Materials and Interfaces Department, Weizmann Institute of Science, Rehovot 76100, Israel.
Department of Physical and Theoretical Chemistry, Oxford University, Oxford OX1 3QZ, United Kingdom.
Sci Rep. 2017 Apr 6;7:45758. doi: 10.1038/srep45758.
Nanoparticles (NPs) which enter physiological fluids are rapidly coated by proteins, forming a so-called corona which may strongly modify their interaction with tissues and cells relative to the bare NPs. In this work the interactions between a living cell and a nano-object, and in particular the effect on this of the adsorption of serum proteins, are directly examined by measuring the forces arising as an Atomic Force Microscope tip (diameter 20 nm) - simulating a nano-object - approaches and contacts a cell. We find that the presence of a serum protein corona on the tip strongly modifies the interaction as indicated by pronounced increase in the indentation, hysteresis and work of adhesion compared to a bare tip. Classically one expects an AFM tip interacting with a cell surface to be repelled due to cell elastic distortion, offset by tip-cell adhesion, and indeed such a model fits the bare-tip/cell interaction, in agreement with earlier work. However, the force plots obtained with serum-modified tips are very different, indicating that the cell is much more compliant to the approaching tip. The insights obtained in this work may promote better design of NPs for drug delivery and other nano-medical applications.
纳米粒子（NPs）进入生理流体后会迅速被蛋白质覆盖，形成所谓的“冠”，这可能会强烈改变它们与组织和细胞的相互作用，与裸 NPs 相比。在这项工作中，通过测量作为原子力显微镜针尖（直径 20nm）-模拟纳米物体-接近和接触细胞时产生的力，直接研究了活细胞与纳米物体之间的相互作用，特别是吸附血清蛋白对这种相互作用的影响。我们发现，针尖上存在血清蛋白冠强烈改变了相互作用，表现为与裸针尖相比，压痕、滞后和粘附功显著增加。经典的观点认为，由于细胞弹性变形，与细胞表面相互作用的 AFM 针尖会受到排斥，这被针尖-细胞的粘附所抵消，事实上，这种模型与裸针尖/细胞相互作用相吻合，与早期的工作一致。然而，用血清修饰后的针尖获得的力图非常不同，这表明细胞对接近的针尖更具弹性。这项工作中获得的见解可能会促进更好地设计用于药物输送和其他纳米医学应用的 NPs。
