ABSTRACT
Xin Zhao, Šeila Selimović, Gulden Camci-Unal, Mehmet R. Dokmeci, Lara Yildirimer, Nasim Annabi, and Ali Khademhosseini
Tissue engineering is a rapidly growing research area aiming to repair damaged organs or tissues by utilizing an interdisciplinary approach at the interface between medicine, physical sciences, and engineering (Langer and Vacanti, 1993). The functionality of engineered tissues highly depends on the vascularization of the resulting constructs because
CONTENTS
8.1 Introduction ........................................................................................................................ 143 8.2 Vascular Structures ........................................................................................................... 145
8.2.1 Structure of Blood Vessels .................................................................................... 145 8.2.1.1 Arteries and Arterioles ........................................................................... 145 8.2.1.2 Veins and Venules ................................................................................... 146 8.2.1.3 Capillaries ................................................................................................ 146
8.2.2 Overview of Blood Vessel Formation ................................................................. 146 8.2.2.1 Origin of Blood Vessels .......................................................................... 146 8.2.2.2 Angiogenic Process ................................................................................. 147
8.3 Microfabrication Technologies ......................................................................................... 147 8.3.1 Micromolding ......................................................................................................... 148 8.3.2 Photolithography ................................................................................................... 149 8.3.3 Rapid Prototyping ................................................................................................. 151
8.4 Generating 3D Vascularized Tissue Constructs Using Microuidic Systems .......... 152 8.5 Application of Biomaterials, Growth Factors, and Cell Coculture for Vascular
Structure Development ..................................................................................................... 156 8.5.1 Biomaterials for Guiding Vessel Growth ........................................................... 156
8.5.1.1 Natural Materials .................................................................................... 156 8.5.1.2 Synthetic Materials ................................................................................. 157
8.5.2 Vascularization Enhancement by Growth Factors ........................................... 157 8.5.3 Vascularization Enhancement by Cell Coculture ............................................. 158
8.6 Conclusions and Future Directions ................................................................................ 158 References ..................................................................................................................................... 159
most of the vital organs are highly vascularized in the native environment. For example, heart, kidney, liver, and lung possess complex microarchitectural units surrounded by a dense network of blood vessels. The vasculature in the body provides the tissues with oxygen and nutrients, as well as facilitates the removal of metabolic waste and unwanted metabolites (Du et al., 2008). The engineered tissue units, if not prevascularized, are likely to experience substantial problems due to diffusion-based limitations. Although avascular tissues, such as bladder, heart valve, cartilage, or skin, have previously been successfully engineered, currently, there is a tremendous need for developing strategies to generate vascularized tissues and organs (Ashiku et al., 1997, Atala et al., 2006, Auger et al., 2009, Cebotari et al., 2010).
