Biomedical Engineering Reference
In-Depth Information
of suficient osseointegration between synthetic materials and bone
tissue.
12.2 Biocompatibility
The biocompatibility of biomaterials is very closely related to cell
behavior in contact with them, and particularly to cell adhesion
to their surface [12]. Surface characteristics of materials, such as
their topography, chemistry, or surface energy, play an essential
part in osteoblast adhesion to biomaterials. The term “adhesion”
in the biomaterial domain covers different phenomena [8, 12]: the
attachment phase which occurs rapidly and involves short-term
events like physicochemical linkages between cells and materials
involving ionic forces, van der Walls forces, etc., and the adhesion
phase occurring in the longer term and involving various biological
molecules: extracellular matrix proteins, cell membrane proteins,
and cytoskeleton proteins which interact together to induce signal
transduction, promoting the action of transcription factors, and
consequently regulating gene expression.
Studies have demonstrated that nanostructured materials with
cell favorable surface properties may promote greater amounts of
speciic protein interactions to stimulate more eficiently new bone
growth compared to conventional materials [29, 136, 140]. This
may be one of the underlying mechanisms why nanomaterials are
superior to conventional materials for tissue growth. Therefore, by
controlling surface properties, various nanophase ceramic, polymer,
metal, and composite scaffolds have been designed for bone/
cartilage tissue engineering applications.
The biocompatibility of an artiicial material in the body is
complicated. The artiicial implants, once implanted
in vivo
, induce
a cascade of reactions in the biological micro-environment through
interaction of the biomaterial with body luid, proteins, and various
cells [43, 45, 119, 145]. The sequence of local events often leads to
the classic foreign body response and the formation of a ibrous
tissue capsule around an implant. It is clear that a major factor
inluencing this unfavorable reaction of the body is the biomaterial
surface. The speciic interactions determine the path and speed of
the healing process and the long-term integration of the biomaterial-
body interface. Both the chemical composition of the surface
