This is a wonderfully whimsical way of demonstrating technology at work on the microscopic scale. From Physorg.com:
"We have made fluorescent lithographic particles, we have made complex three-dimensional shapes and, as shown by UCLA postdoctoral fellow Kun Zhao, we can assemble these particles, for example, in a lock-and-key relationship," said Mason, whose research is at the intersection of chemistry, physics, engineering and biology. "We can mass-produce complex parts having different controlled shapes at a scale much smaller than scientists have been able to produce previously. We have a high degree of control over the parts that we make and are on the verge of making functional devices in solution. We may later be able to configure the parts into more complex and useful assemblies."
Amazing stuff: and with such enormous potential.