Panzetta Valeria, Guarnieri Daniela, Paciello Antonio, Della Sala Francesca, Muscetti Ornella, Raiola Luca, Netti Paolo, Fusco Sabato
Center for Advanced Biomaterials for Health Care IIT@CRIB, Istituto Italiano di Tecnologia, L.go Barsanti e Matteucci 53, Naples 80125, Italy.
Interdisciplinary Research Centre on Biomaterials, CRIB and Department of Chemical, Materials & Industrial Production Engineering, University of Naples Federico II, Naples 80125, Italy.
ACS Biomater Sci Eng. 2017 Aug 14;3(8):1586-1594. doi: 10.1021/acsbiomaterials.7b00018. Epub 2017 Jun 22.
It is possible to create sophisticated and target-specific devices for nanomedicine thanks to technological advances in the engineering of nanomaterials. When on target, these nanocarriers often have to be internalized by cells in order to accomplish their diagnostic or therapeutic function. Therefore, the control of such uptake mechanism by active targeting strategy has today become the new challenge in nanoparticle designing. It is also well-known that cells are able to sense and respond to the local physical environment and that the substrate stiffness, and not only the nanoparticle design, influences the cellular internalization mechanisms. In this frame, our work reports on the cyclic relationship among substrate stiffness, cell cytoskeleton assembly and internalization mechanism. Nanoparticles uptake has been investigated in terms of the mechanics of cell environment, the resulting cytoskeleton activity and the opportunity of activate molecular specific molecular pathways during the internalization process. To this aim, the surface of 100 nm polystyrene nanoparticles was decorated with a tripeptide (RGD and a scrambled version as a control), which was able to activate an internalization pathway directly correlated to the dynamics of the cell cytoskeleton, in turn, directly correlated to the elastic modulus of the substrates. We found that the substrate stiffness modulates the uptake of nanoparticles by regulating structural parameters of bEnd.3 cells as spreading, volume, focal adhesion, and mechanics. In fact, the nanoparticles were internalized in larger amounts both when decorated with RGD, which activated an internalization pathway directly correlated to the cell cytoskeleton, and when cells resided on stiffer material that, in turn, promoted the formation of a more structured cytoskeleton. This evidence indicates the directive role of the mechanical environment on cellular uptake of nanoparticles, contributing new insights to the rational design and development of novel nanocarrier systems.
由于纳米材料工程技术的进步，有可能为纳米医学制造复杂且具有靶向特异性的设备。当纳米载体到达靶点时，为了实现其诊断或治疗功能，它们通常必须被细胞内化。因此，通过主动靶向策略控制这种摄取机制已成为纳米颗粒设计中的新挑战。众所周知，细胞能够感知并响应局部物理环境，并且底物硬度不仅会影响纳米颗粒的设计，还会影响细胞内化机制。在此背景下，我们的工作报道了底物硬度、细胞细胞骨架组装和内化机制之间的循环关系。我们从细胞环境力学、由此产生的细胞骨架活性以及内化过程中激活分子特定分子途径的机会等方面研究了纳米颗粒的摄取。为此，在100 nm聚苯乙烯纳米颗粒的表面修饰了一种三肽（RGD及其作为对照的乱序版本），该三肽能够激活与细胞细胞骨架动力学直接相关的内化途径，进而与底物的弹性模量直接相关。我们发现，底物硬度通过调节bEnd.3细胞的结构参数（如铺展、体积、粘着斑和力学）来调节纳米颗粒的摄取。事实上，当用RGD修饰纳米颗粒时，纳米颗粒的内化量更大，RGD激活了与细胞细胞骨架直接相关的内化途径；当细胞位于更硬的材料上时，纳米颗粒的内化量也更大，更硬的材料反过来促进了更结构化细胞骨架的形成。这一证据表明了机械环境在细胞摄取纳米颗粒中的指导作用，为新型纳米载体系统的合理设计和开发提供了新的见解。
