Biomedical Engineering Reference
In-Depth Information
Stuart et al. (2006)
recently published the first
in vivo
application of SERS. They used SERS
to obtain quantitative
in vivo
glucose measurements from an animal model. They
functionalized the silver film covered nanosphere surfaces with a two-component self-
assembled monolayer. These authors subcutaneously implanted the nanospheres into a
Sprague-Dewey rat, and were able to measure the glucose concentrations of the interstitial
fluid by spectroscopically addressing the sensor through an optical window.
The authors were able to develop a technique that addresses the critical problems that limit
the use of SERS to glucose measurements, particularly,
in vivo
. They developed (a) strong
and stable enhancing SERS-active surfaces, and (b) chemical functionalization of those
surfaces with self-assembled monolayers (SAMs). (
Yonzon et al., 2004; Lyandres et al.,
2005; Stuart et al., 2005
).
Stuart et al. (2006)
further reported that these SAMs improve
the glucose signal (
Shafer-Peltier et al., 2003; Yonzon et al., 2005; Dieringer et al., 2006
).
Stuart et al. (2006)
used intermittent intravenous infusion for three hours to vary the glucose
in the rat. These authors delivered the glucose infusion via the femoral cannula. Sterile
phosphate-buffered saline at a glucose concentration of 1 g/mL was delivered over a period
of 5-10 min. A droplet of blood was drawn from the rat and measured with the One Touch II
glucometer and the corresponding SERS measurements were made by the SERS sensor.
Figure 12.7a
shows the binding of the glucose to the One Touch II glucometer using an
in vivo
analysis.
Stuart et al. (2006)
pointed out that the standard glucometer effectively
tracked the change in the glucose concentration. A single-fractal analysis is adequate to
describe the binding kinetics. The values of the binding rate coefficient,
k
, and the fractal
dimension,
D
f
, for a single-fractal analysis are given in
Table 12.4
.
250
100
80
200
150
60
100
40
50
20
0
0
0
20
40
60
Time (min)
80
100
120
140
0
20
40
60
80
100
120
140
A
B
Figure 12.7
(a) Binding indicating the time course of glucose measurement by One Touch II blood glucose
meter (
Stuart et al., 2006
), (b) Binding indicating the time course of glucose measurement by SERS
sensor (
Stuart et al., 2006
).
Time (min)
