Using the Aggregation of Latex Polymers in the Fabrication of Reproducible Enzyme Electrodes

An enzyme electrode for glucose is described as a model system to demonstrate a fabrication method using latex aggregation and entrapment of enzyme. Electrosterically‐stabilized latex particles synthesized by emulsion polymerization in batch from acrylic acid, methyl methacrylate and butyl acrylate, and glucose oxidase were coagulated together at pH 5.5 with ethanol. A platinum disk electrode dipped in the solution becomes coated with latex/enzyme. The relative thickness of the film and relative amount of enzyme may be controlled by the time the electrode is in contact with the solution. The enzyme was then immobilized by covalent attachment of amine groups to carboxylic moieties in the polymer using 1‐ethyl‐3(3‐dimethylaminopropyl)‐carbodiimide hydrochloride and N‐hydroxysuccinimide. Five minutes contact with the latex/enzyme solution and subsequent amide coupling, gave electrodes with a reproducibility of 5.7% RSD, a wide dynamic range (0–100 mM) and good storage properties.     

聚马来松香乙二醇酯Cu(II)配合物固定化漆树漆酶的研究

制备了聚马来松香乙二醇酯(MEEP)Cu2 、Ni2 、Ca2 和Mg2 金属离子配合物,并分别以4种配合物为载体固定化漆树漆酶,初步探讨了反应时间对酶固定化的影响,考察了固定化酶的性质。实验结果表明,在反应温度为25℃条件下,漆树漆酶的最佳固定化时间为16h;MEEPCu2 配合物固定化酶的固定化结果较好,重复使用6次后,酶相对保留活力为55.0%;该固定化酶的最适作用温度为40℃,pH值范围为5.89~9.23,固定化漆树漆酶具有比游离酶更好的热稳定性和更广泛的pH值适用范围。     

Preparation and characterization of polyethylene based graft copolymers. Applications in the immobilization of enzymes

In the last few years new copolymeric supports for the immobilization of biological compounds have been developed. The graft copolymer polyethylene-g.co-hydroxyethyl methacrylate, partially hydrolyzed, has shown to be a very promising support for this purpose.

The more recent work in the preparation and characterization of this copolymer, as well as the immobilization of a lipase, is reported in this paper. Branches of poly(hydroxyethyl methacrylate) were grafted onto low density polyethylene by using gamma radiation. The influence of the presence and absence of air, as well as the monomer concentration on the yield of grafting were evaluated.

The obtained copolymers were characterized by DSC and FTIR. The influence of the support properties on the synthesis biocatalytic activity was detected.     

Preparation of glass capillary columns coated with immobilized OV-240-OH (33% cyanopropyl substituted,OH-terminated). An approach to improve the inertness and thermal stability of cyanoalkyl polysiloxane coatings

Coating intensely leached glass capillaries with OV-240-OH, the most polar commercially available OH-terminated polysiloxane phase at the present time, is described. Beside chemical bonding of the phase via condensation with silanol groups of the support, additional immobilization using dimethyltetramethoxysiloxane as a crosslinker is carried out. After in situ methylation of the immobilized coating, and transformation of acidic impurities of the cyanopropyl substituted phase into the respective methyl esters, increased inertness of the column was observed. Working instructions are given, and processes involved are discussed.     

Synthesis, structure, immobilization and solid-state NMR of new dppp- and tripod-type chelate linkers

Chelating phosphines incorporating ethoxysilane functions for immobilizations have been synthesized and fully characterized. (EtO)Si(CH₂PPh₂)₃, (EtO)₂Si(CH₂PPh₂)₂, and Si(CH₂PPh₂)₄ could be prepared in high yields from cheap starting materials. The ethoxysilanes, as well as a Pd complex thereof have been characterized by X-ray structures, and immobilized on silica. The success of the immobilization was proved by ³¹P solid-state NMR of the dry materials and of the suspensions. Two representative chelate metal complexes, (EtO)₂Si(CH₂PPh₂)₂PdCl₂ and (EtO)Si(CH₂PPh₂)₃W(CO)₃ have been synthesized, characterized and immobilized.     

辐射聚合固定化α—淀粉酶的研究

用低温辐射聚合法将α-淀粉酶固定到聚甲基丙烯酸-β-羟乙酯载体上。研究了低温辐射聚合固定化的条件;讨论了不同固定化酶对淀粉转化成还原糖的相对活性及其重复使用的稳定性;探索了载体微孔结构与固定化酶活性的关系。结果表明,在真空体系内,酶用量≥250μg/mL、单体浓度在30％～40％之间,于-50℃～-55℃范围内进行5.6×10~5rad剂量的辐射聚合,所得固定化酶重复使用10多次其相对活性仍可保持在30％以上。     

Preparation and evaluation of OV-240-OH coated glass capillary columns for isomer specific determination of PCDDs and PCDFs

Glass capillaries were leached, dehydrated, persilylated with 1, 3-bis (3-cyanopropyl) tetramethyldisiloxane, and coated with OV-240-OH. After crosslinking and binding the phase to the glass surface the columns showed high separation efficiency, high temperature stability, and inertness comparable to persilylated apolar columns. Column performance is shown to be superior to liquid phase cyanopropyl columns such as SP 2330. The excellent separation capabilities together with the selectivity of the phase makes OV-240-OH coated columns a valuable tool for the determination of toxic isomers in complex mixtures of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The order of elution of individual TCDD isomers was found to be similar to that described for SP 2330 or Silar 10c. The detection of PCDDs and PCDFs in a fly ash extract further illustrates the utility of OV-240-OH coated columns. The high temperature limit of these columns opens the way for the analysis of high boiling compounds such as mixed brominated/chlorinated dibenzo-p-dioxins and dibenzofurans.     

A Study of the Hydrolysis of Waste Paper Cellulose with a Vertically Hanging Immobilized Cellulase Reactor and the Reuse of the Immobilized Cellulase

A commercialized cellulase from Trichoderma reesei has been successfully immobilized by using calcium alginate gel in our laboratory. The waste paper cellulose was hydrolyzed with a special design of the reactor to form a vertically hanging immobilized cellulase under the optimum conditions of pH 4.0 and 45 °C. Glucose, cellobiose and xylose are the major hydrolysis products. The glucose production from the hydrolysis with the vertically hanging immobilized cellulase was about 1.73‐fold better than the freely suspended immobilized cellulase. The average diameter of the immobilized cellulase pellets was 4.190 ± 0.291 mm. UV light irradiation deactivates the activity of the immobilized cellulase. The advantage of the vertically hanging immobilized cellulase reactor is an easy recycle and reuse of the immobilized cellulase. Washing and soaking the recycled immobilized cellulase with distilled water for one day can restore its activity to a small extent. Overall, the application of the hanging immobilized cellulase reactor for waste paper cellulose hydrolysis is successful.     

聚ε-己内酯的微米硅球固定化猪胰脂肪酶促合成

本文采用微米硅球固定化猪胰脂肪酶为催化剂合成聚ε-己内酯, 以期获得具有较高分子量、 良好生物相容性和使用安全性的生物可降解医用高分子材料.