Amphiphilic block and statistical copolymers with pendant glucose residues: Controlled synthesis by living cationic polymerization and the effect of copolymer architecture on their properties

Amphiphilic block and statistical copolymers of vinyl ethers (VEs) with pendant glucose residues were synthesized by the living cationic polymerization of isobutyl VE (IBVE) and a VE carrying 1,2:5,6‐di‐O‐isopropylidene‐D ‐glucose (IpGlcVE), followed by deprotection. The block copolymer was prepared by a two‐stage sequential block copolymerization, whereas the statistical copolymer was obtained by the copolymerization of a mixture of the two monomers. The monomer reactivity ratios estimated with the statistical copolymerization were r₁ (IBVE) = 1.65 and r₂ (IpGlcVE) = 1.15. The obtained statistical copolymers were nearly uniform with the comonomer composition along the main chain. Both the block and statistical copolymers had narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight ∼ 1.1). Gel permeation chromatography, static light scattering, and spin–lattice relaxation time measurements in a selective solvent revealed that the block copolymer formed multimolecular micelles, possibly with a hydrophobic poly(IBVE) core and a glucose‐carrying poly(VE) shell, whereas the statistical copolymer with nearly the same molecular weight and segment composition was molecularly dispersed in solution. The surface properties of the solvent‐cast films of the block and statistical copolymer were also investigated with the contact‐angle measurement. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 459–467, 2001     

Controlled synthesis of amphiphilic block copolymers with pendant glucose residues by living cationic polymerization

Amphiphilic block copolymers of vinyl ethers (VEs) of the type —[CH₂CH(OCH₂CH₂OR)]_m—[CH₂CH(OiBu)]_n—were synthesized by living cationic polymerization, where R is a D-glucose residue, and m and n are the degrees of polymerization (m = 20–50; n = 11–89). To obtain them, sequential living block copolymerization of isobutyl vinyl ether (IBVE) and the vinyl ether carrying 1,2:5,6-diisopropylidene-D -glucose residue was conducted by using the HCl adduct of IBVE, CH₃CH(OiBu)Cl, as initiator in conjunction with zinc iodide. These precursor block copolymers had a narrow molecular weight distribution (M̄_w/M̄_n ∼ 1.1) and a controlled composition. Treatment of them with a trifluoroacetic acid/water mixture led to the target amphiphiles. The solubility of the amphiphilic block copolymers in various solvents depended strongly on composition or the m/n ratio. Their solvent-cast thin films were observed, under a transmission electron microscope, to exhibit various microphase-separated surface morphologies such as spheres, cylinders, and lamellae, depending on composition. © 1997 John Wiley & Sons, Inc.     

Quantitative Determination of Urine Glucose: Combination of Laminar Flow in Microfluidic Chip with SERS Probe Technique

A surface-enhanced Raman scattering(SERS) sensing approach for urine glucose was developed based on the laminar flow technology in a cross-type microfluidic chip with SERS probes, 4-mercaptophenylboronic acid (MPBA) functionalized Ag nanoparticles. MPBA as the glucose receptor can identify and bind up with glucose at a molar ratio of 2:1, which can cause the aggregation of SERS probes at a certain position of the chip channel and further enhance the SERS signal of MPBA significantly. Thus, the quantitative SERS detection of glucose was achieved indirectly. No sample pretreatment and separation were needed in this method since the SERS detection was achieved in the gradient diffusion and molecular recognition processes between urine glucose and SERS probe in the laminar flow, which simplified the sample treatment procedures, saved detection time and made it feasible for clinic applications. This method shows a good linear relationship within human body's normal physiological range and has high sensitivity and selectivity. The lowest detection concentration can reach 1.0 mg/dL.     

Influence of Dietary Chitosan Feeding Duration on Glucose and Lipid Metabolism in a Diabetic Rat Model

This study was designed to investigate the influence of dietary chitosan feeding-duration on glucose and lipid metabolism in diabetic rats induced by streptozotocin and nicotinamide [a non-insulin-dependent diabetes mellitus (NIDDM) model]. Male Sprague-Dawley rats were used as experimental animals and divided into short-term (6 weeks) and long-term (11 weeks) feeding durations, and each duration contained five groups: (1) control, (2) control + 5% chitosan, (3) diabetes, (4) diabetes + 0.8 mg/kg rosiglitazone (a positive control), and (5) diabetes + 5% chitosan. Whether the chitosan feeding was for 6 or 11 weeks, the chitosan supplementation decreased blood glucose and lipids levels and liver lipid accumulation. However, chitosan supplementation decreased plasma tumor necrosis factor (TNF)-α, insulin levels, alanine aminotransferase (ALT) activity, insulin resistance (HOMA-IR), and adipose tissue lipoprotein lipase activity. Meanwhile, it increased plasma high-density lipoproteins (HDL)-cholesterol level, plasma angiopoietin-like-4 protein expression, and plasma triglyceride levels (at 11-week feeding duration only). Taken together, 11-week (long-term) chitosan feeding may help to ameliorate the glucose and lipid metabolism in a NIDDM diabetic rat model.     

基于多层叉指超微带电极阵列的葡萄糖传感器

采用多层工艺和光刻方法在玻璃衬底上加工了亚微米级金叉指型超微带电极阵列（IDA）,IDA电极的宽度为362nm,电极表面位于沟槽内。实验表明,所加工的IDA电极可作为生物和化学传感器的一次性超微基体电极。采用电聚合的方法将葡萄糖氧化酶（GOD）和吡咯（PPy）固定于IDA电极,该修饰电极可作为葡萄糖传感器。采用该葡萄糖传感器对磷酸钾缓冲溶液（pH7．0）中的葡萄糖浓度进行了比对测量,在2．0-7．0mmol／L的浓度范围内,传感器的响应时间为10s;灵敏度为14．6nA／（mmol／L）,相关系数为0．999。     

微阀进样和固定化试剂化学发光微流动注射芯片的研究

设计了一种将微注样阀和发光试剂均集成化的微流动注射化学发光芯片。利用luminolK3Fe(CN)6H2O2化学发光体系,研究了这种芯片的分析特性。该芯片测定H2O2的线性范围为2×10-5～8×10-9mol/L;检出限为3.6×10-9mol/L;相对标准偏差RSD=4.4%(c=1×10-6mol/L,n=11)。与常规的流动注射化学发光分析法相比,该芯片具有简单、快速、灵敏度高、耗样量少等特点,并结合酶促反应成功地用于人体血清中葡萄糖的测定。     

Ru-B/SiO2非晶态催化剂应用于液相葡萄糖加氢制山梨醇

 采用浸渍法结合KBH4还原法制备了Ru-B/SiO2非晶态催化剂(3.14%Ru),并将其用于液相葡萄糖加氢制山梨醇反应. 结果表明,该催化剂具有良好的热稳定性,且其催化活性远高于Raney Ni和Ni-B/SiO2非晶态催化剂,山梨醇的选择性接近于100%,显示出良好的工业化应用前景. 通过与晶态Ru-B/SiO2及Ru/SiO2的催化活性进行比较,并结合ICP,XRD,DSC,SEM,XPS及氢吸附等表征结果,初步讨论了非晶态合金结构和表面电子态对催化剂活性的促进作用.     

铂修饰超细纤维聚苯胺在葡萄糖生物传感方面的应用

在不锈钢电极(SS)表面制得超细纤维状聚苯胺(superfine-fibrous PANI),经Pt微粒修饰后得到Pt微粒超细纤维聚苯胺复合电极[Pt／(superfine-fibrous PANI)／SS]。结果表明,直径50-100nm的Pt微粒均匀分布于直径约100nm的聚苯胺纤维上;Pt／(superfine-fibrous PANI)／SS电极对H2O2氧化具有很好的电催化活性。采用脉冲电流法(PGM)再将葡萄糖氧化酶(GOD)与间苯二胺(MPD)混合共聚嵌于Pt／(superilnefibrous PANI)／SS电极表面,获得了具有优异生物电化学传感特性的葡萄糖氧化酶电极。该酶电极最大响应电流密度im=917．4μA／cm^2,米氏常数K=9．339mmol／L;酶电极对葡萄糖响应快,对尿酸和抗坏血酸有很好的抗干扰性能。     

壳聚糖固定化葡萄糖氧化酶生物传感器测定葡萄糖的含量

应用壳聚糖将葡萄糖氧化酶固定于鸡蛋膜上,结合氧电极制得葡萄糖传感器.实验表明,壳聚糖比戊二醛能更好地固定葡萄糖氧化酶,最佳条件为壳聚糖浓度0.3%、固定化酶量0.8 mg、 pH 7.0、缓冲溶液浓度300 mmol/L和温度25 ℃.本葡萄糖传感器的线性范围为0.016～1.10 mmol/L;检出限为8.0 μmol/L(S/N=3), 响应时间<60 s,有很好的稳定性,寿命>3个月.同一个传感器重复使用以及同方法制作的不同传感器之间都有很好的重现性,RSD分别为2.5%(n=10)和4.7%(n=4).实际样品中可能存在的烟酰胺、 VB6、 VB12、 VE、Ca2+、 Mg2+、 K+和Zn2+等对葡萄糖的测定不产生干扰.本传感器已成功地应用于市售饮料中葡萄糖含量的测定.