Figure 13.

(a–h) Sequence optical images of electrostatic manipulation movement of columnar particles in micro channel filled with aqueous solution and detection of 130 nm diameter target particles via magnetically induced self-assembly of columnar particles. (a,b) Movement of a single 2.8 μm diameter magnetic particle in the microchannel; (c) The micrometer sized particle is magnetically captured by the immobilized target particles; (d,e) Another columnar particle is moved towards the location where the previous 2.8 μm diameter particle was captured; (f) Another columnar particle self-assembles onto the previous bead. (g,h) Columnar particles begin to move through the microchannel again in the absence of an external magnetic field due to the electric force still acting on the columnar particles. Adapted from [11].