大规模动物细胞固定化培养研究进展

基于固定化载体的生物反应器技术是动物细胞固定化培养的主要手段。综述了近年来微载体，微囊化，无载体细胞自絮凝以及膜等固定化技术在动物细胞固定化培养中的应用及其进展。同时对动物细胞固定化培养中的场效应、多腔室和多细胞混合培养体系进行初步的探讨。     

静电场对表面等离子体子共振DNA传感器灵敏度的影响

利用电场改变金膜表面固定化探针DNA的方位，从而影响了DNA杂交效率，进而影响了表面等离子体子共振DNA传感器的灵敏度。结果表明不同极性的电场对DNA传感器的作用不同：当金膜表面带负电荷时，探针DNA在电场的作用下直立在金膜上，空间位阻减小，提高杂交效率，从而使传感器的灵敏度提高，反之亦然。     

固定化细胞发酵—膜蒸馏耦合生产乙醇的研究

对固定化酿酒酵母细胞发酵与膜蒸馏耦合生产乙醇进行了实验研究,首先实验测定了平板蒸膜馏器的分离性能以及游离酵母细胞发酵动力学和固定化酵线细胞发酵动力学,然后将游离细胞发酵罐及固定化细胞反应器分别与平板膜蒸馏装置相耦合成膜生物反应器,对固定化细胞发酵－膜蒸馏分离乙醇耦合过程进行了研究。在游离酵母细胞发酵中,间歇培养１３ｈ发酵液中乙醇质量浓度,酵母细胞密度（单位体积发酵液内细胞个数）和葡萄糖转化率,乙醇     

葡萄糖氧化酶在丝素膜中的固定化及其性能和应用于生…

应用二咱中性盐溴化锂和氯化钙作为溶解蚕丝丝素的试剂，制成了二咱固定化葡萄糖氧化酶丝素膜。经酶比色法和红外分光光度法分析，结果表明这二种丝素膜都是良好的固定化酸疼的生物材料。葡萄糖氧化酶经这些线素膜固定以后对热和ＰＨ稳定性得到明显改良，这些酶膜性能稳定，具有高的活性得率，能长期存放。以这些固定化葡萄糖氧化酶丝素膜和氧电极为基础，研制的流动注射分析式电流型葡萄糖传感器性能较稳定，具有较宽的葡萄糖线性响     

多孔壳聚糖膜固定化脲酶活性的X射线微区分析

以邻苯二甲酸二丁酯为致孔剂,制备多孔壳聚糖膜,用作固定化脲酶的载体.利用X射线微区分析方法,对其活性进行了定位分析:以BaCl2为捕捉剂,在Tris-HCl缓冲溶液中,底物尿素经固定化脲酶催化水解产生NH3和CO2,后者和捕捉剂反应生成BaCO3,沉积在固定化脲酶的催化活性部位.结果表明:BaCl2可用作固定化脲酶活性定位的捕捉剂;多孔壳聚糖膜通透性好、比表面积大、载酶量高,脲酶均匀分布在膜的外表面和膜内的孔隙中.     

肝素共混丝素蛋白膜上AT-的固定化及其体外抗凝血性能

用抗凝血酶(antithrombin-Ⅲ,AT-Ⅲ)和肝素对生物材料进行表面改性,以提高其抗凝血性能.以低浓度肝素丝素共混蛋白膜为基质,利用等离子体处理辅助的共价交联方法对AT-Ⅲ进行固定化.用过剩法对固定化效果进行评价,固定化后的活性采用体外凝血时间进行检测,人血管内皮细胞在材料上的生长情况用MTT法测定.结果显示,通过该方法可以有效地将蛋白固定化,低浓度肝素丝素共混膜固定化AT-Ⅲ后,不仅其抗凝血性能有了一定的改善,而且与普通的肝素共混膜相比,细胞毒性也有所降低.该研究结果拓展了AT-Ⅲ蛋白的应用范围,同时为抗凝血材料的设计提供了一种新的思路.     

地质聚合物管状无机膜固定化碳酸酐酶用于CO2捕获

为了研究多孔材料对酶固定化性能的影响,提出了一种以地质聚合物管状无机膜为载体的新型酶固定化策略。利用该膜材料介孔中存在的大量硅羟基和铝羟基结构,采用戊二醛交联法成功地将碳酸酐酶负载到该无机介孔膜中。固定化实验结果表明：固定化酶复合膜的酶活性回收率可达63.7%。在稳定性测试中,该膜在连续使用30次后保持了67.8%的相对活性,在4℃下保存60 d后保持了52.0%的相对活性。在CO₂捕集试验中,CO₂捕集效率在固定化酶复合膜催化下提高了5.6倍。     

肝素共混丝素蛋白膜上AT-的固定化及其体外抗凝血性能

用抗凝血酶(antithrombin- ,AT- )和肝素对生物材料进行表面改性,以提高其抗凝血性能.以低浓度肝素丝素共混蛋白膜为基质,利用等离子体处理辅助的共价交联方法对AT- 进行固定化.用过剩法对固定化效果进行评价,固定化后的活性采用体外凝血时间进行检测,人血管内皮细胞在材料上的生长情况用MTT法测定.结果显示,通过该方法可以有效地将蛋白固定化,低浓度肝素丝素共混膜固定化AT- 后,不仅其抗凝血性能有了一定的改善,而且与普通的肝素共混膜相比,细胞毒性也有所降低.该研究结果拓展了AT- 蛋白的应用范围,同时为抗凝血材料的设计提供了一种新的思路.     

烯丙胺等离子体处理聚丙烯膜的酶固定化

以烯丙胺等离子体对聚丙烯膜表面进行处理后,利用表面生成的氨基功能基团进行过氧化物酶的固定化,所采用的固定化方法主要有吸附法、戊二醛交联法和分子识别法.结果表明通过等离子体处理后聚丙烯膜表面的氨基基团可以有效地提高酶固定化效率,其中分子识别法可以得到具有最高酶活和酶稳定性的固定化酶膜.     

固定化金属螯合亲和膜制备及其性能研究

将纤维素滤纸经碱处理,环氧活化,配基偶联和固定化Cu2 后制得了大 孔纤维素亲和膜,检验了亲和膜的流速与负压,等温吸附,保存方法及使用次数等亲和膜性能指标,设计了一种解决金属离子泄漏问题的新方法,得到的结果明显优于传统的凝胶柱,以上结果表明,普通纤维素滤纸可以制成性能优良的亲和膜色谱介质。     

DNA电化学传感器的研究进展

介绍了脱氧核糖核酸（DNA）电化学传感器的原理并重点评述了DNA在不同材料电极表面的固定化技术，对比了吸附法、共价键合法、自组装法、亲和素-生物素反应系统固定法以及组合法固定DNA在构建DNA电化学传感器中的特点．参考文献64篇．     

Controllable fabrication of Au micro/nanostructures on self-doped polyaniline nanofibers via electrochemical deposition and its application for DNA immobilization

Four electrochemical methods, cyclic voltammetric deposition, potentiostatic electrodeposition, multi-potential step electrodeposition and three-step electrodeposition, were used to fabricate Au micro/nanostructures on self-doped polyaniline nanofibers-coated glassy carbon electrodes (Au/nanoSPAN/GCEs). The Au micro/nanostructures deposited on the nanoSPAN-modified electrodes were shown by scanning electron microscopy to exhibit different morphologies, such as Au nanoparticle clusters, monodisperse nanoparticles and homogeneously dispersed flower-like microparticles, depending on the deposition method. This phenomenon demonstrates that control over the morphology of Au metal can be easily achieved by adjusting the electrodeposition method. The electrochemical behaviors of the Au/nanoSPAN/GCEs also varied with above four methods, which were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. In comparison with Au nanoparticle clusters and monodisperse Au nanoparticles, homogeneously dispersed flower-like Au microparticles had the largest surface area and obviously enhanced electrochemical response towards the redox reactions of [Fe(CN)₆]^3?/4? on the modified electrode. DNA immobilization on the Au/nanoSPAN/GCEs was investigated by differential pulse voltammetry using [Fe(CN)₆]^3?/4? as an indicator. The efficiency of DNA immobilization was inherently related to their different Au micro/nanostructure morphologies. The Au/nano-SPAN/GCE fabricated by three-step electrodeposition showed the largest capacity for immobilization of single stranded DNA, which makes it a promising DNA biosensor.     

Initiation and re-initiation of DNA unwinding by the Escherichia coli Rep helicase

Helicases are motor proteins that couple conformational changes induced by ATP binding and hydrolysis with unwinding of duplex nucleic acid, and are involved in several human diseases. Some function as hexameric rings, but the functional form of non-hexameric helicases has been debated. Here we use a combination of a surface immobilization scheme and single-molecule fluorescence assays--which do not interfere with biological activity--to probe DNA unwinding by the Escherichia coli Rep helicase. Our studies indicate that a Rep monomer uses ATP hydrolysis to move toward the junction between single-stranded and double-stranded DNA but then displays conformational fluctuations that do not lead to DNA unwinding. DNA unwinding initiates only if a functional helicase is formed via additional protein binding. Partial dissociation of the functional complex during unwinding results in interruptions ('stalls') that lead either to duplex rewinding upon complete dissociation of the complex, or to re-initiation of unwinding upon re-formation of the functional helicase. These results suggest that the low unwinding processivity observed in vitro for Rep is due to the relative instability of the functional complex. We expect that these techniques will be useful for dynamic studies of other helicases and protein-DNA interactions.     

运用交流阻抗技术直接监测DNA杂交

介绍了基于交流阻抗技术构建非标记型脱氧核糖核酸（DNA）杂交传感器的方法.以24个碱基长度的寡聚DNA作为实验对象，将5′端巯基化的单链寡聚DNA（SH-ssDNA）探针与巯基乙酸（RSH）同时自组装到金电极表面，形成杂交识别层，利用交流阻抗技术测量出杂交前后金电极表面电子传递电阻R_et的增量作为杂交信号.实验中对DNA探针的自组装时间、杂交温度、杂交时间和阻抗测量液等实验条件进行了观察和优化；通过选择自组装液中SH-ssDNA探针和RSH的浓度，减少DNA在金电极表面的非特异性吸附，同时保证金电极表面自组装的SH-ssDNA探针有合适的疏密度，提高了杂交效率.在各优化条件下，无需扩增杂交信号，此非标记型DNA杂交传感器的检测下限为3.0×10^-14mol/L；和完全互补序列相比，一个和三个碱基错配序列分别产生55.6%和1.3%的杂交信号.     

酶学信号扩增方法定量检测生物素探针杂交

将靶核酸固定于微孔滴定板上，用化学方法标记的生物素探针进行杂交，采用底物－辅助因子循环信号扩增系统对杂交结果进行检测，结果表明用该信号检测系统的检验灵敏度比常用显色底物的检测灵敏度高１０倍。     

Pb2+的磷酸盐高效稳定化方法及模拟

为减少铅污染废物对环境和人体健康的影响,研究经济快速高效且对pH适应能力强的Pb2 稳定化方法。考察了3种磷酸盐CaHPO4、Ca(H2PO4)2、Na3PO4对水溶液中Pb2 的稳定化效果,比较了反应时间和初始Pb2 浓度变化对稳定化效果的影响,并采用Visual Minteq软件对反应进行模拟。结果表明:这3种磷酸盐均可通过生成沉淀的方式迅速完成Pb2 的稳定化,溶液中Pb2 去除率分别达96.9%、97.5%和100%。3种磷酸盐对Pb2 稳定化效率随着初始Pb2 浓度增加而升高,且Na3PO4处理效果最优。溶液pH升高有利于Pb2 的磷酸盐稳定化。     

杂交型DNA电化学生物传感器研究进展

杂交型DNA电化学生物传感器是一类利用核酸互补配对杂交原理检测和分析特定DNA序列的电化学生物传感器.由于其具有快速简便、选择性好、灵敏度高等优点,在临床医学、遗传工程、环境检测、食品安全监测和生物科学等领域有着重要的应用价值.简述了杂交型DNA电化学生物传感器的一般原理,对共价键结合法、自组装法、生物素-亲和素法、电聚合法以及吸附法等单链DNA的固定方法和DNA杂交信号的直接和间接电化学转换机制的近期研究进展进行了深入探讨,并对其在医疗检测和转基因植物检测等基因检测方面的最新应用和发展趋势进行了论述.     

AlGaN/GaN heterostructure field transistor for label-free detection of DNA hybridization

This paper demonstrates electrical detection of single strand deoxyribonucleic acid (ssDNA) conjugation by AlGaN/GaN hetero-structure field effect transistor (HFET) biological sensors. The probe ssDNA molecules are modified by thiol groups. The immobilization of probe molecules is achieved by S-Au bonding on a thin layer of gold film in the sensing area. The immobilization and hybridization process are firstly implemented on Si surfaces and checked by fluorescent and atomic force microscopy (AFM) imaging. The hybridization process is monitored on AlGaN/GaN HFETs. Time-dependent current change is observed when a matched ssDNA solution is applied, while no response is observed for a mismatched ssDNA sequence. The DNA hybridization process is dominated by the conjugation between matched ssDNA sequences in the first few tens of seconds. After that, the hybridization process is dominated by mass transfer processes and saturation of the immobilized probe ssDNA molecules.     

Covalent immobilization of oligoDNA on the surface of magnetic nanoparticles and surface-enhanced Raman scattering study

The DNA magnetic nanoparticles are potentially useful in isolating and purifying DNA or RNA, directing-target-medicines, the development of DNA biosensors and biochips. Surface functionalized magnetic nanoparticles with monodispersed shape and size were prepared by coating nano-sized γ-Fe2O3 with silica in reverse microemuision, and then thioi-compounds were immobilized onto the magnetic nanoparticles. After immobilizing oligoDNA modified with thioi-disuifide on the surface of the fictionalized magnetic nanoparticles, we obtained DNA-magnetic nanoparticles.The efficiency of the single-linking probes loading at the surfaces of magnetic nanoparticles was examined via hybridization experiment. Surface-enhanced Raman scattering methods were also effectively applied to observing the immobilization and hybridization processes mentioned above.The results demonstrated oligoDNA being availably connected to the surface of the magnetic nanoparticles.     

Surface modification of nanogold particles in DNA detection with quartz crystal microbalance

Nanogold particles in different sizes, from 5 to 60 nm, were utilized to modify the surface of the quartz crystal microbalance (QCM). It was found that the gold-particle size of the modified QCM affects both the amount of the immobilization of the probe on the surface of QCM and the hybridization rate of the target DNA. 20 nm was determined to be the optimal size for the surface modification and it can maximally increase the sensitivity of the DNA detection.