The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, St Lucia, QLD 4072, Australia.
Soft Matter. 2017 Nov 8;13(43):7953-7961. doi: 10.1039/c7sm01614j.
The interfacial properties of nanoscale materials have profound influence on biodistribution and stability as well as the effectiveness of sophisticated surface-encoded properties such as active targeting to cell surface receptors. Tailorable nanocarrier emulsions (TNEs) are a novel class of oil-in-water emulsions stabilised by molecularly-engineered biosurfactants that permit single-pot stepwise surface modification with related polypeptides that may be chemically conjugated or genetically fused to biofunctional moieties. We have probed the structure and function of poly(ethylene glycol) (PEG) used to decorate TNEs in this way. The molecular weight of PEG decorating TNEs has considerable impact on the ζ-potential of the emulsion particles, related to differential interfacial thickness of the PEG layer as determined by X-ray reflectometry. By co-modifying TNEs with an antibody fragment, we show that the molecular weight and density of PEG governs the competing parameters of accessibility of the targeting moiety and of shielding the interface from non-specific interactions with the environment. The fundamental understanding of the molecular details of the PEG layer that we present provides valuable insights into the structure-function relationship for soft nanomaterial interfaces. This work therefore paves the way for further rational design of TNEs and other nanocarriers that must interact with their environment in controlled and predictable ways.
纳米材料的界面性质对其生物分布和稳定性以及复杂表面编码性质的有效性有深远影响，如主动靶向细胞表面受体。可定制的纳米载体乳液（TNEs）是一类新型的水包油乳液，由经过分子工程设计的生物表面活性剂稳定，允许通过相关多肽进行单步逐步表面修饰，这些多肽可以通过化学偶联或基因融合到生物功能部分上。我们已经研究了用于以这种方式修饰 TNEs 的聚乙二醇（PEG）的结构和功能。PEG 修饰 TNEs 的分子量对乳液颗粒的 ζ-电位有很大影响，这与通过 X 射线反射测量法确定的 PEG 层的界面厚度有关。通过用抗体片段共同修饰 TNEs，我们表明 PEG 的分子量和密度决定了靶向部分的可及性和界面免受与环境的非特异性相互作用的屏蔽这两个竞争参数。我们提出的 PEG 层的分子细节的基本理解为软纳米材料界面的结构-功能关系提供了有价值的见解。因此，这项工作为进一步合理设计 TNEs 和其他必须以可控和可预测的方式与其环境相互作用的纳米载体铺平了道路。
