Adhesion force spectroscopy with nanostructured colloidal probes reveals nanotopography-dependent early mechanotransductive interactions at the cell membrane level.

Mechanosensing, the ability of cells to perceive and interpret the microenvironmental biophysical cues (such as the nanotopography), impacts strongly cellular behaviour through mechanotransductive processes and signalling. These events are predominantly mediated by integrins, the principal cellular adhesion receptors located at the cell/extracellular matrix (ECM) interface. Because of the typical piconewton force range and nanometre length scale of mechanotransductive interactions, achieving a detailed understanding of the spatiotemporal dynamics occurring at the cell/microenvironment interface is challenging; sophisticated interdisciplinary methodologies are required. Moreover, an accurate control over the nanotopographical features of the microenvironment is essential, in order to systematically investigate and precisely assess the influence of the different nanotopographical motifs on the mechanotransductive process. In this framework, we were able to study and quantify the impact of microenvironmental nanotopography on early cellular adhesion events by means of adhesion force spectroscopy based on innovative colloidal probes mimicking the nanotopography of natural ECMs. These probes provided the opportunity to detect nanotopography-specific modulations of the molecular clutch force loading dynamics and integrin clustering at the level of single binding events, in the critical time window of nascent adhesion formation. Following this approach, we found that the nanotopographical features are responsible for an excessive force loading in single adhesion sites after 20-60 s of interaction, causing a drop in the number of adhesion sites. However, by manganese treatment we demonstrated that the availability of activated integrins is a critical regulatory factor for these nanotopography-dependent dynamics.

Bottom-up engineering of the surface roughness of nanostructured cubic zirconia to control cell adhesion.

Nanostructured cubic zirconia is a strategic material for biomedical applications since it combines superior structural and optical properties with a nanoscale morphology able to control cell adhesion and proliferation. We produced nanostructured cubic zirconia thin films at room temperature by supersonic cluster beam deposition of nanoparticles produced in the gas phase. Precise control of film roughness at the nanoscale is obtained by operating in a ballistic deposition regime. This allows one to study the influence of nanoroughness on cell adhesion, while keeping the surface chemistry constant. We evaluated cell adhesion on nanostructured zirconia with an osteoblast-like cell line using confocal laser scanning microscopy for detailed morphological and cytoskeleton studies. We demonstrated that the organization of cytoskeleton and focal adhesion formation can be controlled by varying the evolution of surface nanoroughness.

[Endovascular treatment of pararenal aortic aneurysms]. / Il trattamento endovascolare degli aneurismi dell'aorta pararenale.

Endovascular procedures have emerged as an attractive alternative technique for the repair of abdominal aortic aneurysms with an increasing popularity and diffusion. Even if technology progresses are developing more and more efficient grafts and devices, at the moment the endovascular treatment is still not applicable to all patients. The most common reason for patient exclusion remains an unsuitable proximal implantation site. Endografts with suprarenal fixation were studied for solving the problem of the proximal neck but results seem to be not so encouraging. At the moment pararenal aortic aneurysms, involving ostia of renal or visceral arteries, are usually excluded from endovascular treatment. The solution could be a custom-made graft for each single patient, with fenestrations or branches for renal and visceral arteries. The first clinical use of a fenestrated graft was by Park in 1996 and some groups are now studying different kinds of grafts, both in experimental and clinical studies, which are opening attractive new possibilities. At present results are only preliminary but this would be the first step towards the potential substitution of the entire aorta through endovascular techniques.