Figure 3.

Janus particles as imaging probes for measuring rotational dynamics. (a) The 2-D projected imaging of a fluorescent 2-μm Janus particle gives the moon-like appearance, from crescent to full moon, as demonstrated in the fluorescence images at three different orientations. Images are color coded based on the fluorescence intensity. Reprinted with permission from ref. 124 Copyright 2006 American Chemical Society. (b) Single-particle tracking (left) of the in-plane rotational angle of a Janus particle that was half-coated with metal (right). Reprinted with permission from ref. 125 Copyright 2008 American Chemical Society. (c) Top: Single-particle tracking of the in-plane rotational angle (θ) of a Janus particle that was coated with two patches of proteins of different fluorescence. Bottom: A representative plot showing angle θ as a function of time during the cellular internalization of a Janus particle. Reprinted with permission from ref. 67 Copyright 2015 Royal Society of Chemistry.