Biomedical Engineering Reference
In-Depth Information
Nano-
cavity
D
L
Nanopore
150
μ
m
Etching
b
200 ms
1000 ms
c
Cyclodextrin
and
Chiral enantiomers
Time
440 pA
15 ms
S-ibuprofin
R-ibuprofin
H
HO
O
Fig. 3.6 Glass nanopore-terminated probe and single molecule manipulation [
28
]. (a) The glass
nanopore is fabricated by sealing the micropipette terminal to enclose a nanocavity, followed by
external etching the glass terminal with electrical monitoring to perforate the nanocavity with
controllable pore size. (b) Current blocks showing translocation of 1 kbp dsDNA through a 2-nm
nanopore (
left
) and a 7-nm pore (
right
) in 1 M NaCl (+100 mV). When the pore size is comparable
to dsDNA, the DNA translocation speed is slowed down and translocation steps can be revealed
from the block type (
left
), which is different from that for DNA translocation in a wider pore
(
right
). (c) Single molecule discrimination of chiral enantiomers by the cyclodextrin (1.5 nm)
trapped in the 1 nm nanopore. The interaction of chiral compounds with cyclodextrin can be
separated from their block durations and current amplitudes. The current trace showed the binding
of individual enantiomers of ibuprofen to the trapped
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