Although the concept of sustained release has been
studied for decades, continued development of controlled-release
technologies have expanded the scope
of applications that can benefit from its implementation.
From what was once just a modality to achieve
zero-order release kinetics in drug delivery, controlled
release now is being used to enhance tissue engineering
and gene therapy applications, while providing
novel strategies for therapeutic angiogenesis.
This review has demonstrated the versatility and
utility of gelatin-based controlled-release systems in
such applications. By taking advantage of polyion
complexation, a diverse array of charged biomolecules
can be loaded into gelatin carriers while
retaining their inherent biological activity. In a manner
analogous to how the interaction of growth factors
with biological macromolecules in the extracellular
matrix regulates the function of such bioactive
molecules, implanted gelatin matrices are able to
protect loaded biomolecules from degradation and
release them for extended time periods. These
characteristics are complemented by the fact that by
altering the crosslinking density of the gelatin hydro-