Bioinspired Materials Science and Engineering

12Preparation of Gradient Polymeric Structures and Their Biological Applications

Tao Du¹, Feng Zhou¹, and Shutao Wang^2,*

¹ State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, China

² CAS Key Laboratory of Bio‐inspired Materials and Interfacial Science, CAS Center for Excellence in Nanoscience, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China

12.1 Introduction

After long time of evolution and natural selection, gradients exist in many biological systems, such as bones and plant stems. For example, spatial variations in cell types present at the anterior cruciate ligament (ACL)‐to‐bone junction [1]. In the ligament and bone regions, the content of collagen is highest. Along the fibrocartilage interface, the relative collagen content decreases from ligament to bone (Figure 12.1a) [1]. In developmental biology, the morphogen forms a gradient of concentration to determine the fate of responding cells [2]. In plant stems, the fiber cap region exists a stiffness gradient (Figure 12.1b) [3, 4]. These gradients in living systems are often at levels that scientists can only envy. Thus, artificial gradient structures have aroused great interest because of their very wide range of applications not only in tissue engineering [5], but also in implantable materials [6], chemotactic gradients [7], cell migration [8], cell gradients [9, 10], and so forth.

Figure 12.1 Gradient structures ...