Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Wiley Interdiscip Rev Nanomed Nanobiotechnol. 2012 May-Jun;4(3):235-46. doi: 10.1002/wnan.171. Epub 2011 Dec 5.
Hydrogels represent a class of materials suitable for numerous biomedical applications such as tissue engineering and drug delivery. Hydrogels are by definition capable of absorbing large amount of fluid, making them adequate for cell seeding and encapsulation as well as for implantation because of their biocompatibility and excellent diffusion properties. They also possess other desirable properties for fundamental research as they have the ability to mimic the basic three-dimensional (3D) biological, chemical, and mechanical properties of native tissues. Furthermore, their biological interactions with cells can be modified through the numerous side groups of the polymeric chains. Thus, the biological, chemical, and mechanical properties, as well as the degradation kinetics of hydrogels can be tailored depending on the application. In addition, their fabrication process can be combined with microtechnologies to enable precise control of cell-scale features such as surface topography and the presence of adhesion motifs on the hydrogel material. This ability to control the microscale structure of hydrogels has been used to engineer tissue models and to study cell behavior mechanisms in vitro. New approaches such as bottom-up and directed assembly of microscale hydrogels (microgels) are currently emerging as powerful methods to enable the fabrication of 3D constructs replicating the microenvironment found in vivo.
水凝胶是一类适用于组织工程和药物输送等众多生物医学应用的材料。根据定义，水凝胶能够吸收大量的液体，这使它们适合细胞播种和封装以及植入，因为它们具有生物相容性和优异的扩散性能。由于它们具有模拟天然组织基本三维（3D）生物、化学和机械特性的能力，它们还具有其他基础研究所需的理想特性。此外，可以通过聚合物链的众多侧基来修饰它们与细胞的生物相互作用。因此，水凝胶的生物、化学和机械特性以及降解动力学可以根据应用进行定制。此外，它们的制造工艺可以与微技术结合，以实现对细胞尺度特征的精确控制，例如表面形貌和水凝胶材料上的粘附基序的存在。控制水凝胶微结构的这种能力已被用于工程组织模型和体外研究细胞行为机制。目前，诸如自下而上和微尺度水凝胶（微凝胶）的定向组装等新方法正在涌现，成为实现制造复制体内微环境的 3D 结构的有力方法。
