  A key issue for the fabrication of scaffolds for tissue engineering is the
development of processing techniques flexible enough to produce materials with
a wide spectrum of solubility (bioresorption rates) and mechanical properties
matching those of calcified tissues. These techniques must also have the
capability of generating adequate porosity to further serve as a framework for
cell penetration, new bone formation, and subsequent remodeling. In this study,
we show how hybrid organic/inorganic scaffolds with controlled microstructures
can be built using robotic assisted deposition at room temperature. Polylactide
or polycaprolactone scaffolds with pore sizes ranging between 200-500 {\mu}m
and hydroxyapatite contents up to 70 wt % were fabricated. Compressive tests
revealed an anisotropic behavior of the scaffolds, strongly dependent on their
chemical composition. The inclusion of an inorganic component increased their
stiffness but they were not brittle and could be easily machined even for
ceramic contents up to 70 wt%. The mechanical properties of hybrid scaffolds
did not degrade significantly after 20 days in simulated body fluid. However,
the stiffness of pure polylactide scaffolds increased drastically due to
polymer densification. Scaffolds containing bioactive glasses were also
printed. After 20 days in simulated body fluid they developed an apatite layer
on their surface.
