Analysis of the reaction of bone structure to mechanical stimulation is a key issue in understanding the origins of osteoporosis and mechanical adaptation of living bone to external forces. This is thought to be regulated on a cellular level. We have investigated quantitative mechanical stimulation of single bone cells and their immediate intracellular calcium responses using a combination of an atomic force microscope (AFM) and a fluorescence microscope, developed in our laboratory. The force stimulation system can apply quantified forces in the pico- and nano-newton regime on exactly defined positions of a cell. We present here the first measurements using this system on the mechanically induced free calcium response of primary osteoblasts. The threshold forces for stimulation and the temporal behavior of the free calcium response are analyzed and the signal transmission to adjacent cells is investigated. An immediate increase of the intracellular calcium concentration is observed after dynamic stimulation with forces between 110nN and 550nN. Forces exceeding 700nN destroy the cell and the free calcium concentration of the neighboring cells react as a consequence.

Date Published: 10 May 2001
PDF: 9 pages
Proc. SPIE 4260, Optical Diagnostics of Living Cells IV, (10 May 2001); doi: 10.1117/12.426764

Published in SPIE Proceedings Vol. 4260:
Optical Diagnostics of Living Cells IV
Daniel L. Farkas; Robert C. Leif; Robert C. Leif, Editor(s)