原子力显微镜在生物物理领域的新应用

介绍了原子力显微镜在生物物理领域的最新应用:蛋白质去折叠、DNA拉伸、生物膜受力,通过分析实验得到的力谱,可以获取关于蛋白质、DNA、生物膜结构信息.原子力显微镜不仅能反映测量体系的力学性质,由于其具有独特的时间、空间分辨及实时成像,因而能提供更多信息.     

味觉电化学传感器的研究——Ⅰ.甜、酸、苦、咸物质对模拟生物膜电位振动频率的影响

本文以十六烷基三甲基溴化铵/含苦味酸的硝基苯/蔗糖溶液为研究体系,发现甜、酸、苦、咸物质均能使体系的振动波形和频率发生变化,初步建立了测定有味物质的定性、定量方法,并对该味觉电化学传感器的响应机理进行了探讨。     

鞘磷脂和神经节苷脂对磷脂酰乙醇胺混合脂超分子体系液晶态立方相Im3m和Pn3m结构影响的研究

用磷脂酰乙醇胺(DEPE)、鞘磷脂(Sphingomyeline, Sph)、神经节苷脂(Gm1)和胆固醇(Chol)模拟了生物膜超分子体系液晶态结构, 通过用小角X射线衍射(SAXD)对混合脂体系液晶态结构进行了研究, 鉴定出了两种立方相: 即Im3m(Q²²⁹)和Pn3m(Q²²⁴)结构. 实验发现, 鞘磷脂的含量对DEPE膜的结构有一定的影响, 随着鞘磷脂浓度的增加, 混合脂体系的液晶态结构发生了由Im3m(Q²²⁹)到Pn3m(Q²²⁴)的变化. 神经节苷脂(Gm1)的含量对混合脂体系的液晶态结构也有一定的影响, 当神经节苷脂(Gm1)含量达到某一临界值时, 混合脂体系的液晶态结构发生了从Im3m(Q²²⁹)到Pn3m(Q²²⁴) 的变化. 当DEPE-Shp-Gm1超分子聚集体中含有胆固醇时, 胆固醇的极性头部(—OH)与磷脂酰乙醇胺(DEPE)、鞘磷脂(Shp)、神经节苷脂(Gm1)的极性头部通过氢键相互作用形成液晶态立方相Im3m(Q²²⁹)结构, 再通过疏水/亲水相互作用形成稳定的Pn3m (Q²²⁴)结构.     

固定化脂质体色谱研究中药复方的细胞膜通透性成分及其质量控制

提出了固定化脂质体色谱(immobilized liposome chromatography,ILC)研究中药复方的细胞膜通透性成分及其质量控制的方法。以当归补血汤及其组分为例,考察了它们在ILC色谱柱上的分离效果;当归补血汤水提取液和75％乙醇提取液在ILC色谱柱上各有8个保留峰,当归水提取液、甲醇提取液和75％乙醇提取液在ILC色谱柱上分别有3、6、9个保留峰,黄芪水提取液、甲醇提取液和75％乙醇提取液在ILC色谱柱上各有7个保留峰;建立了当归补血汤及其组分中阿魏酸和蒿本内酯的定量分析方法,当归补血汤水提取液和75％乙醇提取液中阿魏酸的含量分别为0．0743％和0．0688％,蒿本内酯的含量分别为0．0472％和0．457％,当归水提取液和75％乙醇提取液中阿魏酸的含量分别为0．0694％和0．0691％,蒿本内酯的含量分别为0．0781％和0．455％。     

Destabilization of artificial biomembrane induced by the penetration of tryptophan

The effect of tryptophan on the membrane stability was studied by using three artificial biological membranes including liposome, Langmuir monolayer and solid supported bilayer lipid membrane (s-BLM) as models. All the results indicate that the penetration of tryptophan can destabilize different artificial biological membranes. The diameter of liposome and the leakage of calcein from liposome increased with the increase of tryptophan concentration because the penetration of tryptophan was beneficial for dehydrating the polar head groups of lipids and the formation of fusion intermediates. π-A isotherms of lecithin on the subphase of tryptophan solution further confirm that tryptophan can penetrate into lipid monolayer and reduce the stability of lipid monolayer. When the concentration of tryptophan increased from 0 to 2 × 10⁻³ mol L⁻¹, the limiting molecular area of lecithin increased from 110.5 to 138.5 Å², but the collapse pressure of the monolayer decreased from 47.6 to 42.3 mN m⁻¹, indicating the destabilization of lipid monolayer caused by the penetration of tryptophan. The resistance spectra of s-BLM demonstrate that the existence of tryptophan leads to the formation of some defects in s-BLM and the destabilization of s-BLM. The values of electron-transfer resistance and double layer capacitance respectively decreased from 5.765 × 10⁶ Ω and 3.573 × 10⁻⁸ F to 1.391 × 10⁶ Ω and 3.340 × 10⁻⁸ F when the concentration of tryptophan increased from 0 to 2 × 10⁻³ mol L⁻¹. Correspondingly, the breakdown voltage of s-BLM decreased from 2.51 to 1.72 V.     

对一种接触氧化法新型填料性能的研究

阐述了接触氧化法中填料的发展状况及选择填料应遵循的原则,对一种新型悬浮填料的物理化学性质及生物附着量进行了研究,给出了相关的数据.结果表明,这种填料具有比较显著的优点.     

Interaction of polyacrylic acid with lipid bilayers: effect of polymer mass

Polyanion‐coated lipid vesicles are proposed to have an appreciable potential for drug delivery because of their ability to control the permeability of lipid bilayers by environmental parameters such as pH and temperature. However, details of the interaction of this class of polymers with lipids and their mechanisms of induced permeability are still being debated. In this work, we applied ¹H NOESY to study details of the interaction of polyacrylic acid (PAA) fractions of molecular weights 5 and 240 kDa with dimyristoylphosphatidylcholine vesicles. We showed that PAA of two different molecular masses modifies lipid bilayers increasing disorder and probability of close contact between polar and hydrophobic groups. PAA molecules adsorb near the interface of lipid bilayers but do not penetrate into the hydrophobic core of the bilayer and, thus, cannot participate in formation of transbilayer channels, proposed in earlier works. Increasing the molecular mass of PAA from 5 kDa to 240 kDa does not change the effect of PAA on the bilayer, although PAA240 forms a more compact structure (either intra‐molecular or inter‐molecular) and interacts more strongly with interface lipid protons. Copyright © 2013 John Wiley & Sons, Ltd.     

给水系统生物膜对公众健康的影响

分析了饮用水中微生物的类型,给出了饮用水中微生物的控制策略,重点阐述了给水系统生物膜对公众健康的影响,并提出了控制生物膜形成的有效方法。     

味觉电化学传感器的研究：甜味物质对模拟生物膜电位振荡的影响

本文以十六基三甲基溴化铵＋乙醇／含苦味酸的硝基苯／蔗糖溶液为研究体系，对影响该体电位振荡的各因进行了探讨，观察到各种甜味物质均能影该体系的振动波形和频率，并发现振荡频率的对数与各甜味物质浓度在一定范围内呈线性关系，初步建立了利用该体系测定甜味物的定笥，定量，工对该味觉电化学传感器的响应机理进行了。     

The hemocompatibility and the reabsorption function of TiO2 nanotubes biomembranes

A novel high-intensity TiO2 nanotubes array membrane was fabricated via electrochemical anodization of highly pure titanium foil and an open-ended TiO2 nanotubes array membrane was obtained by HF gas etching at the bottom of the nanotubes. Pig tubular epithelial cells (LLC-PK1) and vascular endothelial cells (ECV304) were cultivated on the open-ended TiO2 nanotubes surface through a mixing implantation method and TiO2 nanotubes biomembrane materials with physiological function were successfully produced. Hemocompatibility of glass slides, pure titanium, TiO2 nanotubes without cells and TiO2 nanotubes with culture cells were investigated by the plasma recalcification time method and reabsorption of sodium and potassium were measured by custom-designed devices. The results show that the hemocompatibility of the TiO2 nanotubes array membrane with culture cells was superior to the control group, and the biomembrane has an excellent reabsorption function. This demonstrates that a TiO2 nanotubes array membrane has excellent physiological function and is an ideal candidate material for biological dialysis.