3-D Fabrication Technology for Tissue Engineering

Tissue engineering typically involves the combination of cells and biomaterials to form tissues with the goal of replacing or restoring physiological functions lost in diseased organs. The biomaterial scaffolds are designed to provide mechanical support for the cells; however, in practice, the simple addition of cells to porous scaffolds often does not recapitulate sufficient tissue function. Scaffold design previously focused on the incorporation of macroscale features such as interconnected pores for nutrient transport and tissue remodeling. One strategy to further augment the function of tissue-engineered constructs is to mimic the in vivo tissue microarchitecture and cellular microenvirnment. Tissues in the body are divided into repeating functional units (e.g., nephron, islet) [1], whose 3-D architecture coordinates the processes of multiple types of specialized cells. Further, the local environment of these cells presents biochemical and physical stimuli that specifically modulate both cellular functions, e.g. biosynthesis and metabolism, and cellular fate processes such as differentiation, proliferation, apoptosis and migration. Thus, the fabrication of functional 3-D tissue constructs that incorporate both microscale features for appropriate cell functions and macroscale mechanical and transport properties demands control over chemistry and architecture over multiple length scales.