Surface enhanced Raman spectroscopy measurements of MCF7 cells adhesion in confined micro-environments

•In this work, we fabricated regular arrays of cylindrical micro-pillars, then we modified the upper surface of those pillars to include random clusters of silver nano-grains where the average size of the grains is 50 nm and the standard deviation is maintained below 1/10 the dimension of the silver particles.•We analysed the interaction of MCF-7 (breast cancer) cells with similar substrates to reveal the mechanisms of cell adhesion in a micro-environment as that provided by a micro to nano-structured/super-hydrophobic design.•In doing so, we utilized optical methods including Scanning Electron Microscopy (SEM) techniques, and Surface Enhanced Raman Spectroscopy (SERS).

Undoubtedly cells can perceive the external environment, not only from a biochemical point of view with the related signalling pathways, but also from a physical and topographical perspective. In this sense controlled three dimensional micro-structures as well as patterns at the nano-scale can affect and guide the cell evolution and proliferation, due to the fact that the surrounding environment is no longer isotropic (like the flat surfaces of standard cell culturing) but possesses well defined symmetries and anisotropies. In this work regular arrays of silicon micro-pillars with hexagonal arrangement are used as culturing substrates for MCF-7 breast cancer cells. The characteristic size and spacing of the pillars are tens of microns, comparable with MCF-7 cell dimensions and then well suited to induce acceptable external stimuli. It is shown that these cells strongly modify their morphology for adapting themselves to the micro-structured landscape, by means of protrusions from the main body of the cell. Scanning electron microscopy along with both Raman micro-spectroscopy and surface enhanced Raman spectroscopy are used for topographical and biochemical studies of the new cell arrangement. We have revealed that single MCF-7 cells exploit their capability to produce invadopodia, usually generated to invade the neighboring tissue in metastatic activity, for spanning and growing across separate pillars.