In their quest to study ever smaller and smaller particles, scientists have hit on particles too small even to be captured in a wavelength of light. What can you use to trap these particles? Meet the electrostatic trap.
An older post on Io9 discussed optical traps as a way to deal with particles too small or delicate to be held with conventional fixing materials. Optical manipulators trapped such particles in beams of light. If the particle were to wander one way, the beam of light would be diverted outwards, and kick the particle back to the middle of the beam. The post made much of how current science was entirely too involved with small things.