This work illustrates how alternating current (AC)
electrokinetic effects (dielectrophoresis, electroosmosis) can
serve as contact-free templates, inside which colloidal microspheres
can assemble into a variety of shapes and sizes. We
show how three-dimensional colloidal structures of square,
circular, and diamond shape of many tens of micrometers in
size can be reproducibly formed with a single set of
quadrupolar microelectrodes