Biomolecule Use in Tissue Engineering

Abstract

Tissue engineering is an interdisciplinary field in biomedical engineering that aims to regenerate new biological material to replace diseased or damaged tissues or organs. Tissue engineering is based on principles of cellular and molecular developmental biology and morphogenesis guided by bioengineering and biomechanics. The three key ingredients for both morphogenesis and tissue engineering are inductive signals (regulatory biomolecules, morphogens), responding cells and extracellular matrix (scaffolds) [108]. Morphogens regulate the proliferation and differentiation of cells, whereas scaffolds serve as a carrier and delivery system for the morphogens and simultaneously produce and influence the microenvironment [113]. Regulatory biomolecules, such as differentiation or growth factors and cytokines, are released by many different sorts of cells in a diverse manner (endocrine, autocrine, paracrine, juxtacrine or intracrine), targeted at a particular cell or cells to carry out a specific reaction (Tables 11.1, 11.2) [75]. The term cytokine is generally reserved to describe factors associated with cells involved in the immune system, but in many instances the term growth factor is used as a synonym for cytokines [101]. When a growth factor binds to a target cell receptor an intracellular signal transduction system is activated that finally reaches the nucleus and produces a biological response [79]. These ligand-receptor interactions are very specific and vary from the simple binding of one ligand to one particular cellular receptor to complex interactions with one or more ligands binding to one or more receptors. Additionally, the ligand-receptor interactions are even more complicated as different variants of the same growth factor may bind to a single receptor, or different growth factor receptors may be activated by a single ligand [53].