Department of Engineering, Aarhus University, Aarhus, Denmark ; College of Life Science and Technology, Beijing University of Chemical Technology (BUCT), Beijing, China.
PLoS One. 2013 Sep 12;8(9):e73891. doi: 10.1371/journal.pone.0073891. eCollection 2013.
Physical stability during storage and against processing such as dehyration/rehydration are the cornerstone in designing delivery vehicles. In this work, mono-, di- and tri-saccharides were enzymatically conjugated to phosphatidyl group through a facile approach namely phospholipase D (PLD) mediated transphosphatidylation in a biphasic reaction system. The purified products were structurally identified and the connectivities of carbohydrate to phosphatidyl moiety precisely mapped by (1)H, (31)P, (13)C NMR pulse sequences and LC-ESI-FTMS. The synthetic phosphatidyl saccharides were employed as the sole biomimetic component for preparation of nanoliposomes. It was found that the critical micelle concentration (CMC) of phosphatidyl saccharides increases as more bulky sugar moiety (mono- to tri-) is introduced. Phosphatidyl di-saccharide had the largest membrane curvature. In comparison to the zwitterionic phosphatidylcholine liposome, all phosphatidyl saccharides liposomes are anionic and demonstrated significantly enhanced stability during storage. According to the confocal laser scan microscopy (CLSM) and atom force microscopy (AFM) analyses, the nanoliposomes formed by the synthetic phosphatidyl saccharides also show excellent stability against dehydration/rehydration process in which most of the liposomal structures remained intact. The abundance hydroxyl groups in the saccharide moieties might provide sufficient H-bondings for stabilization. This work demonstrated the synthesized phosphatidyl saccharides are capable of functioning as enzymatically liable materials which can form stable nanoliposomes without addition of stabilizing excipients.
在储存过程中和脱水/复水等处理过程中的物理稳定性是设计输送载体的基石。在这项工作中，单糖、二糖和三糖通过一种简单的方法通过磷脂酶 D (PLD) 介导的双相反应系统与磷酯基团酶促连接。通过 (1)H、(31)P、(13)C NMR 脉冲序列和 LC-ESI-FTMS 对纯化产物进行了结构鉴定，并精确绘制了碳水化合物与磷酯部分的连接性。合成的磷脂糖被用作制备纳米脂质体的唯一仿生成分。结果发现，随着更大体积糖部分（单糖至三糖）的引入，磷脂糖的临界胶束浓度（CMC）增加。磷脂二糖具有最大的膜曲率。与两性离子磷脂酰胆碱脂质体相比，所有磷脂糖脂质体均为阴离子，在储存过程中表现出显著增强的稳定性。根据共焦激光扫描显微镜 (CLSM) 和原子力显微镜 (AFM) 分析，由合成的磷脂糖形成的纳米脂质体在脱水/复水过程中也表现出优异的稳定性，其中大多数脂质体结构保持完整。糖部分中丰富的羟基可能为稳定提供足够的氢键。这项工作表明，合成的磷脂糖能够作为酶活性物质，在不添加稳定赋形剂的情况下形成稳定的纳米脂质体。
