Selective DNA-Functionalization of Janus Particles and Their Self-assembly

Janus particles are quite unique building blocks due to their anisotropic nature. Unlike isotropic particles, it has been known that they can self-assemble into various structures such as micelles, vesicles, chains, bilayers, etc., due to their directional and geometrical interactions. One of the key factors governing the self-assembly behavior of Janus particles is the patch ratio, the ratio between the surface of the attractive patch and the total sphere surface. However, it is still challenging to control the patch ratio with existing methods. Here, we exhibit a novel fabrication method allowing us to accurately adjust the patch ratios of Janus particles in a wide range. Then, we show how to selectively functionalize one of the patches with DNA using a swelling-deswelling method for DNA-mediated self-assembly. Last, we demonstrate that the DNA-coated Janus particles can bind with each other only through the DNA-coated patches and self-assemble into various structures such as clusters, chains, rings, and bilayers.