Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA, 02155, USA.
Silklab, Tufts University, 200 Boston Avenue, Medford, MA, 02155, USA.
Adv Mater. 2017 Oct;29(38). doi: 10.1002/adma.201702769. Epub 2017 Aug 18.
Structural proteins from naturally occurring materials are an inspiring template for material design and synthesis at multiple scales. The ability to control the assembly and conformation of such materials offers the opportunity to define fabrication approaches that recapitulate the dimensional hierarchy and structure-function relationships found in nature. A simple and versatile directed assembly method of silk fibroin, which allows the design of structures across multiple dimensional scales by generating and tuning structural color in large-scale, macro defect-free colloidally assembled 3D nanostructures in the form of silk inverse opals (SIOs) is reported. This approach effectively combines bottom-up and top-down techniques to obtain control on the nanoscale (through silk conformational changes), microscale (through patterning), and macroscale (through colloidal assembly), ultimately resulting in a controllable photonic lattice with predefined spectral behavior, with a resulting palette spanning almost the entire visible range. As a demonstration of the approach, examples of "multispectral" SIOs, paired with theoretical calculations and analysis of their response as a function of changes of lattice constants and refractive index contrast are illustrated.
天然存在的材料中的结构蛋白是在多个尺度上进行材料设计和合成的灵感模板。控制此类材料的组装和构象的能力为定义制造方法提供了机会，这些方法再现了自然界中发现的维度层次结构和结构-功能关系。本文报道了一种简单而通用的丝素蛋白定向组装方法，该方法通过在大规模、宏观无缺陷的胶体组装 3D 纳米结构中生成和调整结构色，从而在多个维度尺度上设计结构，这种结构色以丝质反转蛋白石（SIO）的形式存在。该方法有效地结合了自下而上和自上而下的技术，从而实现了对纳米尺度（通过丝蛋白构象变化）、微尺度（通过图案化）和宏观尺度（通过胶体组装）的控制，最终得到了具有预定光谱行为的可控光子晶格，其结果色板几乎涵盖了整个可见光范围。作为该方法的一个演示，本文举例说明了“多光谱”SIO，并结合理论计算和对其响应的分析，说明了其作为晶格常数和折射率对比度变化函数的响应。
