Department of Micro- and Nanotechnology, Technical University of Denmark (DTU), Ørsteds Plads Bygning 345Ø, 2800 Kgs, Kongens Lyngby, Denmark.
Department of Engineering and Architecture, University of Trieste, Building B, via Valerio 6, I-34127, Trieste, Italy.
Pharm Res. 2018 Jul 2;35(9):171. doi: 10.1007/s11095-018-2427-0.
This paper is based on the characterization of the rheological and Low Field NMR (LF-NMR) properties of an interpenetrated hydrogel made up by poly(N-vinyl-2-pyrrolidone) and sodium alginate. The final aim is to use the hydrogel as a delivery matrix for liposomes, widely used tools in the drug delivery field.
Rheology, LF-NMR, TEM, cryo-TEM, confocal laser scanning microscopy and release test were employed to characterize the interpenetrated hydrogel. Different theoretical approaches such as Flory, Chui, Scherer and Schurz theories were used to interpret the experimental results.
We found that the crosslinking mechanisms of the two polymers produced an anti-synergistic effect on the final mechanical properties of the interpenetrated hydrogel. Instead of creating a continuous network, alginate formed isolated, cross-linked, clusters embedded in a continuous network of poly(N-vinyl-2-pyrrolidone). Additionally, gel structure significantly influenced liposome delivery.
The rheological and LF-NMR characterization were confirmed and supported by the independent techniques TEM, cryo-TEM and release tests Thus, our findings reiterate the potentiality of both rheology and LF-NMR for the characterisation of soft materials such as interpenetrated polymeric networks.
本文基于互穿水凝胶的流变性和低场核磁共振（LF-NMR）特性的表征，该水凝胶由聚（N-乙烯基-2-吡咯烷酮）和海藻酸钠组成。最终目的是将水凝胶用作脂质体的递送基质，脂质体是药物递送领域中广泛使用的工具。
采用流变学、LF-NMR、TEM、冷冻 TEM、共聚焦激光扫描显微镜和释放试验对互穿水凝胶进行了表征。采用 Flory、Chui、Scherer 和 Schurz 等不同理论方法来解释实验结果。
我们发现两种聚合物的交联机制对互穿水凝胶的最终力学性能产生了抗协同效应。海藻酸盐并未形成连续的网络，而是形成了孤立的、交联的簇，嵌入在聚（N-乙烯基-2-吡咯烷酮）的连续网络中。此外，凝胶结构对脂质体的递送有显著影响。
流变学和 LF-NMR 的特征通过 TEM、冷冻 TEM 和释放试验等独立技术得到了证实和支持。因此，我们的研究结果重申了流变学和 LF-NMR 用于表征互穿聚合物网络等软物质的潜力。
