2, University of Ottawa, Ottawa, Ontario, Canada
In the quest for the next generation of functional biomaterials, researchers have sought inspiration from nature by developing better performing bio-derived materials (e.g. collagen, keratin, chitosan), reproducing naturally occurring micro and nanostructures (e.g. gecko feet fibrils, nanoporosity of collagen-apatite interfaces in bone) and devising strategies that mimic naturally occurring phenomena (e.g. mussel attachment). In this context, our team has joined these efforts to employ bio-inspired structures and approaches in biomaterials research, aiming at creating platforms and interface to understand and control cellular events. In particular, we successfully reproduced a bioactive nanoporosity on titanium, the gold standard in medicine, by simple chemical (i.e. oxidative nanopatterning) and electrochemical (i.e. anodization) methods, capable of positively affecting cell activity. Noteworthily, anodization permitted not only to create semiordered nanotubular surfaces which can be tuned in terms of diameter and spacing, but also a nanometric 3-dimensional hierarchical surface that mimics the silicified cell wall (frustule) of diatoms. This ultimately demonstrates that a simple anodization process can create complex periodic structures which, to date, have only been made by more complex techniques (e.g. two photon lithography, atomic layer deposition). These surfaces were exploited to close in on the mechanisms that control how human mesenchymal stem cells respond to nanotopographical surfaces, a fundamental aspect in expanding the present knowledge of cell-surface phenomena. In particular, our team focuses on the correlation between the geometrical arrangement of nanoscale features to specific cellular functions, and on the evaluation the effects of a vertical nanotopographical gradient by exploiting such bioinspired surface. Moreover, we are currently working on biologically inspired adhesive interfaces because of their potentially beneficial applications in medicine, technology and industry not only for their capacity to act as intermediate linkers to immobilize bioactive agents onto surfaces, but also for their ability to direct influence cell behavior. In particular, we focused on understanding the effects on cells of poly(dopamine), an adhesive polymer derived from mussels, as a multifunctional layer for supporting the activity of osteoblastic and human mesenchymal stem cells. In parallel, our team has also contributed to the development of bioinspired techniques and materials for tissue engineering applications.