Departamento de Física Aplicada, Universidad de Granada, Campus Fuentenueva S/N, 18071 Granada, Spain.
Instituto Carlos I de Física Teórica y Computacional, Facultad de Ciencias, Universidad de Granada, Campus Fuentenueva S/N, 18071 Granada, Spain.
ACS Nano. 2020 Nov 24;14(11):15227-15240. doi: 10.1021/acsnano.0c05480. Epub 2020 Nov 11.
We study the nonequilibrium diffusive release of electroneutral molecular cargo encapsulated inside hollow hydrogel nanoparticles. We propose a theoretical model that includes osmotic, steric, and short-range polymer-cargo attractions to determine the effective cargo-hydrogel interaction, *, and the effective diffusion coefficient of the cargo inside the polymer network, *. Using dynamical density functional theory (DDFT), we investigate the scaling of the characteristic release time, τ, with the key parameters involved in the process, namely, , , and the swelling ratio. This effort represents a full study of the problem, covering a broad range of cargo sizes and providing predictions for repulsive and attractive polymer shells. Our calculations show that the release time through repulsive polymer networks scales with e/ for β ≫ 1. In this case, the cargo molecules are excluded from the shell of the hydrogel. For attractive shells, the polymer retains the cargo molecules on its internal surface and its interior, and the release time grows exponentially with the attraction strength. The DDFT calculations are compared to an analytical model for the mean first passage time, which provides an excellent quantitative description of the kinetics for both repulsive and attractive shells without fitting parameters. Finally, we apply the method to reproduce experimental results on the release of paclitaxel from hollow poly(4-vinylpyridine) nanoparticles and find that the slow release of the drug can be explained in terms of the strong binding attraction between the drug and the polymer.
我们研究了封装在中空水凝胶纳米粒子内部的电中性分子货物的非平衡扩散释放。我们提出了一个理论模型，该模型包括渗透压、空间位阻和短程聚合物-货物吸引力，以确定货物与水凝胶的有效相互作用和货物在聚合物网络中的有效扩散系数。我们使用动态密度泛函理论（DDFT）研究了特征释放时间τ与过程中涉及的关键参数（即*、*和溶胀比）的标度关系。这项工作代表了对该问题的全面研究，涵盖了广泛的货物尺寸，并对排斥和吸引聚合物壳进行了预测。我们的计算表明，通过排斥聚合物网络的释放时间与 e/成正比，对于β≫1。在这种情况下，货物分子被排斥在水凝胶的壳外。对于有吸引力的外壳，聚合物将货物分子保留在其内部表面和内部，释放时间随吸引力强度呈指数增长。DDFT 计算与平均首次通过时间的解析模型进行了比较，该模型无需拟合参数即可对排斥和吸引外壳的动力学提供极好的定量描述。最后，我们应用该方法重现了紫杉醇从中空聚（4-乙烯基吡啶）纳米粒子中释放的实验结果，并发现药物的缓慢释放可以用药物与聚合物之间的强结合吸引力来解释。
