I. Levitan et al., A chamber to permit invasive manipulation of adherent cells in laminar flow with minimal disturbance of the flow field, ANN BIOMED, 28(10), 2000, pp. 1184-1193
An obstacle to real-time in vitro measurements of endothelial cell response
s to hemodynamic forces is the inaccessibility of the cells to instruments
of measurement and manipulation. We have designed a parallel plate laminar
flow chamber that permits access to adherent cells during exposure to flow.
The "minimally invasive flow device" (MIF device) has longitudinal slits (
1 mm wide) cut in the top plate of the chamber to allow insertion of a reco
rding, measurement, or stimulating instrument (e.g., micropipette) into the
flow field. Surface tension forces at the slit openings are sufficient to
counteract the hydrostatic pressure generated in the chamber and thus preve
nt overflow. The invasive probe is brought near to the cell surface, makes
direct contact with the cell membrane, or enters the cell. The slits provid
e access to a large number (and choice) of cells. The MIF device can mainta
in physiological levels of shear stress (<1-15 dyn/cm(2)) without overflow
in the absence and presence of fine instruments such as micropipettes used
in electrophysiology, membrane aspiration, and microinjection. Microbead tr
ajectory profiles demonstrated negligible deviations in laminar flow near t
he surface of target cells in the presence of microscale instruments. Patch
-clamp electrophysiological recordings of flow-induced changes in membrane
potential were demonstrated. The MIF device offers numerous possibilities t
o investigate real-time endothelial responses to well-defined flow conditio
ns in vitro including electrophysiology, cell surface mechanical probing, l
ocal controlled chemical release, biosensing, microinjection, and amperomet
ric techniques. (C) 2000 Biomedical Engineering Society. [S0090-6964(00)002
10-1].