Zhang Shuguang
Center for Biomedical Engineering NE47-379, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, USA.
Nat Biotechnol. 2003 Oct;21(10):1171-8. doi: 10.1038/nbt874.
Two complementary strategies can be used in the fabrication of molecular biomaterials. In the 'top-down' approach, biomaterials are generated by stripping down a complex entity into its component parts (for example, paring a virus particle down to its capsid to form a viral cage). This contrasts with the 'bottom-up' approach, in which materials are assembled molecule by molecule (and in some cases even atom by atom) to produce novel supramolecular architectures. The latter approach is likely to become an integral part of nanomaterials manufacture and requires a deep understanding of individual molecular building blocks and their structures, assembly properties and dynamic behaviors. Two key elements in molecular fabrication are chemical complementarity and structural compatibility, both of which confer the weak and noncovalent interactions that bind building blocks together during self-assembly. Using natural processes as a guide, substantial advances have been achieved at the interface of nanomaterials and biology, including the fabrication of nanofiber materials for three-dimensional cell culture and tissue engineering, the assembly of peptide or protein nanotubes and helical ribbons, the creation of living microlenses, the synthesis of metal nanowires on DNA templates, the fabrication of peptide, protein and lipid scaffolds, the assembly of electronic materials by bacterial phage selection, and the use of radiofrequency to regulate molecular behaviors.
在分子生物材料的制备中可采用两种互补策略。在“自上而下”的方法中，生物材料是通过将一个复杂的实体拆解成其组成部分而生成的（例如，将病毒颗粒拆解到其衣壳以形成病毒笼）。这与“自下而上”的方法形成对比，在“自下而上”的方法中，材料是逐个分子（在某些情况下甚至是逐个原子）组装以产生新型超分子结构。后一种方法可能会成为纳米材料制造的一个组成部分，并且需要对单个分子构建单元及其结构、组装特性和动态行为有深入的了解。分子制造中的两个关键要素是化学互补性和结构兼容性，这两者都赋予了在自组装过程中将构建单元结合在一起的弱相互作用和非共价相互作用。以自然过程为指导，在纳米材料与生物学的界面上已经取得了重大进展，包括用于三维细胞培养和组织工程的纳米纤维材料的制备、肽或蛋白质纳米管和螺旋带的组装、活微透镜的创建、DNA模板上金属纳米线的合成、肽、蛋白质和脂质支架的制备、通过噬菌体筛选组装电子材料以及使用射频来调节分子行为。
