Wei Yushuang, Chen Haibo, Li Yue-Xuan, He Kejie, Yang Kai, Pang Hong-Bo
Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55455, United States.
Center for Soft Condensed Matter Physics and Interdisciplinary Research & School of Physical Science and Technology, Soochow University, Suzhou 215006, China.
ACS Nano. 2022 Apr 26;16(4):5885-5897. doi: 10.1021/acsnano.1c11068. Epub 2022 Mar 18.
Cell entry is one of the common prerequisites for nanomaterial applications. Despite extensive studies on a homogeneous group of nanoparticles (NPs), fewer studies have been performed when two or more types of NPs were coadministrated. We previously described a synergistic cell entry process for two heterogeneous groups of NPs, where NPs functionalized with TAT (transactivator of transcription) peptide (T-NPs) stimulate the cellular uptake of coadministered unfunctionalized NPs (bystander NPs, B-NPs). Here, we show that the synergistic cell entry of NPs is driven by free energy decline and depends on B-NP sizes. Simulations showed that when separately placed initially, two NPs first move toward each other instead of initiating cell entry individually. Only T-NP invokes an inward bending of membrane mimicking endocytosis, which attracts the nearby NPs into the same "vesicle". A two-phase free energy decline of the entire system occurred as two NPs get closer until contact, which is likely the thermodynamic driver for synergistic NP coentry. Experimentally, we found that T-NPs increase the apparent affinity of B-NPs to plasma membrane, suggesting that T-NPs help B-NPs "trapped" in the endocytic vesicles. Next, we varied the sizes of B-NPs and found that bystander activity peaks around 50 nm. Simulations also showed that the size of B-NPs influences the free energy decline, and thus the tendency and dynamics of NP coentry. These efforts provide a system to further understand the synergistic cell entry among individual NPs or multiple NP types on a biophysical basis and shed light on the future design of nanostructures for intracellular delivery.
细胞摄取是纳米材料应用的常见前提条件之一。尽管对同类纳米颗粒（NPs）进行了广泛研究，但当两种或更多种类型的 NPs 共同给药时，相关研究较少。我们之前描述了两种异质 NPs 群体的协同细胞摄取过程，其中用 TAT（转录激活因子）肽功能化的 NPs（T-NPs）刺激共同给药的未功能化 NPs（旁观者 NPs，B-NPs）的细胞摄取。在这里，我们表明 NPs 的协同细胞摄取是由自由能下降驱动的，并且取决于 B-NP 的大小。模拟表明，当初始分别放置时，两种 NPs 首先相互靠近，而不是单独启动细胞摄取。只有 T-NP 引发模仿内吞作用的膜向内弯曲，这将附近的 NPs 吸引到同一个“囊泡”中。随着两种 NPs 靠近直至接触，整个系统发生两阶段自由能下降，这可能是 NPs 协同进入的热力学驱动力。实验上，我们发现 T-NPs 增加了 B-NPs 对质膜的表观亲和力，表明 T-NPs 有助于将 B-NPs“捕获”在内吞囊泡中。接下来，我们改变了 B-NPs 的大小，发现旁观者活性在 50 nm 左右达到峰值。模拟还表明，B-NPs 的大小影响自由能下降，从而影响 NPs 共同进入的趋势和动力学。这些工作提供了一个系统，以在生物物理基础上进一步理解单个 NPs 或多种 NP 类型之间的协同细胞摄取，并为细胞内递送的纳米结构未来设计提供启示。
