Janus particles

Janus particles are special types of nanoparticles or microparticles whose surfaces have two or more distinct physical properties.^[1][2] This unique surface of Janus particles allows two different types of chemistry to occur on the same particle. The simplest case of a Janus particle is achieved by dividing the particle into two distinct parts, each of them either made of a different material, or bearing different functional groups.^[3] For example, a Janus particle may have one half of its surface composed of hydrophilic groups and the other half hydrophobic groups,^[4] the particles might have two surfaces of different color,^[5] fluorescence, or magnetic properties.^[6] This gives these particles unique properties related to their asymmetric structure and/or functionalization.^[7]