Hierarchical scaffolds obtained by nonconventional layer-by-layer electrostatic self-assembly

The introduction of nano/micro structures in scaffolds is of great interest as a way to achieve a better control over cells environment. Layer-by-Layer (LbL) is a very versatile technique for surface modification by the self-assembly of polyelectrolytes (PE). However, until now, few works have reported the introduction of coatings or reservoirs of bioactive molecules on porous structures using PE. This work introduces a non-conventional approach of LbL to create nano/micro fibrillar-like structures of chitosan and alginate inside and linked onto polycaprolactone scaffolds previously produced by rapid prototyping, resulting in hierarchical scaffolds. Several assembling parameters were studied, verifying that the washing step and the concentrations were variables
influencing more cell behaviour. The behaviour of SaOs-2 cell line was assessed on these hierarchical scaffolds by quantifying dsDNA and ALP activity, and observing cell distribution after 1 and 7 days in culture.
Cell seeding efficiency was improved with the introduction of hierarchical structures and, after 7 days, the cells had colonized the whole scaffold. ALP/dsDNA was higher than on 2D culture plates and, in general, was not influenced by the introduction of the structures. In conclusion, the methodology proposed permits to modify the surface or add a new hierarchical structural level in scaffolds for TE that could be used to control cell adhesion, proliferation and differentiation.