Biomedical Engineering Reference
In-Depth Information
A
10E3
10E3
U1A
U1A
H
O
H
O
O
O
O
O
HO
HO
O
O
O
O
O
O
O
O
OH
OH
O
O
O
O
O
O
20
B
6E3
10 E3
40 nM
30 nM
0
20
−
FIGURE 12.22
Specific detection of mAbs binding to a recombinant
human autoantigen. (A) Scheme for specific recognition of
10E3 mAb with a nanotube device coated with a U1A anti-
gen-Tween conjugate. (B) QCM frequency shift vs. time
curve showing selective detection of 10E3 while showing
rejection of the antibody 6E3, which recognizes the highly
structurally related autoantigen TIAR. (C) Conductance
vs. time curve of a device shows specific response to
nnse
40
−
02468
t /10
3
(s)
1.02
1.01
1.00
0.99
0.98
0.97
1
µ
M I
g
G
1.04
1nM 10E3
1
nM 10E3 while rejecting polyclonal IgG at a much greater
concentration of 1
1.00
0.96
500
M (
Inset
). (From Chen, R. J.,
Bangsaruntip, S., Drouvalakis, K. A., Kam, N. W. S., Shim,
M., Li, Y., Kim, W., Utz, P. J., Dai, H. (2003). Noncovalent
Functionalization of Carbon Nanotubes for Highly
Specific Electronic Biosensors.
Proc. Natl. Acad. Sci. U.S.A.,
100, 4984-4989.)
700
t (s)
C
400
600
800
1000 1200
t (s)
(a)
(b)
(c)
FIGURE 12.23
FE-SEM (Leo 982, 1 kV) images of a CVD nanotube tip grown from a Si cantilever/tip assembly (a) before and
(b) after shortening. (c) TEM image (Philips EM420, 100 kV) of the pyramid-nanotube region of the tip shown in
panel b. The Si-pyramid is in the top-center of the image, and the two nanotubes comprising the tip are in the
bottom-center. Amorphous carbon on the nanotubes as deposited during FE-SEM imaging (a, b). The scale bars
in panels a-c are 500, 500, and 20 nm, respectively. (From Hafner, J. H., Cheung, C. Li., Lieber, C. M. (1999). Direct
Growth of Single-Walled Carbon Nanotube Scanning Probe Microscopy Tips.
J. Am. Chem. Soc
., 121(41),
9750-9751.). (From Hafner, J. H., Cheung, C. Li., Lieber, C. M. (1999). Direct Growth of Single-Walled Carbon
Nanotube Scanning Probe Microscopy Tips.
J. Am. Chem. Soc.
, 121(41), 9750-9751.)
resolution afforded by CNT probe tips also made it possible to directly read multiple
polymorphic sites in DNA fragments [191,192]. The CNT-based AFM tip has been
tested by identifying the spatial location of specific sequences in the M13mp18 plasmid.
This demonstrates the potential of the CNT tips for single-nucleotide polymorphism
detection [192].
