Vamvakaki Vicky, Fournier Didier, Chaniotakis Nikos A
Laboratory of Analytical Chemistry, Department of Chemistry, Knossou Avenue, University of Crete, 71409 Iraklion, Crete, Greece.
Biosens Bioelectron. 2005 Aug 15;21(2):384-8. doi: 10.1016/j.bios.2004.10.028. Epub 2004 Dec 8.
The encapsulation of enzymes in microenvironments and especially in liposomes, has proven to greatly improve enzyme stabilization against unfolding, denaturation and dilution effects. Combining this stabilization effect, with the fact that liposomes are optically translucent, we have designed nano-sized spherical biosensors. In this work liposome-based biosensors are prepared by encapsulating the enzyme acetylcholinesterase (AChE) in L-a phosphatidylcholine liposomes resulting in spherical optical biosensors with an average diameter of 300+/-4 nm. Porins are embedded into the lipid membrane, allowing for the free substrate transport, but not that of the enzyme due to size limitations. The enzyme activity within the liposome is monitored using pyranine, a fluorescent pH indicator. The response of the liposome biosensor to the substrate acetylthiocholine chloride is relatively fast and reproducible, while the system is stable as has been shown by immobilization within sol-gel.
事实证明，将酶包裹在微环境中，尤其是脂质体中，能极大地提高酶的稳定性，使其免受展开、变性和稀释效应的影响。结合这种稳定效应以及脂质体具有光学半透明性这一事实，我们设计了纳米级球形生物传感器。在这项工作中，通过将乙酰胆碱酯酶（AChE）包裹在L-α磷脂酰胆碱脂质体中来制备基于脂质体的生物传感器，从而得到平均直径为300±4 nm的球形光学生物传感器。孔蛋白嵌入脂质膜中，允许底物自由运输，但由于尺寸限制，酶无法通过。脂质体内的酶活性使用荧光pH指示剂吡喃荧光素进行监测。脂质体生物传感器对底物氯化乙酰硫代胆碱的响应相对较快且可重复，同时正如通过固定在溶胶 - 凝胶中所显示的那样，该系统是稳定的。
