讨了该新解吸离子化方法的机理.     

亲水金和憎水二氧化硅纳米颗粒对葡萄糖生物传感器响应灵敏度的增强作用

用亲水金、憎水二氧化硅纳米颗粒固定葡萄糖氧化酶(GOD),采用聚乙烯醇缩丁醛(PVB)为辅助固酶膜基质来制备葡萄糖生物传感器,并考察了亲水金、憎水二氧化硅纳米颗粒对酶电极电流响应的影响.实验表明,引入纳米粒子可显著增强电极响应灵敏度.并对两种不同性质纳米颗粒所起作用的可能机理进行讨论,从理论和实验上证明了纳米颗粒对固定酶的作用.为制备有实用价值的葡萄糖生物传感器提供了可供参考的实验和理论依据.     

STUDY ON THE IMMOBILIZATION OF PAPAIN WITH A MACROPOROUS BEAD CARRIER OF COPOLYMER CONTAINING MONOMER UNITS OF NAMINOETHYL ACRYLAMIDE AND VINYL ALCOHOL*

 A kind of macroporous bead carrier of copolymer containing monomer units of N-aminoethyl acrylamide and vinylalcohol was synthesized, i.e. the MR-AA carrier. Papain was immobilized on the carrier using glutaraldehyde as the couplingagent. The enzymatic activity of the immobilized papain was compared with free papain using casein as a substrate, and theeffects of glutaraldehyde concentration, pH, temperature, time and papain amount added on the activity recovery were alsoinvestigated. The results show that the MR-AA carrier contains reactive primary amine groups,hydrophilic amido links and hydroxyl groups,as well as macroporous structures based on its matrix (MR-AV matrix),furthermore,the activity recovery of papain in the immobilization could reach 48%～58%.In comparison with free papain,the resulting immobilized papain exhibits a remarkable thermostability and better reusability.     

Protein interactions in covalently attached dextran layers

Protein interactions with polymeric carbohydrates play an important role for application in chromatography, biomaterials and biophysics. In this study, we present a detailed morphological and functional characterization of covalently side-bound dextran layers by spectroscopic ellipsometry (SE) and reflectometric interference spectroscopy (RIfS). The surface chemistry was monitored step-by-step by ellipsometric characterization of the surface loading. Dextrans of various molecular masses (10–2000 kD) were immobilized leading to surface loadings between 3 and 8 ng mm⁻². The refractive indices of the covalently attached dextran layers under atmospheric conditions (n_D=1.51) were very close to the refractive index of a spin-coated dextran layer (n_D=1.52) indicating dense and homogeneous coverage achieved by the coupling chemistry. Under buffer solution, refractive indices between 1.34 and 1.365 and thicknesses between 20 and 40 nm of these dextran layers were determined. A dextran concentration in the hydrated layers of 0.05–0.21 g cm⁻³ was estimated from the refractive index. The density and the thickness of the hydrated layers increased with molecular mass of the dextran. Non-specific binding was strongly reduced by the dextran layers and decreased with increasing thickness and density of the layer. Specific antibody binding to haptens immobilized in the dextran layer lead to an increase of both the density and the thickness of the layers. Time resolved detection by RIfS indicated significant decrease of protein mobility in the dextran layer. From these results we conclude that the functional properties of dextran layers with respect to protein interactions are determined by their effective pore-size, which is controlled by the number of bonds, the surface loading and the concentration of charged groups in the polymer.     

压电免疫传感器用于B因子的测定

B因子是一种不耐热的球蛋白,它参与机体的防御,在炎症过程、细胞和组织损伤中均起重要作用.B因子的检测方法常用的有单扩散法、火箭电泳法和溶血法,前者灵敏度不高,重复性差;后两者操作较复杂^[1,2].     

N,N-Diethanolaminomethyl Polystyrene: An Efficient Solid Support to Immobilize Boronic Acids

The key to the efficiency of N,N-diethanolaminomethyl polystyrene (DEAM-PS), the first solid support capable of coupling to boronic acids, is the formation of a stable, resin-bound boronic ester ate adduct (see scheme). With this resin it is now possible to efficiently immobilize a wide variety of boronic acids including functionalized ones that can be derivatized by solid-phase combinatorial synthesis.     

Dynamic Hydrogen-Bonded Zinc Adeninate Framework (ZAF) for Immobilization of Catalytic DNA

Effective immobilization and delivery of genetic materials is at the forefront of biological and medical research directed toward tackling scientific challenges such as gene therapy and cancer treatment. Herein we present a biologically inspired hydrogen-bonded zinc adeninate framework (ZAF) consisting of zinc adeninate macrocycles that self-assemble into a 3D framework through adenine-adenine interactions. ZAF can efficiently immobilize DNAzyme with full protection against enzyme degradation and physiological conditions until it is successfully delivered into the nucleus. As compared to zeolitic imidazolate frameworks (ZIFs), ZAFs are twofold more biocompatible with a significant loading efficiency of 96 %. Overall, our design paves the way for expanding functional hydrogen-bonding-based systems as potential platforms for the loading and delivery of biologics.     

A Dynamic Defect Generation Strategy for Efficient Enzyme Immobilization in Robust Metal-Organic Frameworks for Catalytic Hydrolysis and Chiral Resolution

Enzyme immobilization has been demonstrated to be a favorable protocol for promoting the industrialization of bioactive molecules, but still with formidable challenge. Addressing this challenge, we create a dynamic defect generation strategy for enzyme immobilization by using the dissociation equilibrium of metal-organic frameworks (MOFs) mediated by enzymes. Enzymes can act as “macro ligands” to generate competitive coordination against original ligands, along with the release of metal clusters of MOFs to generate defects, hence promoting the gradual transport of enzymes from the surface to inside. Various enzymes can be efficiently immobilized in MOFs to afford composites with good enzymatic activities, protective performances and exceptional reusabilities. Moreover, multienzyme bioreactors capable of efficient cascade reactions can also be generated. This study provides new opportunities to construct highly efficient biocatalysts incorporating different types of enzymes.     

A Supported Catalyst that Enables the Synthesis of Colorless CO2-Polyols with Ultra-Low Molecular Weight

Ultra-low molecular weight (ULMW) CO₂-polyols with well-defined hydroxyl end groups represent useful soft segments for the preparation of high-performance polyurethane foams. However, owing to the poor proton tolerance of catalysts towards CO₂/epoxide telomerization, it remains challenging to synthesize ULMW yet colorless CO₂-polyols. Herein, we propose an immobilization strategy of constructing supported catalysts by chemical anchoring of aluminum porphyrin on Merrifield resin. The resulting supported catalyst displays both extremely high proton tolerance (≈8000 times the equivalents of metal centers) and independence of cocatalyst, affording CO₂-polyols with ULMW (580 g mol⁻¹) and high polymer selectivity (>99 %). Moreover, the ULMW CO₂-polyols with various architectures (tri-, quadra-, and hexa-arm) can be obtained, suggesting the wide proton universality of supported catalysts. Notably, benefiting from the heterogeneous nature of the supported catalyst, colorless products can be facilely achieved by simple filtration. The present strategy provides a platform for the synthesis of colorless ULMW polyols derived from not only CO₂/epoxides, but also lactone, anhydrides etc. or their combinations.     

Single-Atom Catalysts on Covalent Triazine Frameworks: at the Crossroad between Homogeneous and Heterogeneous Catalysis

Heterogeneous single-site and single-atom catalysts potentially enable combining the high catalytic activity and selectivity of molecular catalysts with the easy continuous operation and recycling of solid catalysts. In recent years, covalent triazine frameworks (CTFs) found increasing attention as support materials for particulate and isolated metal species. Bearing a high fraction of nitrogen sites, they allow coordinating molecular metal species and stabilizing particulate metal species, respectively. Dependent on synthesis method and pretreatment of CTFs, materials resembling well-defined highly crosslinked polymers or materials comparable to structurally ill-defined nitrogen-containing carbons result. Accordingly, CTFs serve as model systems elucidating the interaction of single-site, single-atom and particulate metal species with such supports. Factors influencing the transition between molecular and particulate systems are discussed to allow deriving tailored catalyst systems.