The combination of laser tweezers and dielectric field cages is demonstrate
d. This opens up new possibilities of, e.g., ultrasensitive receptor-ligand
force measurements in the pN range with suspended cells, the three-dimensi
onal calibration of laser tweezers force and a 'microtuning lathe' for proc
essing microparticles with an additional UV-microbeam, (C)2000 Elsevier Sci
ence B.V. All rights reserved.