Synthesis of multifunctional micrometer-sized particles with magnetic, amphiphilic, and anisotropic properties.

Well-defi ned, functional colloids provide critical model systems for a variety of fundamental phenomena in materials and soft matter, and enable a broad range of technological applications from optics [ 1 ] to biotechnology. [ 2 ] The ability to fabricate large quantities of colloids with high uniformity and specifi ed shape and function has thus been greatly desired. For example, magnetic colloids can be externally manipulated and controlled, and have been used in applications ranging from photonic crystals, [ 3 ] cell sorting, [ 2 ] biosensors, [ 4 ] drug delivery, [ 5 ] biomedical applications, [ 6 ] and single-molecule biophysics. [ 7 ] Magnetic colloids that can be remotely controlled by applied fi elds have also been exploited in m-ink, [ 8 ] microrheological probes, [ 9–11 ] and a variety of self-organizing systems. [ 12 , 13 ] In a similar fashion, ferrofl uids and magneto-rheological fl uids are frequently used to make useful materials because of their tuneable dynamic response. [ 14 , 15 ]