Scaffold Design for Bone Tissue Engineering: From Micrometric to Nanometric Level - Biologically Responsive Biomaterials for Tissue Engineering - page 3

Fig. 1.1 Scheme of basic aspects involved in scaffold design for bone at micrometric and
nanometric level
To act as an ECM substitute, a scaffold should impart a 3-D geometry, show
appropriate mechanical properties, enable cell attachment, and facilitate the advance
of biological events involving cell activities during the formation of a functional
tissue. At the microscopic level, a highly porous structure is absolutely essential to
support the diffusion of nutrients and waste products through the scaffold. By this
time, an optimal pore size is largely recognized in several matrices for cellular
response in tissue regeneration (of bone, liver, nerve, cartilage) and for neo-vascu-
larization [ 44, 55 ]. Indeed, the optimal pore size tailored on the specific cell type has
to be large enough to allow for cell migration and ECM formation yet not be so
small that pore occlusion occurs. This balance often presents a trade-off between a
denser scaffold which provides better supporting function and a more porous scaf-
fold which enables better interaction with the cell component.
Here, the key issue will be the identification and analysis of the materials and
processing techniques which are able to develop micro- and nano-structured
platforms. These are necessary to assure an optimal balance in terms of cell
recognition, mass transport properties, and mechanical response in order to repro-
duce the morphological and functional features of new tissue at the microscopic
and nanoscopic level.