The cell envelope of Gram-negative bacteria is a formidable biological barrier, inhibiting the action of antibiotics by impeding their permeation into the intracellular environment. In-depth understanding of permeation through this barrier remains a challenge, despite its critical role in antibiotic activity. We therefore designed a divisible in vitro permeation model of the Gram-negative bacterial cell envelope, mimicking its three essential structural elements, the inner membrane and the periplasmic space as well as the outer membrane, on a Transwell setup. The model was characterized by contemporary imaging techniques and employed to generate reproducible quantitative and time-resolved permeation data for various fluorescent probes and anti-infective molecules of different structure and physicochemical properties. For a set of three fluorescent probes, the permeation through the overall membrane model was found to correlate with in bacterio permeation. Even more interestingly, for a set of six Pseudomonas quorum sensing inhibitors, such permeability data were found to be predictive for their corresponding in bacterio activities. Further exploration of the capabilities of the overall model yielded a correlation between the permeability of porin-independent antibiotics and published in bacterio accumulation data; a promising ability to provide structure-permeability information was also demonstrated. Such a model may therefore constitute a valuable tool for the development of novel anti-infective drugs.

中文翻译：

---

革兰氏阴性细菌细胞包膜的体外模型，用于研究抗感染渗透动力学

革兰氏阴性细菌的细胞被膜是强大的生物屏障，可通过阻止其渗透进入细胞内环境来抑制抗生素的作用。尽管它在抗生素活性中起着至关重要的作用，但对通过这种屏障的渗透的深入了解仍然是一个挑战。因此，我们设计了可分割的体外革兰氏阴性细菌细胞包膜的渗透模型，在Transwell装置上模仿其三个基本结构元素，即内膜和周质空间以及外膜。该模型通过当代成像技术进行表征，并用于生成可重现的定量和时间分辨的渗透数据，用于各种荧光探针和具有不同结构和物理化学性质的抗感染分子。对于一组三个荧光探针，发现通过整个膜模型的渗透与细菌渗透相关。更有趣的是，对于一组六种假单胞菌群体感应抑制剂，发现此类渗透性数据可预测其相应的在细菌活动中。对整体模型功能的进一步探索产生了与孔蛋白无关的抗生素的渗透性与细菌积累数据中公布的相关性。还提供了提供结构渗透性信息的有前途的能力。因此，这样的模型可以构成开发新型抗感染药的有价值的工具。