Biomedical Engineering Reference
In-Depth Information
50
50
1:3 RGDY:tyr-am
40
0
30
−
50
20
−
100
10
∆
R
−
150
0
10
−
−
200
−
20
−
250
∆
f
−
30
−
300
−
40
−
50
−
350
0
500
1000
1500
2000
2500
3000
3500
t
(s)
300
450
1:3 RGDY:tyr-am
Cells added
400
100
350
∆
R
∆
f
−
100
300
250
−
300
200
−
500
150
100
−
700
50
∆
f
−
900
−
0
∆
R
−
50
−
1100
0
5
10
15
20
t
(h)
FIGURE 1.24
Time course of film formation is presented in the upper panel measured via the
R
shifts of an electro-
chemical quartz crystal microbalance (EQCM) device during electropolymerization by a series of cyclic voltam-
metry (0-1.0 V) sweeps of the comonomer mixture, tetrapeptide Arg-Gly-Asp-Tyr (RGDY) and tyrosineamide in
a 1:3 ratio. In the lower panel, the time course of endothelial cell (EC) binding to the electropolymerized film is
presented for 20,000 cells added at the time indicated by arrowhead following a 2 h baseline signal with only
media and serum.
f
and
in a three-electrode electrochemical cell. This set-up can sensitively detect changes in mass
deposition down into the nanogram range via changes in the resonant frequency,
f
, and
motional resistance,
R
, of the oscillating quartz substrate. Originally developed for gas-
phase use, in the early 1980s solution-phase QCM was developed and has been applied to
a number of fundamental studies of biomolecular systems, polymeric systems and whole
cells. For a detailed discussion, we refer the reader to an extensive recent review from the
Center for Intelligent Biomaterials on the use of the QCM and EQCM in solution-based
biosensor and biomaterials characterization applications (65).