Biomedical Engineering Reference
In-Depth Information
unique signal transduction platform for studying the behavior of cells during their attach-
ment to surfaces as well as their behavior once fully established on the surface. However,
the complexity of living cells makes stringent demands upon the investigator creating the
biosensor. As biological elements in a biosensor, living cells are far more subtle in their
sensitivity to complex environment effects than are individual biological macromolecules
as biosensor components. At a minimum, cells typically must be maintained at constant
temperature within defined growth media inside a sterile environment, to provide accu-
rate output responses and to prevent their contamination with microrganisms. On the
other hand, the reward is that cell-containing biosensors can be far more valuable for spe-
cific applications because they exploit the full range of intelligent properties possessed by
living cells.
1.2.3.2.2 Cell Quartz Crystal Microbalance Biosensor Detection of Cytoskeleton Binding
Drugs
The above studies examining novel details of the cell attachment process during formation
of the QCM biosensor were preparatory to our main goal of creating sensitive cell QCM
biosensors for drug discovery applications. To implement this, we used as the biological
element ECs attached to the QCM device surface at the steady-state condition correspon-
ding to ~20 h postcell addition, where constant frequency and motional resistance values
were exhibited. We show a schematic diagram of this biosensor set-up in Figure 1.33A (96).
An integral feature of this biosensor is the requirement for endothelial cells to maintain
(A)
Cover plate
CO
2
incubator (37
C)
°
Oscillator
QCA 917
frequency
admittance
O-ring
Au surface
O
O
QCM crystal
O
O
Computer
H
2
O
(B)
Signal transducing
biological structures
Cytoskeleton
(microtubules)
Nuclei
ECs
Focal adhesion
complexes
ECM
Au
X
X
XXXXXXXXXXXXX
X
X
XXXXXXXXXXXXX
X
X
XXXXXXXXXXXXX
Quartz crystal
FIGURE 1.33
Schematic diagrams of (A) the entire cell QCM biosensor measurement system and (B) cell QCM biosensor sur-
face with labeled signal transduction elements. Reprinted from Marx, K.A., Zhou, T., Montrone, A., Schulze, H.,
Braunhut, S. J. (2001). A Quartz Crystal Microbalance Cell Biosensor: Detection of Microtubule Alterations in
Living Cells at nM Nocodazole Concentrations.
Biosen. Bioelectron.
16:773-782. With permission from Elsevier
Publishing.
