Nano- and micro-pillars for the control and regulation of cell migration and cell differentiation – Pillarcell

Nature does nothing uselessly (Aristotle: I.1253a8). This is also true for our human body, although it is highly complex and built up by highly synchronized sub-systems and a huge number of individual cells. When a body tissue or cells are placed in a dish, a flask or a multi-well plate, they undergo substantial changes of the cellular microenvironment, including extracellular matrix, soluble factors and cell-cell contacts. Such changes should have important consequences on the performance of cell-based assays, tissue engineering and regenerative medicine. Although a huge amount of research work has been done to improve the in-vitro culture conditions, it is still far way to approach the real in-vivo cellular microenvironments. One of the reasons is the lack of general platforms which allow high precision regulation of cellular microenvironments. Microengineering techniques are now widely used to fabricate surface texted culture substrates or synthetic extracellular matrix on one hand, and microfluidic devices for dynamic control of soluble factors on another hand. In this project, we propose a systematic investigation of cell migration and differentiation on patterned micro and nanopillars arrays, with or without integration into microfluidic devices. By changing the geometrical parameters of the pillars, we will particularly focus on the role of substrate stiffness cell migration and differentiation.
Previously, the most of investigations in this field were done with over simplified pattern design and fabrication. For example, micropillars of large diameters were produced using elastomer such as PDMS, which are suited for the cell force measurement but not for the control of cell migration and related applications. In this project, we plan to fabricate pillars with much small diameters, down to 100 nanometers, in order to cover a large range of pillar diameters which are required for controlled cell migration studies. We will also produce oblique pillars for directed cell migration under different assay configurations. Furthermore, we will design and generate a variety of pillar arrays varying in pillar diameter, spacing and height, in order to create stiffness gradients for durotaxis studies. Finally, we will propose a two-level patterning approach to create quasi three-dimensional features in order to achieve a new freedom in designing synthetic cellular microenvironment. Each type of the pillars will be evaluated by cell migration recordings. After optimization, the pillar arrays will be integrated into microfluidic devices to perform the same experiment under microflow conditions at a higher throughput. The final gold of this project is to assess the market potential of the proposed assays. Therefore, we propose a multidisciplinary consortium composed by three academic research teams (one from ENS specialized in nanofabrication technologies for cell biology, one from Curie Institute specialized in cell polarity and migration on patterned surface, and another from the University of Paris-Diderot (Institut Jacques Monod) specialized in biophysics of cell-based assays) and a start-up company (Elvesys) specialized in microfluidic instrumentation. Although our demonstration example will be done with micro and nanopillars, other types of patterns can also be produced in a similar manner. The fabricated samples can also be useful for other types of cell-based assays, including adhesion, proliferation, differentiation, and apoptosis etc. As the fabrication technology we proposed can be used for large scale manufacturing, it will be easy to convert our prototype devices into industrial production. To this end, we anticipate a number of clinic applications of such products including tissue engineering, wound healing, etc.