基于SOI基底的高通量细胞电融合芯片

提出了一种以MEMS技术为基础, 可在低电压驱动条件下工作的创新型细胞电融合芯片. 该芯片的设计原理在于通过缩短微电极间的间距, 在低电压条件下获得足够强度的排队和融合电场强度. 原型芯片以SOI硅片为加工材料, 通过刻蚀方式在顶层低阻硅形成微电极和微通道; 在微电极上沉淀2 μm厚的铝膜以降低电阻率, 提高导电性; 通过PECVD方法形成150 nm厚SiO2保障铝膜的抗腐蚀性及芯片生物相容性; 芯片最终采用DIP法进行封装. 在该芯片上进行了低电压(传统电融合设备工作电压的1/20)驱动条件下的基于介电电泳的细胞排队实验及后期的细胞电融合实验, 结果表明, 细胞多以两两结合的方式排列, 与传统的细胞融合电仪器相比较, 降低了多细胞排队概率, 进而减少了传统电融合设备多细胞融合的概率, 为细胞高效率融合奠定了基础. 在加载的低电压短脉冲信号后, 微通道中形成了高压短脉冲电场, 在脉冲作用下, 烟草原生质体细胞在微通道中发生了融合, 融合时间(2 min)远低于传统电融合方法(10~30 min), 融合率远远高于传统的PEG方法(融合率小于1%)和传统电融合方法(利用BTX ECM 2001细胞电融合系统得到, 融合率小于5%).     

烟草叶肉原生质体的漂浮电介质电泳研究

本文根据电介质电泳理论,首次对单个烟草叶肉细胞原生质体进行了电介质电泳漂浮实验。对单个原生质体在频率10Hz—15MHz的范围内测定了不同电导率(12.5μs/cm—520μs/cm)下的电介质电泳频谱,并根据实验数据计算了单个原生质体的膜电容C_m,数值为0.40±0.03μF/cm~2。本文还根据实验数据对细胞电融合过程中的原生质体偶极相互作用进行了分析,得出当施加外电场E_c=1.5kV/cm的情况下,两细胞之间的偶极相互作用压力π_d在频率高于20kHz时将显著地大于膜电压产生的压力π_m,成为膜穿孔的主要原因,这将为改进细胞电融合方案提供了新的依据。     

纳米TiO2表面对Cd2+的吸附与光化学还原过程的QCM研究

用石英晶体微天平(QCM)现场技术研究了Cd2+在纳米TiO2表面的吸附与光化学还原过程.研究结果表明,Cd2+在纳米TiO2表面的吸附量受溶液的浓度、pH值和不同添加物的影响.当pH<7时, Cd2+不发生吸附;pH＝7时,Cd2+在TiO2膜上的吸附量接近于15.2 mg/g.在紫外光光照下, Cd2+不发生光化学反应,但在溶液中加入NO-3和HCO-2后, Cd2+在电极表面可发生光化学反应,分别生成了CdO·Cd(OH)2和Cd.当醇类物质加入后, QCM的频率略有下降, 但没有观察到单质Cd的生成.     

表面活性素单分子膜在空气/水界面的迟滞现象

表面活性素是一类具有较强表面活性的微生物脂肽类化合物,能在空气/水界面形成不溶性单分子膜.利用Langmuir膜天平测定了表面活性素单分子膜的压缩-扩张循环曲线,发现单分子膜在经历了“平台区”后出现较大的迟滞环,迟滞环的形状与亚相pH有关.将“平台区”的单分子膜转移到云母表面后,用原子力显微镜(AFM)和扫描电子显微镜(SEM)均观察到高度达几十至数百纳米的表面聚集体,说明表面活性素在单分子膜的“平台区”伴随着自聚集.研究结果表明,表面活性素单分子膜在空气/水界面的迟滞现象是分子浸入亚相和形成三维表面聚集体共同作用的结果.     

Ru膜上Pt层的自发沉积及其在电化学表面增强红外光谱中的应用

采用自发沉积法在Ru膜上生成超薄Pt层(简称Ru/Pt膜), 即在开路状态下将电化学还原后的Ru膜浸于除去氧的H2PtCl6溶液中进行自发沉积. 电化学伏安法测量表明, 随着电还原-自发沉积循环次数的增加, 该Ru/Pt膜电极所含Pt组分增加, 且CO吸附层的电氧化峰电位较Pt膜电极上的明显负移. 应用现场衰减全反射表面增强红外光谱法(ATR-SEIRAS)可轻易检测到在该膜电极Pt和Ru位上吸附CO的振动谱峰. 所制Ru/Pt膜电极不仅对CO的电催化氧化具有协同效应, 还可应用于现场ATR-SEIRAS的研究中.     

混合表面活性剂水溶液的表面吸附 I.溴化十二烷基吡啶和硫酸十二烷基鈉的表面吸附

本工作研究澳化十二烷基呲啶(C_(12)NBr)和硫酸十二烷基钠(NaC_(12)S)两种正、负离子表面活性剂的混合溶液(加入溴化钠作成等离子强度溶液)的表面吸附。用滴体积法测定C_(12)NBr水溶液、等离子强度的、不同C_(12)Br-NaC_(12)S比例的水溶液及1:1当量C_(12)NBr-NaC_(12)S混合溶液的表面张力。利用等离子强度条件下的Gibbs吸附公式 -((dγ/dln m_N))_m_S=RTГ′_N及- -((dγ/dln m_N))_m_N=RTГ′_S,可分剧求出正、负表面活性离子的吸附量。结果表明: 1.负离子表面活性剂之存在大为增加正离子表面活性剂的表面活性;反之亦然。1:1当量C_(12)NBr-NaC_(12)S混合溶液的CMC约为2×10~(-5)m,比C_(12)NBr溶液的CMC约小650倍。 2.负离子表面活性剂之存在促进正表面活性离子的表面吸附;反之亦然。这恰好与负、负表面活性离子混合溶液及丁醇-负表面活性离子混合溶液之情形相反。 3.加无机盐(NaBr)对1:1当量C_(12)NBr-NaC_(12)S混合溶液的表面张力几无影响,亦即对吸附无显著影响。由此提出,对于无盐时的1:1C_(12)NBr-NaC_(12)S混合溶液,Gibbs吸附公式应为 -dγ/RT=(Г′_N+Г′_S)dlnm_N(或s) 4.1:1 当量混合溶液表面吸附的最小分子面积为16(?)~2(加NaBr)及15(?)~2(未加 NaBr)。因此可能有多分子吸附层的形成。此外,自实验结果的解析提出1:1当量混合溶液的表面无双电层;而正、负表面活性剂的高表面活性及高吸附量的产生,是由于长链间的van der Waals引力及正、负离子的静电引力的作用。     

不同浓度比的硫酸根和氯离子溶液中钝化膜的半导体特性转变机制研究

800合金作为核电站蒸汽发生器的一种关键材料,服役环境下其表面钝化膜的特性一直是人们研究的热点. 本文用Mott-Schottky方法研究了800合金在不同硫酸根离子和氯离子浓度比的溶液中钝化膜的半导体特性,并结合电化学阻抗谱（EIS）、扫描电镜（SEM）、扫描电化学显微镜（SECM）研究了钝化膜的耐蚀性和表面活性. Mott-Schottky结果表明,800合金表面钝化膜的半导体特性与溶液中硫酸根、氯离子的浓度比有关,随硫酸根与氯离子浓度比的降低,半导体特性发生转变. 当硫酸根与氯离子的浓度比较高时,钝化膜为p型半导体;而当硫酸根与氯离子的浓度比较低时,钝化膜为n型半导体. EIS、SECM、SEM结果表明,随浓度比的降低钝化膜由过钝化溶解转为明显的点蚀特征,钝化膜表面活性增加. 钝化膜特性的改变与其半导体类型的转变密切相关,而半导体特性的转变由氯离子、硫酸根离子在800合金钝化膜表面的竞争吸附所致,其在表面的竞争吸附直接影响钝化膜表面发生的化学反应,改变电极/溶液界面电势差,使钝化膜中的空位类型改变,最终决定半导体类型.     

不同浓度比的硫酸根和氯离子溶液中钝化膜的半导体特性转变机制研究

800合金作为核电站蒸汽发生器的一种关键材料,服役环境下其表面钝化膜的特性一直是人们研究的热点.本文用Mott-Schottky方法研究了800合金在不同硫酸根离子和氯离子浓度比的溶液中钝化膜的半导体特性,并结合电化学阻抗谱(EIS)、扫描电镜(SEM)、扫描电化学显微镜(SECM)研究了钝化膜的耐蚀性和表面活性.Mott-Schottky结果表明,800合金表面钝化膜的半导体特性与溶液中硫酸根、氯离子的浓度比有关,随硫酸根与氯离子浓度比的降低,半导体特性发生转变.当硫酸根与氯离子的浓度比较高时,钝化膜为p型半导体;而当硫酸根与氯离子的浓度比较低时,钝化膜为n型半导体.EIS、SECM、SEM结果表明,随浓度比的降低钝化膜由过钝化溶解转为明显的点蚀特征,钝化膜表面活性增加.钝化膜特性的改变与其半导体类型的转变密切相关,而半导体特性的转变由氯离子、硫酸根离子在800合金钝化膜表面的竞争吸附所致,其在表面的竞争吸附直接影响钝化膜表面发生的化学反应,改变电极/溶液界面电势差,使钝化膜中的空位类型改变,最终决定半导体类型.     

微电极阵列芯片的脂质体电融合研究

利用旋转蒸发法制作基于大豆卵磷脂的一种大型脂质体,在微电极阵列芯片上进行脂质体电融合实验研究.在电融合过程中,利用介电电泳力实现脂质体在微流控芯片中的排队,再利用高场强的电脉冲使脂质体膜发生可逆性电穿孔,在持续的介电电泳力作用下,使穿孔的脂质体实现融合.芯片上脂质体的融合率可以达到20％左右.而且,玻璃基底材料和低深宽比的通道结构更有利于脂质体融合过程的观察与控制.     

聚苯乙烯胶乳的表面电性质与表面活性离子的吸附

根据电泳与电导的测量得出,聚苯乙烯胶乳质点的ξ电势随电解质浓度增加而变大,主要是质点表面基团与溶液间离子交换的结果。根据Langmuir吸附公式与Stern双电层模型,由电泳数据求出了表面活性阳离子在聚苯乙烯胶乳上的吸附自由能与吸附位数。增大电解质浓度使质点表面吸附位数增加,表面活性阳离子的吸附量也因此变大。     

Influence of additives on the protoplasts electrofusion.

Various neutral or charged surface active substances were used for testing the influence of additives on the electrofusion of barley protoplasts. It was found that neutral surface active agents DX, TAGB, Span-80 and AEO-9 could promote the electrofusion. The positively charged surface active agents Bardac 2080, Bardac 2280 and amphoteric surface active agents dodecyl-propyl betaine and CAB betaine also promote the electrofusion, but at high concentration the electrofusion efficiency will reduce. The negatively charged polymer agents Cibacron blue DX, Fluoresceinylthiocarbamoyl DX, and active surface substances K12 and Carsonol TLS- presented negative effect. These phenomena were discussed from the view of adsorption of additives on the membrane and the interactions between protoplasts.     

葡聚糖及其衍生物对大麦细胞电融合的影响

葡聚糖及其衍生物对大麦细胞电融合的影响①王伟江志裕＊（复旦大学化学系上海２００４３３）细胞融合是指用人工方法使两个细胞融合成一个细胞的过程［１,２］．体细胞融合可在不同种,不同属,甚至更远的生物间进行,所得到的细胞可具有新的特性．对于植物细胞,有望通...     

Electroporation and fusion modified by nucleic acids and complexes

The study of biopolymer modified electrofusion has been extended to nucleosides, nucleotides, polynucleotides, nucleic acids and their complexes with positively charged ligands (Ca²⁺, La³⁺, ethydiumbromid, daunomycin, poly-l-lysine, histone). Whereas the mononucleotides show different effects on the electrofusion of barley protoplasts, the behaviour of the polymers are quite similar: at low concentrations the electrofusion was enhanced remarkably and at higher concentrations (>0.05 mg ml⁻¹) an inhibition effect was detected. Shielding the negative charge of phosphate groups the DNA complexes increase F_r values to some extend. Quite strong enhancement of F_r was also measured with nucleoproteins, e.g., nucleohistone. The essential process is the interaction between the polymers and the negatively charged protoplast membrane. This interaction was compared with the adsorption behavior of these polymers on the negative mercury electrode surface which can serve as a model for a `half membrane'. With these results a first system of `biopolymer modified electrofusion' is now available.     

Catalytic properties of silver nanoparticles supported on silica spheres

In this work, we investigate the catalytic properties of silver nanoparticles supported on silica spheres. The technique to support silver particles on silica spheres effectively avoids flocculation of nanosized colloidal metal particles during a catalytic process in the solution, which allows one to carry out the successful catalytic reduction of dyes. The effects of electrolytes and surfactants on the catalytic properties of silver particles on silica have been investigated. It is found that the presence of surfactants depresses the catalytic activity of the silver particles to some extent by inhibiting the adsorption of reactants onto the surface of the particles. Electrolytes either increase the migration rate of reactants in the solution resulting in an increase in the catalytic reaction rate or inhibit the adsorption of reactants onto the surface of the silver particles leading to a loss in the activity of the metal particles.     

The kinetic and thermodynamic study of the removal of Cr(VI) ion from aqueous solution by human hair waste

The removal of Cr(VI) ions from aqueous solution by human hair waste is investigated by using UV–Vis spectrophotometer technique. The morphological analysis of the human hair was also investigated by the scanning electron microscopy, Fourier transforms infrared spectroscopy and X-ray photoelectron spectroscopy. The influence of various physicochemical effective parameters such as pH, ionic strength, adsorbent amount, contact time, initial concentration of metal ion on removal of Cr(VI) ions by human hair process was also studied. The optimum conditions for this adsorption process were obtained at pH = 2 and contact time of 150 min while the highest Cr(VI) uptake is recorded for 0.5 g of the adsorbent per 100 ml of solution. Three isotherms models including Langmuir, Freundlich and Temkin were applied to describe the equilibrium data. It was found that the experimental data were well described by Freundlich isothermal model. The maximum adsorption capacity was found to be 11.64 mg g^?1.The thermodynamic study data showed that the adsorption process of Cr(VI) on human hair is an endothermic, spontaneous and physisorption reaction. The kinetics of the adsorption process was studied using three kinetics models including Lagergren-first-order, pseudo-second-order and Elovich model. The obtained data are indicated that the adsorption processes of Cr(VI) over human hair could be described by the pseudo-second-order kinetic model.     

Polylysine supports electrofusion

A series of poly-l-lysine fractions (mean molecular masses M_m from 3970 to 132 300) at extremely low concentrations in the nanomolar range were combined with dielectrophoresis and rectangular pulsation of barley protoplasts in order to support electrofusion of membranes. Contrary to our results with dextran fractions, the poly-l-lysine fractions of high molecular masses M_m promote the synergistic effect of polymer-supported electrofusion yield more than two times. The M_m dependence of adsorption at the dropping mercury electrode is analogous to that of dextran; however, instead of a Langmuir(-Freundlich) isotherm a Frumkin type was found, because of intermolecular interaction in the adsorption layer. Therefore the adsorption mechanisms for the two biopolymers are contradictory in this respect. Again it was shown that such electrofusion experiments provide a sensitive test for two kinds of interactions between biopolymers and membranes. Moreover, the practical advantage for moderate electrofusion is the following: in presence of 10 μg ml⁻¹ (= 10^−3%) poly-l-lysine (M_m, 26300) the electrofusion yield (F_r=2.2) is the same as in polymer-free treatment with only one pulse, which must be 250 V cm⁻¹ higher. Finally, some possible mechanisms are proposed.     

辛烷基二甲基苄基季铵盐离子液体对Q235钢的缓蚀性能

利用失重分析、 极化曲线、 电化学阻抗谱和扫描电子显微镜等研究了辛烷基二甲基苄基季铵盐离子液体(ODBA)对1 mol/L盐酸溶液中Q235钢的缓蚀性能, 并分析了其在Q235钢表面的吸附行为. 失重分析结果表明, 随着ODBA浓度的增加, 缓蚀效率逐渐提高, 在ODBA质量浓度为0.2 g/L、 温度为30 ℃时, 缓蚀效率可达95.53%; 电化学测试结果与失重分析结果一致; 热力学研究结果表明, ODBA在碳钢表面的吸附是放热过程, 且遵循Langmuir吸附等温线, 是以化学吸附为主的混合型吸附; 同步热分析测试表明ODBA具有良好的热稳定性.     

ANTIFOULING PROPERTIES OF POLYVINYL CHLORIDE) MEMBRANES MODIFIED BY AMPHIPHILIC COPOLYMERS P(MMA-A-MAA)

Three well-defined diblock copolymers of poly(methyl methacrylate-b-methacrylic acid)(P(MMA-b-MAA))were synthesized using atom transfer radical polymerization method and varying poly(methacrylic acid)(PMAA)chain lengths. These copolymers were blended with PVC to fabricate porous membranes via phase inversion process.Membrane morphologies were observed by scanning electron microscopy(SEM),and chemical composition changes of the membrane surfaces were measured by X-ray photoelectron spectroscopy(XPS).Static and dynamic protein adsorption experiments were used to evaluate antifouling properties of the blend membranes.It was found that,the blend membranes containing longer PMAA arm length showed lower static protein adsorption,higher water permeation flux and better protein solution flux recovery.     

聚丙烯微孔膜表面肝素化及其对低密度脂蛋白的吸附特性

为了赋予聚丙烯微孔膜(PPMM)选择性吸附低密度脂蛋白(LDL)的能力,发展了一种有效的PPMM表面共价固定肝素的方法.基于紫外引发丙烯酸的接枝聚合,通过碳二亚胺活化,以乙二胺为间隔臂,将肝素共价固定于PPMM表面,获得表面肝素化的PPMM.ATR-FTIR和XPS分析确证了修饰过程中膜表面基团及化学成分的变化.采用静...     

Electrofusion of an industrial Baker’s yeast strain with a sour dough yeast

A method for hybridization of yeast protoplasts ofSaccharomyces cerevisiae andCandida holmii by electrofusion was optimized. The hybrids were screened on maltose-acetate agar plates. The average fusion frequency was 1.1xl0-³. Two hybrids of 132 collected from selection plates were found to be stable over 15 sequential shake flask cultivations. However, the strains reverted during production of baker’s yeast in a laboratory scale process imitating the industrial process.