As the gold standard polymer for drug delivery system, polyethylene glycol (PEG) has excellent biocompatibility. It's reported that the low nonspecific interactions between PEG and body contribute to its biocompatibility. However, here we discover dynamic biological interactions exist between PEG and cells on the molecular level. PEG (2 kD) can induce metabolism modulations and survival autophagy by creating an intracellular hypoxic environment, which act as cellular survival strategies in response to the hypoxia. In the cellular adaption process during hypoxia, PEG-treated cells decrease energy consumption by reducing cell growth rate, increase energy supply by amino acid catabolism in a short period, and survival autophagy over a relatively long period, to keep energy homeostasis and survival. Our research provides molecular insights for understanding the mechanism underlying the excellent biocompatibility of PEG, which will be of fundamental importance for further related studies on other polymers and development of polymeric materials with improved characteristics.

中文翻译：

---

聚乙二醇与细胞之间生物相互作用的分子见解

作为药物输送系统的金标准聚合物，聚乙二醇（PEG）具有出色的生物相容性。据报道，PEG与人体之间的低非特异性相互作用有助于其生物相容性。但是，在这里我们发现在分子水平上PEG与细胞之间存在动态的生物相互作用。PEG（2 kD）可以通过创建细胞内缺氧环境来诱导代谢调节和生存自噬，细胞内缺氧环境可以作为细胞对缺氧的生存策略。在缺氧期间的细胞适应过程中，经过PEG处理的细胞可通过降低细胞生长速率来减少能量消耗，通过氨基酸分解代谢在短期内增加能量供应，并在相对较长的时间内存活自噬，以保持能量稳态和存活。