Synthetic Morphogens and Pro-morphogens for Aided Tissue Regeneration - Biologically Responsive Biomaterials for Tissue Engineering - page 55

inflammatory cells (i.e. monocytes/macrophages), other sequences have been
identified that are able to support osteoblast migration (i.e. FHRRIKA).

3.8 Current Limitations and Future Strategies to Improve

the Therapeutic Potential of Analogue Morphogens,
Growth Factors and Bioligands

The use of analogue morphogens, growth factors and bioligands in regenerative
medicine is certainly advocated as they allow a highly reproducible production of
biologically active molecules with no risk of transmittable disease. However,
although still in their infancy, limitations are already emerging that may prevent
their use in combination with biomaterials. It is therefore important to critically
assess these limitations in the view of the final clinical applications and to draw new
strategies aiming at improving the therapeutic potential of these peptides.

3.8.1 Current Limitations

One of the main possible limitations in the use of synthetic morphogens, growth
factors and bioligands in regenerative medicine is the binding affinity of the isolated
peptides that in other therapeutic applications has been shown to be relatively low
[ 62 ]. However, it has been demonstrated that the efficacy of these peptides can be
improved when conjugated with other molecules and carrier surfaces [ 63 ] . In the
case of bioligands, this is not a significant problem as they are designed to be grafted
on the surface of biomaterials to support cell adhesion and migration. Likewise, the
half-life of these relatively small peptides when administered in vivo is also short as
they are prone to degradation by hydrolysis and immune response. As discussed for
the natural growth factors and due to the potential low affinity for the cell receptors,
the bioavailability can also represent a significant limitation in the therapeutic use
of these molecules. From an industrial viewpoint, it is also worth mentioning that
the production (i.e. synthesis and purification) of these peptides can also be limited
by the feasibility of their scaling up. Addressing this issue appears to be the most
relevant step forward in the attempt to translate research findings into tools for clini-
cal treatments.

3.8.2 Future Strategies

Inevitably, future strategies to improve the therapeutic potential of analogue mor-
phogens, growth factors and bioligands have to mirror their current limitations and