海藻酸钠固定化根霉脂肪酶的制备及其性质

 研究了以海藻酸钠为载体,用包埋法制备固定化德氏根霉(Rhizopus delemar)脂肪酶的条件. 将酶粉和海藻酸钠溶于pH 5.0的HAc-NaAc缓冲溶液,用注射器将此混合液滴入到0.05 mol/L无菌CaCl2溶液中,静置固化45 min, 经过滤、洗涤和干燥后得到球状固定化酶. 固定化酶的活力回收约为34.1%. 酶学性质研究表明,此固定化酶的热稳定性较好. 游离酶在 60 ℃下保温1 h已完全丧失活力,而固定化酶在100 ℃下保温1 h仅损失36.2%的活力,在100 ℃下保温6 h仍可保持46.8%的酶活力. 酶经固定化后,其橄榄油水解反应的最适温度由40 ℃上升至90 ℃, Km值由13.8 mg/ml下降为8.1 mg/ml. 常见有机溶剂对固定化酶的活力影响较小. 将该固定化脂肪酶用于非水溶剂中正戊酸异戊酯的合成,重复使用6次后,固定化酶仍保持95%的酶活力.     

Application of magnetic poly(styrene-glycidyl methacrylate) microspheres for immunomagnetic separation of bone marrow cells

Surface-functionalized magnetic poly(styrene-glycidyl methacrylate) (PS-GMA) microspheres were prepared and coupled with Sca-1 antibody for cell selection from murine bone marrow mononuclear cells (MNCs). Biotinylated Sca-1 antibody could be directly coupled to avidin-bound magnetic microspheres. Alternatively, oxidized goat anti-mouse antibody was covalently bound onto the amino group-containing magnetic microspheres in a site-directed manner, and the resultant conjugate was coupled with non-modified Sca-1 antibody. Using the indirect antibody-bound magnetic microspheres, the purity of isolated Sca-1⁺ cells increased with bead-to-cell ratio. Using a bead-to-cell ratio of 10 beads/cell, a purity of 85% Sca-1⁺ cells corresponding to a 17-fold enrichment was achieved.     

Synthesis and characterization of chemically anchored adenosine with PHEMA grafted gold nanoparticles

The synthesis of chemically anchored adenosine with biocompatible poly(2-hydroxylethyl methacrylate) grafted gold nanoparticles (Ado-i-PHEMA-g-AuNPs) was realized by employing a simple strategy. Disulfide-containing poly(2-hydroxylethyl methacrylate) (DT-PHEMA) was initially synthesized by atom transfer radical polymerization (ATRP). The formation of DT-PHEMA was confirmed by ¹H-NMR and FT-IR. The molecular weight and molecular weight distribution were found to be 9.6 kg/mol and 1.40 from GPC analysis. DT-PHEMA was subsequently used for the synthesis of PHEMA-g-AuNPs by a grafting to protocol. The grafting of DT-PHEMA on the surface of AuNPs was confirmed by FT-IR, TGA, XPS, and EDX analyses. The particle size of the PHEMA-g-AuNPs was found to be ca. 5.0 nm from HR-TEM analysis. Boronic acid was used for functionalization of PHEMA-g-AuNPs, which was then subjected for covalent immobilization with adenosine via strong interaction between free hydroxyl groups of adenosine and boronic acid. Characterization and properties of the Ado-i-PHEMA-g-AuNPs were investigated by taking advantage from FT-IR, XPS, EDX, and UV-visible spectroscopy. The Ado-i-PHEMA-g-AuNPs nanocomposite exhibits a surface plasmon resonance peak at 586 nm which is red shifted from AuNPs (521 nm), indicating significant changes of surface property upon PHEMA-adenosine immobilization onto the surface of AuNPs.     

溶胶凝胶法制备固定化酶柱并应用于化学发光型的葡萄糖传感器

溶胶凝胶过程以期纯度高，均匀性强，处理温度低，反应条件易于控制等优点成为生物传感器中一种颇具前途的固化方法。利用硅酸乙酯的溶胶凝胶化过程对葡萄糖氧化酶进行固化，并制备了不同载体下的ＧＯＤ酶柱。实验结果表明ＧＯＤ可在ＳｉＯ２的溶胶凝胶体中保持较高的活性。     

Using open‐tubular capillary electrochromatography with part‐coating column for binding constants determination of β2‐adrenergic receptor with seven drugs

An open‐tubular capillary electrochromatography method has been developed for the determination of binding constants between β₂‐adrenergic receptor (β₂‐AR) and seven drugs. β₂‐AR was oriented immobilized onto one part of inner surface of capillary via microwave‐assisted technical synthesis. According to the linear relationship between coating length and the apparent mobility of analyte, the binding constant (K_b) can be obtained by related theories and equations. The order of K_b values between drugs such as adrenaline hydrochloride, norepinephrine bitartrate, and propranolol hydrochloride with β₂‐AR is well consistent with that reported in the literature. By the method, K_b values between four extracts of Radix Paeoniae Rubra and β₂‐AR were also successfully obtained. Subsequently, computer models were applied to interpret the CEC experiments. And the results proved to be in good agreement with the method. The work, herein, demonstrates the potential of the method in drug‐receptor affinity interactions evaluation and screening of lead compounds from natural sources.     

糖芯片最新研究进展

糖芯片是一种快速、高效、高通量获取糖-生物大分子相互作用信息的生物检测技术,对后基因组时代糖生物学的发展具有重大影响。本文主要论述了糖芯片固定化技术的最新进展,包括未经化学修饰的糖的化学固定,天然糖库及其固定,复杂寡糖的合成及其固定,糖基的密度差异固定化技术以及间隔基的引入技术。这些新的固定化技术保持了糖的化学结构,扩大了糖芯片的来源和应用范围,进一步提高了糖芯片的检测效率。此外,本文还介绍了虚拟筛选技术在这一领域的应用潜力以及糖芯片在医疗诊断等方面的应用,最后对糖芯片技术遇到的挑战和发展做了展望。     

壳聚糖修饰纳米纤维膜表面对氧化还原酶行为的影响

采用静电纺丝法制备了丙烯腈/丙烯酸共聚物(PANCAA)纳米纤维膜, 研究了纺丝液浓度对纤维形态的影响, 以扫描电子显微镜观察纤维形貌, 遴选得到最佳纺丝条件. 以1-乙基-3-(N,N-二甲基氨基丙基)碳二亚胺/N-羟基丁二酰亚胺(EDC/NHS)为偶联剂, 在纤维膜表面引入壳聚糖修饰层, 采用衰减全反射傅里叶变换红外光谱(ATR/FTTIR)、水接触角和称重法考察了修饰前后膜的变化. 通过戊二醛将过氧化氢酶固定到壳聚糖修饰的PANCAA纳米纤维膜上, 研究了壳聚糖及戊二醛浓度对固定化过氧化氢酶的影响, 结果表明, 在壳聚糖浓度为25 mg/mL及戊二醛质量分数为5%条件下, 壳聚糖修饰膜的固定化酶活性比空白膜提高了41.7%, 稳定性也得到了不同程度的提高.     

漆酶在纳米金溶胶/多重壁碳纳米管复合载体上固定方法的比较及粒子尺寸效应

以纳米金溶胶（NGS）和多重壁碳纳米管（MWCNTs）的共混物(NGS/MWCNTs)作为固定漆酶的载体,研究了3种固定漆酶方法在酶固定量、比活力上的差异。 研究了不同的固定方法对固定酶热稳定性和重复使用性及纳米金溶胶颗粒粒径对酶固定量和固定酶动力学参数的影响。 实验结果表明,NGS/MWCNTs具有良好的固定漆酶能力和高固酶比活力,NGS/MWCNTs（NGS粒径37 nm）通过简单物理吸附法固定漆酶的量和固酶的比活力最高,分别可达33.80 mg/g和9.433 U/mg。 在NGS-MWCNTs上采用化学键合方法固定的漆酶在70 ℃放置2 h后仍然保持初始活力的75％,重复使用20次后仍保持初始活力的70％。 纳米金溶胶粒子越小（24 nm）,底物和固定漆酶间亲和力越好（KM=0.027 mmol/L）,表观速率常数越大。