PROBING MECHANICAL INTERACTIONS IN CELLS AND THEIR MICROENVIRONMENT BY ATOMIC FORCE MICROSCOPY

Biological samples like cells and Extracellular matrices (ECMs) may be classified among the most challenging specimens, mainly due to their intrinsic complexity, which manifests itself at multiple levels, from the nano- to the microscale. Nevertheless, the relevance of an in-depth study of the biophysical properties and reciprocal interactions of cells and ECMs is undeniable, since the established evidence of a strong correlation between the latter, and the physiopathological state of tissues and organisms. In particular, in the last decades the mechanical phenotype of cells and tissues turned out to be an important biophysical marker of hidden and fine-tuned molecular processes. In this context, the Atomic Force Microscope (AFM) offers a strong support to standard biochemical techniques, mainly thanks to its great versatility, which allows on the one hand to map simultaneously the topography and diverse physico-chemical properties of the sample; on the other hand, it allows matching the typical physical dimensions of the system under study by a suitable choice of the probe. In the light of these considerations, the first goal of my PhD project has been the development of a comprehensive and quantitative protocol for the AFM-based topographic and mechanical imaging of living cells, ECMs, and tissues. This, in turn, has provided a solid background for the investigation of biologically relevant systems: the mechanisms at the basis of cell adhesion and migration processes; the interplay between cells and ECMs in the framework of colorectal carcinoma and inflammatory bowel disease progression; the quantitative characterization of the mechanotransductive events promoting the differentiation of neuron-like cells cultured on biomimetic nanostructured substrates, produced by means of Supersonic Cluster Beam Deposition. The results obtained can provide a significant progress towards the effective standardization of AFM-based mechanical characterization of soft and biological samples, with potential applications in the fields of clinical and regenerative medicine.