Department of Physics, New York University, 4 Washington Place, New York, New York 10003, USA.
Nature. 2010 Mar 25;464(7288):575-8. doi: 10.1038/nature08906.
New functional materials can in principle be created using colloids that self-assemble into a desired structure by means of a programmable recognition and binding scheme. This idea has been explored by attaching 'programmed' DNA strands to nanometre- and micrometre- sized particles and then using DNA hybridization to direct the placement of the particles in the final assembly. Here we demonstrate an alternative recognition mechanism for directing the assembly of composite structures, based on particles with complementary shapes. Our system, which uses Fischer's lock-and-key principle, employs colloidal spheres as keys and monodisperse colloidal particles with a spherical cavity as locks that bind spontaneously and reversibly via the depletion interaction. The lock-and-key binding is specific because it is controlled by how closely the size of a spherical colloidal key particle matches the radius of the spherical cavity of the lock particle. The strength of the binding can be further tuned by adjusting the solution composition or temperature. The composite assemblies have the unique feature of having flexible bonds, allowing us to produce flexible dimeric, trimeric and tetrameric colloidal molecules as well as more complex colloidal polymers. We expect that this lock-and-key recognition mechanism will find wider use as a means of programming and directing colloidal self-assembly.
新的功能材料原则上可以通过使用胶体自组装成所需结构的可编程识别和结合方案来创建。通过将“编程”的 DNA 链附着到纳米级和微米级颗粒上，然后使用 DNA 杂交来指导颗粒在最终组装中的放置，已经探索了这种想法。在这里，我们展示了一种基于互补形状颗粒的用于指导复合结构组装的替代识别机制。我们的系统基于 Fischer 的锁钥原理，使用胶体球作为钥匙，使用具有球形空腔的单分散胶体颗粒作为锁，通过消耗相互作用自发且可逆地结合。锁钥结合是特异性的，因为它由球形胶体钥匙颗粒的尺寸与锁颗粒的球形空腔的半径匹配的程度来控制。通过调整溶液组成或温度，可以进一步调整结合的强度。复合组装具有柔性键的独特特征，使我们能够生产灵活的二聚体、三聚体和四聚体胶体分子以及更复杂的胶体聚合物。我们预计这种锁钥识别机制将作为一种编程和指导胶体自组装的手段得到更广泛的应用。
