Optical forces for noninvasive cellular analysis.
A novel, noninvasive measurement technique for quantitative cellular analysis is presented that utilizes the forces generated by an optical beam to evaluate the physical properties of live cells in suspension. In this analysis, a focused, near-infrared laser line with a high cross-sectional intensity gradient is rapidly scanned across a field of cells, and the interaction of those cells with the beam is monitored. The response of each cell to the laser depends on its size, structure, morphology, composition, and surface membrane properties; therefore, with this technique, cell populations of different type, treatment, or biological state can be compared. To demonstrate the utility of this cell analysis platform, we evaluated the early stages of apoptosis induced in the U937 cancer cell line by the drug camptothecin and compared the results with established reference assays. Measurements on our platform show detection of cellular changes earlier than either of the fluorescence-based Annexin V or caspase assays. Because no labeling or additional cell processing is required and because accurate assays can be performed with a small number of cells, this measurement technique may find suitable applications in cell research, medical diagnostics, and drug discovery.
Wang
Mark M
MM
Genoptix, Inc., 3398 Carmel Mountain Road, San Diego, California 92121, USA. mwang@genoptix.com
Schnabel
Catherine A
CA
Chachisvilis
Mirianas
M
Yang
Rong
R
Paliotti
Michael J
MJ
Simons
Laura A
LA
McMullin
Laura
L
Hagen
Norbert
N
Lykstad
Kristie
K
Tu
Eugene
E
Pestana
Luis M
LM
Sur
Sudipto
S
Zhang
Haichuan
H
Butler
William F
WF
Kariv
Ilona
I
Marchand
Philippe J
PJ
D017209:Apoptosis; D006801:Humans; D007834:Lasers; D009369:Neoplasms / Q000473:pathology* / Q000503:physiopathology; D055095:Optics and Photonics / Q000295:instrumentation; D013997:Time Factors; D014407:Tumor Cells, Cultured