Immobilization of biomolecules on the surface of inorganic nanoparticles for biomedical applications

Various inorganic nanoparticles have been used for drug delivery, magnetic resonance and fluorescence imaging, and cell targeting owing to their unique properties, such as large surface area and efficient contrasting effect. In this review, we focus on the surface functionalization of inorganic nanoparticles via immobilization of biomolecules and the corresponding surface interactions with biocomponents. Applications of surface-modified inorganic nanoparticles in biomedical fields are also outlined.     

Phosphatase active cross-flow microfiltration poly(vinylidene difluoride) bioreactor

Alkaline phosphatase from human placenta has been chemically immobilized on a hydrophilic cross-flow microfiltration membrane made from poly(vinylidene difluoride) (PVDF) derivatized with 1,1′-carbonyldiimidazole. The physicochemical characterization of the immobilized biocatalyst paid special attention to the irreversibility of the bonding of the enzyme to the support, the effects of pH, temperature and ionic strength on this activity, the existence of limitations of internal and external diffusion for H⁺, substrate and/or products, and the kinetic behavior (intrinsic and/or effective) of the immobilized enzyme. With respect to enzyme stability, patterns of hysteresis or memory are proposed, to account for a catalytic activity affected by previous experimental events and situations. The intrinsic kinetic behaviour, rate versus substrate concentration in the absence of diffusional restrictions, was analysed graphically and numerically (by non-linear regression and by utilizing the F statistical test for model discrimination), postulating a minimum rational rate equation of 2:2 degree in substrate concentration. In concordance, a mechanistic kinetic scheme for the catalytic enzyme action has been postulated.     

Covalently Immobilized Regenerable Immunoaffinity Layer with Orientation-Controlled Antibodies Based on Z-Domain Autodisplay

A regenerable immunoaffinity layer comprising covalently immobilized orientation-controlled antibodies was developed for use in a surface plasmon resonance (SPR) biosensor. For antibody orientation control, antibody-binding Z-domain-autodisplaying Escherichia coli (E. coli) cells and their outer membrane (OM) were utilized, and a disuccinimidyl crosslinker was employed for covalent antibody binding. To fabricate the regenerable immunoaffinity layer, capture antibodies were bound to autodisplayed Z-domains, and then treated with the crosslinker for chemical fixation to the Z-domains. Various crosslinkers, namely disuccinimidyl glutarate (DSG), disuccinimidyl suberate (DSS) and poly (ethylene glycol)-ylated bis (sulfosuccinimidyl)suberate (BS(PEG)₅), were evaluated, and DSS at a concentration of 500 μM was confirmed to be optimal. The E. coli-cell-based regenerable HRP immunoassay was evaluated employing three sequential HRP treatment and regeneration steps. Then, the Oms of E. coli cells were isolated and layered on a microplate and regenerable OM-based HRP immunoassaying was evaluated. Five HRP immunoassays with four regeneration steps were found to be feasible. This regenerable, covalently immobilized, orientation-controlled OM-based immunoaffinity layer was applied to an SPR biosensor, which was capable of quantifying C-reactive protein (CRP). Five regeneration cycles were repeated using the demonstrated immunoaffinity layer with a signal difference of <10%.     

天然番茄红素提取方法的实验研究

本文以新疆地产番茄酱为原料,研究了浸提温度、液料比、时间、浸提次数以及搅拌和酶处理等因素对番茄红素提取效果的影响,经研究确定了番茄红素的最佳提取条件为:以乙酸乙酯为溶剂,浸提温度为45℃,液料比为3﹕1,时间为35min,浸提次数为3次,若结合搅拌及酶处理,可达到较好的浸提效果.     

微生物甾体C11羟化反应的研究现状

羟化反应是甾体微生物转化反应中最重要的反应.介绍了甾体C11羟化的反应机理,并从增加底物溶解性,改善细胞通透性及新型转化系统等方面对微生物C11羟化的新工艺和新技术进行了综述,概述了近五年以来甾体C11羟化的研究现状.在甾体新型转化工艺方面,着重介绍了双液相体系、固定化技术、静息细胞法、多菌协同转化等技术.     

微生物固定法降解含油污水的研究进展

随着微生物固定化技术的发展,越来越多的研究成果应用于环境治理领域。固定化技术在废水生物治理领域中具有独特的优势和巨大的潜力。本文主要介绍了吸附法和包埋法这两种固定化方法载体的选择和制备方法,探讨了固定化技术对微生物生理特性的影响,综述了固定化技术在修复石油污染方面的应用,总结了固定化微生物技术在实际应用中存在的不足。     

酶法生产高浓度固体低聚果糖

介绍了近年来我国低聚果糖生产与应用的情况,提出的新工艺生产的高浓度固体低聚果糖,市场前景十分看好,具有极大的发展潜力。     

有机相中壳聚糖-海藻酸固定化脂酶的特性

研究了壳聚糖 海藻酸固定化脂酶在有机相反应中的稳定性与活性。考察了凝胶时间、壳聚糖浓度及壳聚糖分子质量对固定化脂酶包埋率与活性的影响 ,确定了适宜 pH值与批反应时间。同时讨论了溶剂极性和操作时间对固定化酶稳定性的影响。测定了固定化脂酶水解橄榄油反应的动力学参数。结果表明 ,壳聚糖 海藻酸聚电解质膜可提高固定化酶的包埋率与稳定性     

生物工程学和发酵技术

生物工程是应用生物有机体,生物系统或生物过程来制造工业产品的学科。生物工程在应用微生物方面有很悠久的历史。例如酿酒,发酵乳制品奶酪、酸乳等。目前又在发酵罐设计,发酵工艺,酶技术及遗传工程方面具有令人振奋的进展。生物工程学着重微生物学,生物化学和化学工程的结合,并直接付之实用。本综述主要介绍生物工程中几个同发酵有关的内容,即:微生物技术、酶技术及发酵枝术。     

光化学固定法表面改性医用高分子材料研究进展

综述了光化学固定法表面改性医用高分子材料方面的研究进展,介绍了光化学固定法的原理和优点。