Papers by Author: Francesca Boccafoschi

Abstract: It is well-known that cellular behavior can be guided by chemical signals and physical interactions at the cell-substrate interface. The patterns that cells encounter in their natural environment include nanometer-to-micrometer-sized topographies comprising extracellular matrix, proteins, and adjacent cells. Whether cells transduce substrate rigidity at the microscopic scale (for example, sensing the rigidity between adhesion sites) or the nanoscopic scale remains an open question. Here we report that micromolded elastomeric micropost arrays can decouple substrate rigidity from adhesive and surface properties. Arrays of poly (dimethylsiloxane) (PDMS) microposts from microfabricated silicon masters have been fabricated. To control substrate rigidity they present the same post heights but different surface area and spacing between posts. The main advantage of micropost arrays over other surface modification solutions (i.e. hydrogels) is that measured subcellular traction forces could be attributed directly to focal adhesions. This would allow to map traction forces to individual focal adhesions and spatially quantify subcellular distributions of focal-adhesion area, traction force and focal-adhesion stress. Moreover, different adhesion intracellular pathways could be used by the cells to differentiate toward a proliferative or a contractile cellular phenotype, for instance. This particular application is advantageous for vascular tissue engineering applications, where mimicking as close as possible the vessels dynamics should be a step forward in this research field.

Abstract: Materials in contact with tissue and biological fluids affect cell reaction that could eventually lead to clinical complications (i.e. thrombosis, restenosis). Improving the biological performances of the materials used for biomedical applications is the main goal of this study. In particular, cardiovascular devices require excellent haemo- and biocompatibility properties. PTFE is currently the main material used for vascular prostheses. After long contact periods with blood, clinical complications leading to thrombosis and restenosis are often reported. Improving the haematological performances of PTFE could significantly increase its life-time and decrease long-term complications. However, inadequately engineered surfaces could trigger the coagulation cascade with the formation of a clot, the first step towards a thrombosis. Plasma carbon-based coatings with varying nitrogen contents deposited on PTFE have been studied as promising coating to improve the haematological performances of PTFE implants. In this work, several techniques were applied to study the viscoelastic properties of blood after contact with virgin and treated PTFE as well as the presence and the clot morphology eventually formed onto the surfaces. The chemical composition of the surfaces was analysed with XPS and FTIR.

Abstract: Materials in contact with tissue and biological fluids affect cell reaction that could eventually lead to clinical complications (i.e. thrombosis, restenosis). Improving the biological performances of the materials used for biomedical applications is the main goal of this study. In particular, cardiovascular devices require excellent haemo- and biocompatibility properties. PTFE is currently the main material used for vascular prostheses. After long contact periods with blood, clinical complications leading to thrombosis and restenosis are often reported. Improving the haematological performances of PTFE could significantly increase its life-time and decrease long-term complications. However, inadequately engineered surfaces could trigger the coagulation cascade with the formation of a clot, the first step towards a thrombosis. Plasma carbon-based coatings with varying nitrogen contents deposited on PTFE have been studied as promising coating to improve the haematological performances of PTFE implants. In this work, several techniques were applied to study the viscoelastic properties of blood after contact with virgin and treated PTFE as well as the presence and the clot morphology eventually formed onto the surfaces. The chemical composition of the surfaces was analysed with XPS and FTIR.