Grasping and moving objects without contact .
For example, it is general practice in cell manipulation to suck up
cells with a glass micropipette and handle them mechanically, but this contact damages the sample
and/or changes the physical and chemical conditions. One method of non-contact handling is laser
trapping. With this method, the pressure of the light to the object (radiation pressure)
manipulates the object without contact or damage. According to electromagnetic theory, the force
generated by a 1 mW-laser beam is 7 pN.