Hoffmann Stefan, Gorzelanny Christian, Moerschbacher Bruno, Goycoolea Francisco M
Institute of Plant Biology and Biotechnology (IBBP), Westfälische Wilhelms-Universität Münster, Schlossplatz 8, 48143 Münster, Germany.
Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
Nanomaterials (Basel). 2018 Oct 17;8(10):846. doi: 10.3390/nano8100846.
Sub-micron o/w emulsions coated with chitosan have been used for drug delivery, quorum sensing inhibition, and vaccine development. To study interactions with biological systems, nanocapsules have been fluorescently labelled in previous works, but it is often difficult to distinguish the released label from intact nanocapsules. In this study, we present advanced-labelling strategies based on Förster Resonance Energy Transfer (FRET) measurements for chitosan-coated nanocapsules and investigate their dissolution and degradation. We used FRET measurements of nanocapsules loaded with equimolar concentrations of two fluorescent dyes in their oily core and correlated them with dynamic light scattering (DLS) count rate measurement and absorbance measurements during their disintegration by dissolution. Using count rate measurements, we also investigated the enzymatic degradation of nanocapsules using pancreatin and how protein corona formation influences their degradation. Of note, nanocapsules dissolved in ethanol, while FRET decreased simultaneously with count rate, and absorbance was caused by nanocapsule turbidity, indicating increased distance between dye molecules after their release. Nanocapsules were degradable by pancreatin in a dose-dependent manner, and showed a delayed enzymatic degradation after protein corona formation. We present here novel labelling strategies for nanocapsules that allow us to judge their status and an in vitro method to study nanocapsule degradation and the influence of surface characteristics.
壳聚糖包被的亚微米油包水乳液已被用于药物递送、群体感应抑制和疫苗开发。为了研究与生物系统的相互作用，在先前的研究中已对纳米胶囊进行了荧光标记，但通常很难将释放的标记物与完整的纳米胶囊区分开来。在本研究中，我们提出了基于Förster共振能量转移（FRET）测量的壳聚糖包被纳米胶囊的先进标记策略，并研究了它们的溶解和降解情况。我们对油相中负载等摩尔浓度两种荧光染料的纳米胶囊进行了FRET测量，并将其与动态光散射（DLS）计数率测量以及溶解崩解过程中的吸光度测量相关联。利用计数率测量，我们还研究了胰蛋白酶对纳米胶囊的酶促降解以及蛋白质冠形成如何影响其降解。值得注意的是，纳米胶囊溶解于乙醇中时，FRET随计数率同时降低，吸光度由纳米胶囊的浊度引起，表明染料分子释放后其间距增大。纳米胶囊可被胰蛋白酶以剂量依赖的方式降解，并且在形成蛋白质冠后显示出酶促降解延迟。我们在此展示了用于纳米胶囊的新型标记策略，该策略使我们能够判断其状态，并提供了一种体外方法来研究纳米胶囊的降解以及表面特性的影响。
