Biomedical Engineering Reference
In-Depth Information
Fig. 7
Lipid, peptide and protein scaffold nanowires.
a
Lipid tubule-coated wire. Nanopar-
ticles are coated on the left-handed helical lipid tubules. The nanoparticles are aligned
insidethetubulealongtheregularhelicalpattern[66].(ImagecourtesyofJ.Schnur.)
b
Silver ions fill the nanotubes formed from a dipeptide, Phe-Phe, the shortest pep-
tide possible. The silver alone formed a wire after removal of the Phe-Phe peptide
scaffold [67]. (Image courtesy of M. Reches and E. Gazit.)
c
Discovery and selection of
electronic materials using a bacteriophage display system. A combinatorial phage library
was used to selectively bind to electronic materials. Selected recombinant phage peptide
has a high affinity for GaAs. Fluorescently labeled phage has displaced the peptide speci-
ficity for GaAs and is capable of binding to the patterned GaAs nested in the square
pattern on a wafer. The red line (1
µ
m in diameter) corresponds to GaAs and the black
spaces (4
m in diameter) are SiO
2
. This peptide-specific binding could also potentially
be used to deliver nanocrystals to specific locations [69]. (Image courtesy of A. Belcher.)
µ
est in developing various methods for attaching conducting metal nanocrys-
tals to a peptide for such a purpose.
3.4.1
From Nanotube to Nanowire
Matsui and colleagues [80] have reported success in functionalizing pep-
tide nanotubes into nanowires. They not only coated the peptide nanotube
with copper and nickel but also showed that their nanotubes can be coated
with avidin, making them able to bind specifically to gold surfaces that have
previously been treated with biotinylated self-assembled nanolayers. Lvov
et al. [81] have fabricated nano- and microwires by coating the lipid tubules
with silica and gold nanocrystals. They found that these nanocrystals are
linked to the tubules according to the tubules' helical periodicity. These wires
have been used for coating in a number of industrial applications. Reches
and Gazit have demonstrated that a Phe-Phe dipeptide—the shortest pep-
tide length possible, consisting of only two amino acids with a single amide
bond—can form stable nanotubes. They then diffused silver ions into the
defined tubes and were able to remove the peptide either enzymatically,
chemically or through heat burning to reveal the silver wire [82].
In other recent work, amyloid protein nanofibers have been used as scaf-
fold to align gold nanocrystals. Lindquist and colleagues [83] have reported
how a bioengineered version of the prion-determining (NM) domain of the
yeast prion protein Sup35 can provide a scaffold for fabricating nanowires,
